Suspension

[redline]

I adjusted my suspension by trying to learn here from the forum and other books but still didn't get it right. I was close but was off by 7 clicks in the front and 5 in the back and what a difference that made getting this right. not diving anymore in the front and we'll see when i go up the mountain how it perfomrs. was riding with a new buddy i met here and wasn't trying to race him but kept scraping my crash bars. He did tell me that the line I was using is more aggressive with more lean angle than what he was doing at the same speed which was a good reminder again to practice, practice, practice.
But I have never scraped the little silver plate before....
The suspension adjustment might help a little and riding a later apex ...... We'll see how I do next time but I was glad that the guy told me to see this mechanic to get this looked at and for 40.00 (motopia a triumph dealer albuquerque) adjusted that for me.
I ride alone most of the time and it's great when you have someone follow you and give you input of what you might be doing wrong or could be doing better.....

 

[connie_rider]

What crash bars are on the bike?

 

[redline]

t-rex

 

[Fred H.]

Article published in Concourier in 2012

 

[2andblue]

@redline please don’t be next to go down from unloading your tires - scraping crash bars is a disaster waiting to happen.

Previous the shop’s adjustment Have you measured your sag yet or making adjustments by feel? Measuring is only proper way.

Wayne, Carol & Blue

 

[redline]

@redline please don’t be next to go down from unloading your tires - scraping crash bars is a disaster waiting to happen.

Previous the shop’s adjustment Have you measured your sag yet or making adjustments by feel? Measuring is only proper way.

Wayne, Carol & Blue

I made some adjustments because is was obvious the suspension was way off but not being an expert and thinking I was following the right advice I first of all did not do that correctly and probably needed better knowledge and understanding to this right. the weird thing is i thought i had the clicks right, you wouldn't think it would be difficult to do when someone tells you go all the way to the end then back off that many clicks. is it possible that it changed by itself over time? I wouldn't think so. in any case I now have a baseline and good setup and hope that scraping the crash bars won't happen again. I'll adjust how I ride to take away more lean angle which I should have practiced before more but again not really ran into this issue but one time before. Yes, not interested in unloading those tires, saw what that looks like last year. not pretty. I mainly wanted to share this as a reminder to check those things on our bikes as well as practice good riding techniques. so easy to get complacent.
Ted

 

[laker9142]

I have a question about Sag.
Given these two unquestionable facts,
1) you can't change a springs rate.
2) If you put the same weight on the same spring ,it will compress to the same length, every time.
AND, when you turn the so called preload adjusters, all it does is raise or lower the front end. Or stated another way, it lengthens or shortens the fork travel.
So Given all that, how do you change sag?

 

[Steve in sunny Fla]

I have a question about Sag.
Given these two unquestionable facts,
1) you can't change a springs rate.
2) If you put the same weight on the same spring ,it will compress to the same length, every time.
AND, when you turn the so called preload adjusters, all it does is raise or lower the front end. Or stated another way, it lengthens or shortens the fork travel.
So Given all that, how do you change sag?

Actually, when you're doing sag adjustments all you're really doing is raising or lowering the static height of the bike to begin with. This is done to set the loaded sag measurement at apx 30% of the total travel. So let's say you're heavier (me) you will need to crank in more preload to raise the bike unloaded, thereby raising the bike loaded. If after fully preloading the spring you still can't reach that 30% mark (if that's what you were shooting for) then you will need a stiffer spring. Also, if you preload the spring (s) (shock or forks) to the point that you don't have any free sag left (about .5") when the bike is upright and unladen, then you also need a heavier spring. I ran AK20 cartridges and 1.2 springs in the front, and a penske dual adjust shock with a 900# spring. The shock was delivered with a 750# spring, and it sucked. The light spring wouldn't reach the 30% setting and the piston acceleration made the hydraulics stiff. the ride sucked, very harsh. I went up in spring weight until I reached perfection, a 900# spring. the free sag and loaded sag were perfect, and the ride was plush in comparison to the original setup. I learned all this watching you tube video's and reading articles, mostly from Dave Moss. He's a suspension guru.
Steve

 

[laker9142]

So if sag is defined as the amount of movement of the fork from fully extended to the distance moved when sitting on the bike (mine is 39.5mm). Then you can't change it without a spring change, correct? The only thing you can change is ride height, correct?

 

[connie_rider]

Thanx Kuzin Ted. You've started a good discussion.
In your case it seems that the guy first set your ride height and then also adjusted your damping.

I enjoy suspension discussions as I learn so much. It gives me a chance to add to my understanding poor understanding of suspension setting.

Looking at your 2 statement together, I think y'all defined sag (and how it works) well.

I do have 1 thing that I question.
Laker said;
1) you can't change a springs rate.
2) If you put the same weight on the same spring, it will compress to the same length, every time.
On those 2 points I totally agree.

You also sed;
Or stated another way, it lengthens or shortens the fork travel.
I question that.
(Given 1 and 2) I think the area in which the travel happens is raised or lowered, not the amount of travel.

The reason for setting sag. (??)
I think that setting sag is ""not"" done to adjust the stiffness of the ride nor amount of travel.
I think that it is done to adjust the ride height and geometry of the suspension.
ie; Setting the sag adjusts the ride height and geometry of the bike "to the ideal height" for improved handling. It also helps you determine the correct spring.

After the sag is correct, you can move on to setting the damping.

Thoughts?

Ride safe, Ted

 

[laker9142]

You also sed;
Or stated another way, it lengthens or shortens the fork travel.
I question that.

If you turn the adjusters on top if each fork 2 full turns, it increases the distance from the cable tie (around the fork tube, to the btm of the dust seal by 1mm. The cable tie was located at 39.5 mm from the btm of the dust seal, after the initial loading of the bike with my body weight. Now it's at 40.5mm after the 2 turns as previously stated. (Tells me it's a .5mm pitch thread, btw). So, it exposed another mm of fork tube which tells me it now has 1mm more travel.
After that was done, I rechecked sag and it was still 39.5mm, just as before, only 1mm higher on the fork tube.

Edit to note. This whole post is wrong. Including the pitch. which is 1mm. not .5mm.

 

[Steve in sunny Fla]

Laker, you’re correct if getting the ideal sag measurement lifted the bike up. You will get more downward suspension travel until bottoming the suspension.

 

[Steve in sunny Fla]

If you turn the adjusters on top if each fork 2 full turns, it increases the distance from the cable tie (around the fork tube, to the btm of the dust seal by 1mm. The cable tie was located at 39.5 mm from the btm of the dust seal, after the initial loading of the bike with my body weight. Now it's at 40.5mm after the 2 turns as previously stated. (Tells me it's a .5mm pitch thread, btw). So, it exposed another mm of fork tube which tells me it now has 1mm more travel.
After that was done, I rechecked sag and it was still 39.5mm, just as before, only 1mm higher on the fork tube.

So you have about 50% sag?

 

[laker9142]

Using book value of 113 mm total travel, 39.5 mm of sag would be 34%. But I can't reproduce the 39.5mm number. I can reproduce 35mm of sag over and over, which is 30%.

Also, I still get 35 mm of sag regardless of ride height. If sag is defined as Fred said in his PDF, then I don't see how to change it without a spring change. Please correct me if I'm wrong.

 

[Steve in sunny Fla]

Using book value of 113 mm total travel, 39.5 mm of sag would be 34%. But I can't reproduce the 39.5mm number. I can reproduce 35mm of sag over and over, which is 30%.

Also, I still get 35 mm of sag regardless of ride height. If sag is defined as Fred said in his PDF, then I don't see how to change it without a spring change. Please correct me if I'm wrong.

Are you putting a zip tie on the fork, sit on the bike and then centerstand the bike, extending the forks fully and then measuring from the top seal top edge down to the zip tie?

 

[laker9142]

Not exactly but equivalent. Bike is on lift table, front wheel in vise. Scissor jack under oil pan and lifted to the point that rear tire is off ground. Front is fully extended. 12 inch steel scale (graduated every .020inch) cable tied to lower fork leg. Step stool next to the bike so I can get on and off without disturbing the sticktion point. Phone taking video to be sure mounting/dismounting doesnt disturb sticktion point. This way I was able to measure not only the top side of sticktion but bottom side also by giving it one good push on the handle bars and letting the springs push it back up. My hands were on the tank during mount/dismount.Did it all twice at both heights, 2 turns apart, for a total of 4 times. It all averaged out to 35mm from full extention to average amount of sag.

 

[Steve in sunny Fla]

I’m trying but you’re losing me. If you have 35mm , want 39 mm and each turn is .5mm, then back the preload adjuster out 8 turns.

 

[laker9142]

Sorry I got carried away with that explanation. Suffice it to say that I had an accurate, repeatable method to check it by myself.

 

[Steve in sunny Fla]

Sorry I got carried away with that explanation. Suffice it to say that I had an accurate, repeatable method to check it by myself.

I get it. So all said and done, what sag number are you trying to achieve, and what sag # are you getting at max preload? Hint - the bike has 1.2 springs in it, and none of the aftermarket springs to my knowledge are stiffer.

Here's some things that help. the factory number of 113 mm full travel is measured from the bottom edge of the fork tube to the wheel stantion (for lack of a better name). Fred is measuring from the bottom lip of the seal, which in the real world is a much better way to measure, or you're theoretically allowing the seal to be crushed to reach the "book value" . So let's say the the seal is 8mm thick (guess). That reduces the full fork travel to "by the book" to 105mm. Here's what I would suggest... Forget the book value and measure the fully extended fork from the bottom of the seal to the wheel stantion. THIS is your full stroke for the front forks. Now find a percent of that stroke as your TOTAL sag number. Generally it will be 1/3 of the full stroke. If you figure in the seal width and want to get the sag more technically correct, go with 30% of the full stroke. You'll see this lines up closely with Fred's numbers.

Now there are 2 components to sag. there's free sag and rider sag. Free sag is how much the bike compresses the suspension under it's own upright weight. Rider sag is the total sag you get when on the bike. Free sag is very important in this equation. It should be about 1/2" (12 to 13mm). Free sag prevents the bike from fully extending the forks harshly and causing another "bump" to the chassis.

With free sag in mind, here's how the factory "1 spring fits all" fails. If you look at Fred's chart for diffent weight riders, you'll see the heavy rider needed all the preload dialed in, and still had more sag than the other riders. The problem here is that with this rider, the bike is undersprung. with all the preload dialed in, the bike would probably be topped out and have no free sag. The answer here is a stiffer spring and less preload.

If you have the heaviest spring available, of if you're undersprung but don't want to buy more springs, you can also raise the oil level in the fork. This reduces the air volume, and since the air is compressible and fluid isn't, the reduced air volume compresses less. This can also make the fork not bottom so far down, but it can contribute to harshness. This has nothing to do with oil weight, as that's dealing with how much volume can flow through the damper system. In other words, don't think putting a lighter oil in for volume will be softer. It may be in softer damping, but not in the effect it has on the "air spring".

Credit to Dave Moss for my suspension education.

Steve

 

[connie_rider]

I'm baaaackkk. Good discussion. I'm here to add my 2 cents.

I'll start with; Since I know both of you, I know I can say that both of you are on the same page.
It's the explanation and definitions that are causing confusion.

Lets start with; we all agree that;
1) you can't change a springs rate.
2) If you put the same weight on the same spring, it will compress "to" the same length, every time.

NEXT: When the spring is installed in the front forks, it is compressed during the installation.
So when you crank in preload, what you actually do is; you compress the spring more.
Result; If you crank in 10mm the bike sets approx. 10mm higher "and" the loaded sag is decreased approximately the same 10mm.
** This happens because you mechanically compressed the spring 10mm.
ie; The spring thinks you added weight. (because the spring was "pre-loaded" by the 10 mm of compression)

Using Lakers 39.5 mm of loaded sag as a number: {Corrected after Freds info}
(After the pre-load) The bike (with 10 mm cranked in) will still go down 39.5 mm when he sets on it, but the bike will be setting 10 mm higher that it did previously.

NOTE: With him setting on the bike, the compressed length of the spring is still "exactly" the same length as it would have been if he did not crank in 10 mm of preload.
Because;
1) you can't change a springs rate.
2) If you put the same weight on the same spring, it will compress "to" the same length, every time.

(My definitions)
Here I've modified my definition's a bit. Hoping that they may be less confusing. {??}
I'll say that;
Total Travel is all the travel that is available with the forks completely extended.
Available Travel is the amount of Travel available "after" the bike Sags.
Normal Travel is the amount of Travel that is used during normal riding.
Remaining Travel is the amount of Travel that you do not use during normal riding.
NOTE: I used the term Available Travel and Remaining Travel as I don't know the correct name's.

My Statement;
While Riding you Normally use a certain amount of Travel, but you never want to use "all" the Available travel, and you always want some Remaining Travel.

Going a bit further.
Raising the bike 10 mm does "not" increase the amount of travel that you normally use.
Because;
1) you can't change a springs rate.
2) If you put the same weight on the same spring, it will compress "to" the same length, every time.

But; Raising the bike 10 mm "does" increase the amount of Available travel and the amount of Remaining Travel.

The advantage of the (10 mm) increase in Available and Remaining travel is; If you hit a harsher bump, the suspension has another 10 mm of travel available.

For the sake of discussion, I'm using these numbers.
Steve said that the bike has 113 mm of Total Travel.
Laker said that his sag is 39.5 mm.
(Additionally) Let's say that (in normal riding) Laker uses 50 mm of Travel.

Using those numbers;
113 mm - 39.5 mm = 73.5 mm Available Travel
113 mm - 39.5 mm - 50 mm = 23.5 Remaining Travel

With the Available Travel @ 73.5 mm and the Remaining Travel @ 23.5 mm; Cranking in 10 mm of Preload would increase Available Travel to 83.5 mm and Remaining Travel to 33.5 mm.

Lastly: I realize that the numbers I'm using are not correct for 35% sag. I'm just using what numbers were posted to try to explain my thought.
Also; 10 mm of Preload would "not" raise the bike 10 mm (because you're pushing against a spring, not a solid object). I'd guess that 10 mm of Preload would raise the bike approx. 5 to 7 mm.

Ok, y'all know more than me. Am I on the right page?

Ride safe, Ted

 

[laker9142]

First, I want to correct something I said about pitch. It's a 1mm pitch thread not .5mm like I said earlier.
Mine is 15mm total adjustment in 15 turns. (.60 inches)
Also, on mine the sag is 47mm with the adjustor all the way out (full ccw)(15mm showing on the adjustor).
Sag is 34.5 with adjustor all the way in (full cw) (nothing showing above adjustor).
Kinda surprisingly my free sag is only .03 inch (.75mm) above loaded sag.
Ted is correct that I was confused on the word SAG. Always have been, I much prefer to use the term "ride height". It's so much easier for my mind to understand.
I was trying to prove that changing ride height (or sag) has no effect on the spring. And I did as it's a 1 to 1 ratio comparing the adjustor to the change in ride height....BUT NOT as sag is calculated. THIS IS WHAT HAS CONFUSED ME FOREVER!
Changing the adjustor 15mm (from full stop both cw and ccw) equals readings on my scale of 9.57 and 9.00 inch. which is a .57 difference. which is (almost) the 1 to 1 ratio I was referring to.
There isn't any of the adjustor movement going into the spring, only moving the bike up and down on top of the spring.
I'm not sure about some of the stuff Ted said, I'll go back and reread it later. But thanks to Steve and Ted for indulging me.

 

[connie_rider]

I'm learning too. Never thought of suspension this way before.

My definitions;
Ride height is the height of the suspension when you're setting on the bike.
Free Sag is the amount of Travel that was used by the weight of the bike.
Loaded Sag is the amount of Travel that was used when you set on the bike.

Ride safe, Ted

 

[Steve in sunny Fla]

You're both right.

And Laker, if you have 35mm with the adjuster cranked all the way in, and you want the theoretical 39mm loaded sag, then back the preload adjuster out 4 turns. Walla! 39mm total sag, and you added 4 mm to your free sag for a total of 4.75 mm free sag. Not the 12-13mm you should get with the proper spring, but better than what you had.

Steve

 

[Fred H.]

The whole purpose of setting the sag on your suspension is to keep the shock operating in the proper range so that is has both room to extend, and room to compress. If it has too little sag, you can actually top the shock (or forks) out when rebounding, and if it has too much sag you run the risk of bottoming the shock out when it compresses on a large bump.

The 30% number for sag is generally used because the shock needs more room in compression than it does in rebound, so 30% sag gives it about 70% of its total travel available for compression. Spring rates should be selected to try to get you close to that magic 30% range. Also, make note that touring bikes typically use a slightly higher number (around 34%) for loaded sag because of increased weight. And riding two-up changes everything, so you'll obviously need a lot more pre-load added when touring to try to even get close to that number. When I ride two-up fully loaded on a two-week trip, I'm probably closer to 40% (or more) sag.

Increasing or decreasing sag does not impact how much the spring is compressed under load, it just changes "ride height". However, its not as simple as just that. Because ride height (front and rear) change the bikes attitude which impacts a whole host of other dynamics, like center of gravity, and front to rear weight bias, as well as wind dynamics at higher speeds. When you raise the rear of the bike, weight is transferred to the front wheel and vice-versa when you lower the rear (or raise the front). And another thing that is impacted is dampening, because most shocks (and fork internals) do not have linear damping curve throughout their range of travel. As the shock approaches the ends of travel, the damping rates typically go way up. So by just changing "sag" or "ride height" you have impacted much more than just where the bike sits when loaded, as now damping dynamics have been impacted because the shock or forks are operating in a different portion of their travel. And to further complicate things, the rear shock linkage may also be somewhat "progressive" which can have another huge impact depending on the range its operating in.

And as you add rear preload and weight bias moves to the front, then both front and rear damping may need to be reset to account for the reduction in weight on the rear. Rake and trail also are impacted with sag changes, and the bikes "turn-in" feel may become radically different all of a sudden after a simple change to rear preload settings.

Furthermore, there is no perfect setup for a bike, as suspension settings are highly personal, and some folks simply have different preferences or goals for their ride quality. And also keep in mind that the faster your ride, the harder your suspension works, and what may feel great at 40 mph may suddenly feel highly inadequate for triple digit speeds. And attitude starts to play a roll at these higher speeds, as too much front weight bias and too high of a rear end can start to cause tail-wag and can induce a tank-slapper event.

My advice is when you make suspension setting changes, just change one setting at a time, and then go ride it and see what the effect is before making any other adjustments. I like to set my damping adjustments at each extreme and ride it that way (slowly and cautiously) so I fully understand the impacts of what too much and too little damping feels like and how it impacts the ride. Then I put them back where I started and ride it so I can decide if I want more rebound or compression damping.

And if you have a shock that has both high speed and low speed damping adjustments, you're in for even more fun turning knobs. Many times I think shocks with too many adjustments on them just cause more problems than they solve, because owners can easily get into never ending adjustment scenarios, and have even more opportunities to get everything totally out of whack. The term, KISS comes into play here. Less knobs to turn in many cases is actually better.

The article I wrote with suggested settings (below) should give you a good starting point for OEM suspension settings, but you will most likely want to tweak some beyond that to get a ride that suites you and your riding style.

 

[connie_rider]

Fred. Good clarification.
(I think I was close, but with your information; (I realize that I need to modify my earlier post).
Thank you.

As I recall, (after I set mine) I discovered that they were very similar to the numbers you posted for my weight.
(225ish w/gear)

On the front pre-load are you measuring from the bottom of the hex on the adjuster to the top of the hex on the fork cap?
If yes, my current setting is 7.6 mm.
& I think 21 clicks on rear shock.

 

[Fred H.]

Thank you, Fred. Good clarification.
I'll go back and try to find my settings in my notes.
As I recall, (after I set mine) I discovered that they were very similar to what you had posted for my weight.
(225ish w/gear)

On the front pre-load are you measuring from the bottom of the hex on the adjuster to the top of the hex on the fork cap?
If yes, my current setting is 7.6 mm.
& I think 21 clicks on rear shock.

All my measurements go by whats printed in the owners manual.

 

[connie_rider]

Ok, Thank you. That makes my front more like 16 mm.
** May be able to raise the Pre-load/ride height a bit.
Will check my sag when I can.

 

[Steve in sunny Fla]

I’ve been burning hair folicles for the last few days working to understand the effect rocker ratio has on my versys 1000, which has an almost horizontal shock. I’m not an engineer and don’t havy cool software to draw the linkage and force vectors to figure out why my 1100.00 wilbers shock isn’t much better than the stock shock on high speed compression bumps. I’m sure it’s undersprung ( proven by setting sag). I talked to the tech and mentioned free sag, and he says they don’t consider free sag. I know when I applied Moss’ theory to spring selection on my c14, I had to go up 150# on my penske shock the ride quality became amazing, getting the piston where it needed to be. On the V1000 I’meaning towards experimenting with different rocker ratios before i change the spring. It’s nice to be able to use my brain again!

 

[laker9142]

Thanks for the clarification, Fred. I knew most of it, forgot some of it, remembered some of it and learned even more in this thread. My main hang up was the term sag, (as I stated before). To me sag meant to add a load to make it sag more, and I knew that wasn't true. But I realized that sag can also mean simply that something is lower than it was.

But that brings up another terminology question. Why do you think they (meaning almost everybody, including the manual as you have shown} call the ride height adjustor a "spring preload adjustor"? As you (and I, Steve and Ted) have stated earlier, there is no load being applied to the spring by the adjustor, so how do you adjust load if it doesn't exist? Furthermore, the spring is only preloaded one time and that is just to make it fit into a short space as defined by the fork designers. This could better described as precompressed to avoid a lot of misconception. Once the point of precompression is past when compressing the spring with the normal load, then it becomes a moot point. Do you agree? Anybody else?

 

[Steve in sunny Fla]

Thanks for the clarification, Fred. I knew most of it, forgot some of it, remembered some of it and learned even more in this thread. My main hang up was the term sag, (as I stated before). To me sag meant to add a load to make it sag more, and I knew that wasn't true. But I realized that sag can also mean simply that something is lower than it was.

But that brings up another terminology question. Why do you think they (meaning almost everybody, including the manual as you have shown} call the ride height adjustor a "spring preload adjustor"? As you (and I, Steve and Ted) have stated earlier, there is no load being applied to the spring by the adjustor, so how do you adjust load if it doesn't exist? Furthermore, the spring is only preloaded one time and that is just to make it fit into a short space as defined by the fork designers. This could better described as precompressed to avoid a lot of misconception. Once the point of precompression is past when compressing the spring with the normal load, then it becomes a moot point. Do you agree? Anybody else?

to add to the confusion, why do the manufacturers refer to damping in terms of hard or soft? it's neither, it's fast or slow. sheesh... disinformation.

 

[laker9142]

wilbers shock isn’t much better than the stock shock on high speed compression bumps.

I have the 3 way adjustable Penske on the C14. I've adjusted the hi speed a lot and I'm glad to have it. Here's the only thing I know for sure about the high speed valving as it relates to spring stiffness.... When I built my H frame to make the tetra lever system more ridged, I had to soften the hi speed to compensate. My modification was the same as having a stiffer spring because all of that uncontrolled movement in the upper tetra struts was now being absorbed by the suspension. So stiffer spring would mean a need for a, softer to react hi speed valving. (Sorry, even my Penski manual calls it stiff and soft). My GUESS is that you'll have to have it revalved, especially if you go to an even stiffer spring. I am no expert nor an engineer, but thats my story.

 

[Fred H.]

But that brings up another terminology question. Why do you think they (meaning almost everybody, including the manual as you have shown} call the ride height adjustor a "spring preload adjustor"?

Because it is a pre-load adjuster. When the bike is on the centerstand and you turn the adjuster, you are indeed applying more pre-load to the spring because the shock is fully extended and can't extend any further. It's at its limit of travel, so turning the adjuster compresses the spring. Some pre-load is needed on the spring with the shock fully extended for the spring and shock to operate in harmony with each other.

But when the bike is off the centerstand and you are sitting on it, the shock is no longer fully extended so if you apply more preload, it simply extends the shock more.

So in the dynamic mode, it is a ride-height adjuster. But in the static mode it is a preload adjuster. Essentially, it does both.

 

[laker9142]

Faster must be softer? If you blow the valves open faster,(sooner) it would seem softer. Edit; this thought was about hi speed valving. Obviously faster is softer in lo speed mode.

 

[laker9142]

But in the static mode it is a preload adjuster. Essentially, it does both.

I guess that's technically true but I don't ride in the static (centerstand) mode much. Thanks for that, it does explain it. But it's very deceiving for the guy that doesn't understand it.

 

[Steve in sunny Fla]

Because it is a pre-load adjuster. When the bike is on the centerstand and you turn the adjuster, you are indeed applying more pre-load to the spring because the shock is fully extended and can't extend any further. It's at its limit of travel, so turning the adjuster compresses the spring. Some pre-load is needed on the spring with the shock fully extended for the spring and shock to operate in harmony with each other.

So do you disagree with Moss’ assertion that the bike needs apx 13 mm free sag ? His method doesn’t push the suspension to the limits of its travel. This really means the spring rate has to correct to reach free sag and loaded sag numbers correctly.

 

[Steve in sunny Fla]

Here's an article from Motool that explains the relationship of static (free) sag, rider sag, spring rate and preload.

Why Static Sag Is So Important

You have probably noticed whenever you see references to sag you will see both static sag and rider sag. Sometimes you will hear to them referred to free sag and race sag depending on the source. Static, or free sag is the amount the suspension compresses from fully unloaded under the bike's own...

motool.co

 

[redline]

Wow I was gone to durango colorado for 4 days and look at all that happened here. Thanks for all your input. This really does take a bit to wrap your head around but after all these posts sure makes a lot more sense. In essence that is what this guys did for me is to "raise" up the bike a bit but also said that before his adjustments the bike's front and rear weren't in sync for lack of a better word. so the front dropped more than the rear of the bike which was also adding to my "problems".

 

[laker9142]

"Static, or free sag is the amount the suspension compresses from fully unloaded under the bike's own weight" (Quote from Motool).

But in the static mode it is a preload adjuster

Terminology strikes again.

 

[connie_rider]

So do you disagree with Moss’ assertion that the bike needs apx 13 mm free sag ? His method doesn’t push the suspension to the limits of its travel. This really means the spring rate has to correct to reach free sag and loaded sag numbers correctly.

I agree that spring rate has to be correct to reach free sag and loaded sag numbers correctly.
But. I think having the correct Loaded sag will also give you the proper amount of Free Sag.

If the spring is sized correctly, you will have the correct Static sag, and the correct Loaded sag.
You will have some adjustability remaining to increase/decrease Pre-load/Ride height)
** Ideally the adjuster will be near the center of its range.

But;
If the spring is sized incorrectly (too soft), you will have too much Static sag, and Loaded sag.
With the adjuster cranked fully in you won't have any adjustability remaining to increase Pre-load/Ride height.

If the spring is sized incorrectly (too hard), you will not have enough Static sag, nor Loaded sag.
With the adjuster cranked fully out you won't have any adjustability remaining to decrease Pre-load/Ride height.

Ride safe, Ted

 

[Steve in sunny Fla]

But;
If the spring is sized incorrectly (too soft), you will have too much Static sag, and Loaded sag.
& (With the adjuster cranked fully in) you won't have any adjustability remaining to increase Pre-load/Ride height.

Or you can have no static sag and still have to much loaded sag. It’s in the article and i’ve experienced it. In fact If you refer to Freds article, I’m sure that’s the case with the 314# rider setup.

 

[connie_rider]

On Freds chart, he has OEM Springs in the bike.
We know the OEM springs are too soft for a 314# rider.
He didn't give a free sag number, but I suspect with all the pre-load cranked in, it may be less than ideal, but not zero.

I do believe what you're saying & trying to reason it out...
Reasoning it out with the knowns;
* No free sag {seems to be too hard of spring}.
** Too much loaded sag {seems to be too soft of spring}.
You said that you have too much Loaded sag but the Free sag is zero.
*** Those 2 tell me that your Loaded sag is longer than normal. {I think that indicates too soft of spring}.

OK: Making a wild A____/calculated guess;
I think that the main spring is too soft for the rider's weight, "and" the topping spring is too soft to work with a main spring that is considerably stronger.

My guess;
Add "both" a stiffer (or possibly shorter) main spring and a stiffer (or possibly longer) topping spring.
With a little matching, the combination could set the balance right. {??}

Ride safe, Ted

 

[Steve in sunny Fla]

On Freds chart, he has OEM Springs in the bike.
We know the OEM springs are too soft for a 314# rider.
He didn't give a free sag number, but I suspect with all the pre-load cranked in, it may be less than ideal, but not zero.

I do believe what you're saying & trying to reason it out...
Reasoning it out with the knowns;
* No free sag {seems to be too hard of spring}.
** Too much loaded sag {seems to be too soft of spring}.
You said that you have too much Loaded sag but the Free sag is zero.
*** Those 2 tell me that your Loaded sag is longer than normal. {I think that indicates too soft of spring}.

OK: Making a wild A____/calculated guess;
I think that the main spring is too soft for the rider's weight, "and" the topping spring is too soft to work with a main spring that is considerably stronger.

My guess;
Add "both" a stiffer (or possibly shorter) main spring and a stiffer (or possibly longer) topping spring.
With a little matching, the combination could set the balance right. {??}

Ride safe, Ted

Spring is to soft.

 

[Motomaniac]

My 2008 the rear shock adjusting knob does not click anymore. I am pretty happy where the setting is at now. OEM Shocks front and rear. 172K miles on the bike. I am sure I read somewhere that you can repair the shock adjuster so it does click. Should I really worry about it? I weigh 240 pounds. Front adjusting works just fine.

 

[Steve in sunny Fla]

G

My 2008 the rear shock adjusting knob does not click anymore. I am pretty happy where the setting is at now. OEM Shocks front and rear. 172K miles on the bike. I am sure I read somewhere that you can repair the shock adjuster so it does click. Should I really worry about it? I weigh 240 pounds. Front adjusting works just fine.

Generally spraying some wd40 or even silicone lubricant up under the adjustment handle onto the shaft and working the knob will free it up.

 

[Motomaniac]

G

Generally spraying some wd40 or even silicone lubricant up under the adjustment handle onto the shaft and working the knob will free it up.

Thank you!

 

[laker9142]

Here's an article from Motool that explains the relationship of static (free) sag, rider sag, spring rate and preload.

Why Static Sag Is So Important

You have probably noticed whenever you see references to sag you will see both static sag and rider sag. Sometimes you will hear to them referred to free sag and race sag depending on the source. Static, or free sag is the amount the suspension compresses from fully unloaded under the bike's own...

motool.co

I've read this several times in the last couple of days and I think they are flawed in their thinking, or at least misleading and confusing.

Here is a quote from them,,,,,,,,,"If you barely have to preload the spring to get the rider sag correct, when the rider dismounts, the spring will not hold the bike all the way up because it barely has any preload on it, so you get a static sag reading that is bigger than the recommended range".

Even if you substitute "ride height adjustment" for "preload the spring" it still doesn't work. They are implying that the adjustor has an effect on the spring. This is internet drivel that pushes a false premise like so many other internet experts. I wouldn't normally care about drivel, but I know people get confused and don't know what to believe. So, I'm going to give you an example that eliminates "preload" altogether.

*Eliminating the notion of "preload."'
*First of all, it only exists on the bench, or with the tire off the ground, making it meaningless.
*I can easily make a cutaway version of an upper fork tube to prove this. So first imagine a cutaway window in the upper fork tube, exposing the spring.
*Measure the spring length at full load through the window (and for fun measure the "preloaded" length).
*Now weld on a 4" extension to the top of the fork tube. The 4" extension will be above the upper triple clamp. The spring will be at full length, plus it will be free to rattle up and down. This eliminates the notion of "preload."
*Now measure the spring at full load, it will be the same as it was with "preload". Also, the preloaded length that we measured for fun will not exist.

Remember that the,,,,same weight on the same spring will compress it to the same length every time.
Any comments?

 

[Steve in sunny Fla]

I've read this several times in the last couple of days and I think they are flawed in their thinking, or at least misleading and confusing.

Here is a quote from them,,,,,,,,,"If you barely have to preload the spring to get the rider sag correct, when the rider dismounts, the spring will not hold the bike all the way up because it barely has any preload on it, so you get a static sag reading that is bigger than the recommended range".

Even if you substitute "ride height adjustment" for "preload the spring" it still doesn't work. They are implying that the adjustor has an effect on the spring. This is internet drivel that pushes a false premise like so many other internet experts. I wouldn't normally care about drivel, but I know people get confused and don't know what to believe. So, I'm going to give you an example that eliminates "preload" altogether.

*Eliminating the notion of "preload."'
*First of all, it only exists on the bench, or with the tire off the ground, making it meaningless.
*I can easily make a cutaway version of an upper fork tube to prove this. So first imagine a cutaway window in the upper fork tube, exposing the spring.
*Measure the spring length at full load through the window (and for fun measure the "preloaded" length).
*Now weld on a 4" extension to the top of the fork tube. The 4" extension will be above the upper triple clamp. The spring will be at full length, plus it will be free to rattle up and down. This eliminates the notion of "preload."
*Now measure the spring at full load, it will be the same as it was with "preload". Also, the preloaded length that we measured for fun will not exist.

Remember that the,,,,same weight on the same spring will compress it to the same length every time.

Funny, I just went through exactly this with Mike Dionne. I'll try here. 1) you're correct, regardless of preload, the spring will compress to the same weight at the same distance every time. We'll need a little math here. Let's say the spring is 1"/100# and it's 3" fully compressed travel, from zero to coil bind is 3". Each .100" = 10#. Now we need to hold up 60#. this would equal .600" spring compression. BUT we want to leave some room (free sag) for the shock to compress to reach the 60# we need to hold the bike up. So we dial in .500" spring compression (50# preload) and the spring compresses under the weight of the bike another .100" (free sag) to reach that 60# force we needed. We have used .600" of the total 3" spring travel, have the bike lifted all the way up except for the free sag.

Now let's add another weight, we'll call it the mini-rider. His weight is 30#. The spring will compress another .300" under his weight. The preload plus the minirider weight = 80#. But total force needed is 90#. Now we're holding the 90# with 1/10" free travel up with a TOTAL spring compression of .9" . There's 3.10" of travel left in the shock.

Now let's assume this gives us the sag we want. We're right in the ballpark of 1/3" rider sag. Everything is good.

But let's say the mini-rider weighs 60#. Now the total weight to hold up is going to be 120#. That would mean a total spring compression travel from zero compression would be 1.2". With the same spring, you're going to have to "preload" the spring another .400" (40#)to a total 90# to have the same rider height as the first scenario. OK, we can do that. let's crank up the preload. GREAT! Now the rider height is back! We have all 120# force needed accounted for!

Unfortunately the law of unintended consequences raises it's head.... now when you get off the bike it tops out, there's no free sag left. Not only is it gone, but you need to add another 30# force to the spring just to get it to START to get the piston compress. Remember, you had 50# force from spring preload and then another 10# force from spring compression to reach 60# . Now you have 50#+40#=90# preload to hold up something that weighs 60#. You have .900" preload, and only .300"spring travel to hold up the 120#. Your rider sag is where it should be, but when you get off the bike it's topped out hard.

Preload... spring force you'll never use again. it's working at it's full potential.

Keep thinking. in terms of how much does 1" travel equal, how much does .100" travel equal, and how much weight or force is being applied.

Trust me, this all gets worse on the bike when we consider front / rear weight bias and rocker ratios.

Steve

 

[connie_rider]

Because it is a pre-load adjuster. When the bike is on the center-stand and you turn the adjuster, you are indeed applying more pre-load to the spring because the shock is fully extended and can't extend any further. It's at its limit of travel, so turning the adjuster compresses the spring. Some pre-load is needed on the spring with the shock fully extended for the spring and shock to operate in harmony with each other.

But when the bike is off the center-stand and you are sitting on it, the shock is no longer fully extended so if you apply more preload, it simply extends the shock more.

So in the dynamic mode, it is a ride-height adjuster. But in the static mode it is a preload adjuster. Essentially, it does both.

Feds post explains that the adjuster is both a preload adjuster and a ride height adjuster.

NOTE: The accepted name for the adjuster is the Pre-load Adjuster.
{Even though it's normal use is for Ride height adjustment}.

We're back to; It's the explanation and definitions that is causing confusion.

I think all of us agree on what happens when the adjuster is screwed down or up.
Below I made several statements. Read them and let me know if you agree?

Pre-load/Static; With the wheel off the ground, screwing the adjuster down 1" will compress the spring 1".
At that time (only), 1" of adjustment applies additional force/pre-load to the spring.

Ride-height/Dynamic; As you stand the bike up the pre-load force disappears.
The bike stops going down when the spring is compressed enough to support the weight of the bike.
NOTE: The spring stops compressing at the exact same height it would have, if you did not screw the adjuster down 1".

The difference is; the bike's Ride-height is 1" taller than it would have if you had not screwed the adjuster in 1".

Ride safe, Ted

 

[redline]

so hopefully now that my height was adjusted i have a bit more play with my lean angle. so this was quite a learning curve. so does anybody might want to comment on how to properly adjust the front and rear so you don't have either react differently etc.

 

[laker9142]

Ted gets it. But the thing about preload with the tire off the ground is meaningless as soon as the bike hits the ground. Ill have to digest Steves explanation.

 

[Steve in sunny Fla]

Ride-height/Dynamic; As you stand the bike up the pre-load force disappears.
The bike stops going down when the spring is compressed enough to support the weight of the bike.

Pre load force never disappears. It's part of the overall total spring compression needed to support the weight of the bike / rider / load.

Check my math. Yes, it's a pita, but the numbers don't lie.

Steve

 

[Steve in sunny Fla]

Ted gets it. But the thing about preload with the tire off the ground is meaningless as soon as the bike hits the ground. Ill have to digest Steves explanation.

Nope. Check my math. With your background the math will set you free!

Steve

 

[Steve in sunny Fla]

Just funnin'!

 

[laker9142]

I think we are agreeing on some stuff. But you are adding in variables that don't matter to setting the ride height on a Concours for the rider/owner. You also want to keep using the term "preload" which is a misnomer and confusing because people associate preload with adding spring load. (Although that is the common term, and I will just have to accept it). The only way to add spring load is to add weight to the rider which will compress the spring further, AND THEN you would turn the adjustor to bring the ride height back to where it was. Turning the adjustor did not add the load, the HEAVIER RIDER did. (But that hasn't been a part of this discussion until now).

I also don't pay any attention to free sag. On my bike and I assume others with 1.2kg/mm springs, you set the rider sag and the free sag is what it is, you can't change it. In my case there was only .75mm (.030") difference. Thats with the proper spring as supplied by Traxxion.

BUT we want to leave some room (free sag) for the shock to compress to reach the 60# we need to hold the bike up. So we dial in .500" spring compression (50# preload) and the spring compresses under the weight of the bike another .100" (free sag) to reach that 60# force we needed.

This is hard to understand^^^. Seems mysterious to lose or gain 10 lbs. Again, once you set the rider sag, the free sag is what it is.
I feel like you're making this much more difficult than it really is. Some of that free sag consideration might make a difference to a real racer, but not in Cogdom. And people still don't know who or what to believe. It's really very simple and illustrated perfectly in my "eliminating the notion of preload" post #46, hopefully the folks can work through this on their own. But I suspect most Concours riders don't really care to understand and will refer back to Freds chart, which is great, thanks to Fred. Thats pretty much all I can say about. And I do enjoy the back and forth and sharing of ideas.

 

[connie_rider]

Pre load force never disappears. It's part of the overall total spring compression needed to support the weight of the bike / rider / load.

Check my math. Yes, it's a pita, but the numbers don't lie.

Steve

I just got back and trying to write my thoughts better.

(Disappears) I'm not using the correct word.
I do not think that cranking in 1" of adjustment adds additional force when the weight of the bike is on the spring.
Trying to reason out what is happening. Dayummm, this is hard!

I'll have to do some assumptions and basic math to show my reasoning.
Assume;
** When fork tube is assembled; the assembly puts 100# of force on the spring.
** When the adjuster is screwed in 1" you add 50# of additional force on the spring.
So, (wheel off ground you have 100# and with 1"/50# of adjustment added you have 150# of force on the spring. (100# + 50# = 150#)

Now, (for sake of clarity) with the wheel still off the ground, remove the 1"/50# adjuster adjustment and you return to the original 100# of force on the spring. (150# - 50# = 100#)

** Let's assume that when you take the bike off the center stand the front end weight puts 200# of force on the spring.

Now, take the bike off the center stand and stand the bike up.
The spring is now seeing the 100# of the assembly Preload, and the 200# of weight.
Together you now have 300# of force on the spring. (100# + 200# = 300#)
At this point, the compressed spring is seeing 300# of force and the front of the bike will go down until the spring supports the 300 # of load. (Lets say the bike went down 3" when the bikes weight was added).

Next; Crank in 1" of adjustment.
** Previously (when the adjuster was screwed in 1" you added 50# of force to the spring).
But, with the bikes weight on the spring, and 1" adjustment is cranked in; this does not happen.
I'm saying that the compressed spring will not compress further when you crank in 1" of adjustment.
(ie; The 50# of pre-load does not happen).

"Instead" the front of the bike will rise 1".
The spring stays at exactly the same spot as it was before you cranked in the 1".
But the front of the bike rose 1".
This shows that the force on the spring remained at 300#. (Did not increase by 50# to 350# of force),
ie; The pre-load became ride height-adjustment and "no" Pre-load force was added to the spring.

Thoughts??

Ride safe, Ted

 

[Steve in sunny Fla]

Laker, , ok I’ll stand down and Im out. Bot if you want to actually understand, the math will set you free.

 

[connie_rider]

Don't go. I'm not arguing. I'm trying to understand this.
I'm looking at your math and something isn't reaching me.

Read mine. Am I incorrect?
If yes, what did I say incorrectly?

Ride safe, Ted

I just realized another way to explain why the adjustment changes from Pre-load to ride height.

With the wheel off of ground / fork is fully extended;
So the 1" of adjustment has to push down on the spring /increase force ""because the fork tubes cannot move out further"". (Pre-load increases)

With the wheel on ground / fork is partially compressed;
So the 1" of adjustment moves the bike up and does not compress the spring further. ""because the fork tubes "can" move up/out further"". (Ride height changes)

NOTE: The springs are already supporting the weight of the bike.
1) you can't change a springs rate.
2) If you put the same weight on the same spring, it will compress "to" the same length, every time.

 

[Steve in sunny Fla]

I've read this several times in the last couple of days and I think they are flawed in their thinking, or at least misleading and confusing.

Here is a quote from them,,,,,,,,,"If you barely have to preload the spring to get the rider sag correct, when the rider dismounts, the spring will not hold the bike all the way up because it barely has any preload on it, so you get a static sag reading that is bigger than the recommended range".

I know I said I'd go, but I seem drawn to this like a fly to a corpse (euuuu) .

That quote is absolutely correct.

When the light bulb turns on, it all makes sense. until that happens, it's internet drivel. But that's written by the company that makes the "slacker" preload tool, so I hope they have a clue.

What the quote didn't include was the length of the spring and the length of suspension travel. With those in mind, read that quote again.

Just FYI, I'm not limiting my comments only to a concours with stock suspension. I'm looking at the entire concept of spring weight / rate / and preload. so once it's understood you could carry what you know to any bike and get it right.

ETA: I talk about the light bulb turning on because that's exactly how it was for me. I wallowed in failure to understand for a long time, but then the bulb turned on, and it all made sense.

Steve

 

[Steve in sunny Fla]

I just got back and trying to write my thoughts better.

(Disappears) I'm not using the correct word.
I do not think that cranking in 1" of adjustment adds additional force when the weight of the bike is on the spring.
Trying to reason out what is happening. Dayummm, this is hard!

I'll have to do some assumptions and basic math to show my reasoning.
Assume;
** When fork tube is assembled; the assembly puts 100# of force on the spring.
** When the adjuster is screwed in 1" you add 50# of additional force on the spring.
So, (wheel off ground you have 100# and with 1"/50# of adjustment added you have 150# of force on the spring. (100# + 50# = 150#)

Now, (for sake of clarity) with the wheel still off the ground, remove the 1"/50# adjuster adjustment and you return to the original 100# of force on the spring. (150# - 50# = 100#)

** Let's assume that when you take the bike off the center stand the front end weight puts 200# of force on the spring.

Now, take the bike off the center stand and stand the bike up.
The spring is now seeing the 100# of the assembly Preload, and the 200# of weight.
Together you now have 300# of force on the spring. (100# + 200# = 300#)
At this point, the compressed spring is seeing 300# of force and the front of the bike will go down until the spring supports the 300 # of load. (Lets say the bike went down 3" when the bikes weight was added).

Next; Crank in 1" of adjustment.
** Previously (when the adjuster was screwed in 1" you added 50# of force to the spring).
But, with the bikes weight on the spring, and 1" adjustment is cranked in; this does not happen.
I'm saying that the compressed spring will not compress further when you crank in 1" of adjustment.
(ie; The 50# of pre-load does not happen).

"Instead" the front of the bike will rise 1".
The spring stays at exactly the same spot as it was before you cranked in the 1".
But the front of the bike rose 1".
This shows that the force on the spring remained at 300#. (Did not increase by 50# to 350# of force),
ie; The pre-load became ride height-adjustment and "no" Pre-load force was added to the spring.

Thoughts??

Ride safe, Ted

OK, let's apply the math. It all starts with the info you had about the preload adjuster compressing the spring 1" and that added 50# force. So the spring rate is 1"=50# .

You stated that the assembled fork caused the spring to return 100# force. at 1"=50#, that would be 2" spring compression.

Screw the preload adjuster down 1" . Now you have 150# spring force keeping the assembled fork at it's full FIXED extended length, and the spring is compressed 3". This is in the fork, even off the bike, laying on the bench. THIS IS PRELOAD.

The front of the bike weighs 200# (for our purposes we'll agree this bike has only 1 fork with the math currently in play). We rock the bike off the c'stand onto the front tire, and 200# force is applied. The spring will compress another 1" (1"=50#) and now the bike is supported by the compressed fork assembly. The fork is providing 200# force to hold the bike up, and it has just begun to hold the weight of the bike with 1" sag, but has 4# spring compression.

The next step in understanding would be to consider the total fork stroke, and the %age of sag you want with the rider weight. I'll leave that for later in the discussion.

Steve

 

[laker9142]

The front of the bike weighs 200# (for our purposes we'll agree this bike has only 1 fork with the math currently in play). We rock the bike off the c'stand onto the front tire, and 200# force is applied. The spring will compress another 1" (1"=50#) and now the bike is supported by the compressed fork assembly. The fork is providing 200# force to hold the bike up, and it has 1" SAG, but has 4" spring compression.

I'm glad to see you've come around. The only thing Ill add is that the spring would have compressed to the same height regardless of the "preload applied". If you read my post #46 you'll see that the concept of preload can be eliminated. You can actually ride the bike with the 4" extended fork tube and you won't know the difference, until you gas it up and pass the point where the damper rod topped out and limited extension. But if you put in a 10hp motor in the C14 you can't overcome gravity and the fork/spring would perform as usual. (In harmony )

This what I was going to write before your last post:
Considering my post 46 and eliminating the notion of "preload". Which can't be argued because I can produce a working model of it. Please explain to me the change in spring length (load) as you do all your mathematical manipulations. Remember you can see and measure the spring as load is affected.

 

[Steve in sunny Fla]

I'm glad to see you've come around. The only thing Ill add is that the spring would have compressed to the same height regardless of the "preload applied". If you read my post #46 you'll see that the concept of preload can be eliminated. You can actually ride the bike with the 4" extended fork tube and you won't know the difference, until you gas it up and pass the point where the damper rod topped out and limited extension. But if you put in a 10hp motor in the C14 you can't overcome gravity and the fork/spring would perform as usual. (In harmony )

This what I was going to write before your last post:
Considering my post 46 and eliminating the notion of "preload". Which can't be argued because I can produce a working model of it. Please explain to me the change in spring length (load) as you do all your mathematical manipulations. Remember you can see and measure the spring as load is affected.

Ok, I get it BUT you’re still failing to consider that you don’t have unlimited fork travel . So let’s say we have everything the same as above, but the fork has 4” total travel, and the spring, fully extended, extends the fork fully but will impart no force when both are fully extended. To reach the 200# force needed to hold the bike up, the fork tube will be completely compressed. Thats not going to work.

 

[laker9142]

Ok, I get it

Good, people believe what you say so I wanted to make it clear. And I mostly believe what you say, but you do make it difficult. I went through this with Ted a couple years ago and that took weeks of pm's for him to come around. He also said not to bring it up on the forum unless I wanted to be tied to the keyboard. But it's fun to have cordial arguments, and I would have said the same had you proven you're point to me.

To reach the 200# force needed to hold the bike up, the fork tube will be completely compressed. Thats not going to work.

Well Ted was talking about a hypothetical scenario. If you're saying that you run out of travel using these parameters in a real situation, then you are correct.

 

[Steve in sunny Fla]

Good, people believe what you say so I wanted to make it clear. And I mostly believe what you say, but you do make it difficult. I went through this with Ted a couple years ago and that took weeks of pm's for him to come around. He also said not to bring it up on the forum unless I wanted to be tied to the keyboard. But it's fun to have cordial arguments, and I would have said the same had you proven you're point to me.


Well Ted was talking about a hypothetical scenario. If you're saying that you run out of travel using these parameters in a real situation, then you are correct.

Slick laker, but you forgot the BUT… and that where the idea of preload lives. In my scenario 25% of the fork travel is used; in yours 100% of the fork travel is used. Which bike would you prefer to ride??? ETA : and NOBODY should listen to me!

 

[connie_rider]

OK, let's apply the math. It all starts with the info you had about the preload adjuster compressing the spring 1" and that added 50# force. So the spring rate is 1"=50# .

(Agree)

You stated that the assembled fork caused the spring to return 100# force. at 1"=50#, that would be 2" spring compression.

(Agree)

Screw the preload adjuster down 1" . Now you have 150# spring force keeping the assembled fork at it's full FIXED extended length, and the spring is compressed 3". This is in the fork, even off the bike, laying on the bench. THIS IS PRELOAD.

(Agree)

The front of the bike weighs 200# (for our purposes we'll agree this bike has only 1 fork with the math currently in play). We rock the bike off the c'stand onto the front tire, and 200# force is applied. The spring will compress another 1" (1"=50#) and now the bike is supported by the compressed fork assembly. The fork is providing 200# force to hold the bike up, and it has just begun to hold the weight of the bike with 1" sag, but has 4# spring compression.

(Doing math and thinking)
Ahh, I just saw where you included "the bike now has 1" of sag".
So, (Agree) But want to add something.

Something;
If we remove the 1" of adjustment (50#), the bike will sag another 1", but the spring will not extend 1".
(because the 200# bike is still being supported by the compressed fork assembly).
The fork Spring is providing 200# force to hold the bike up, and it is now holding the weight of the bike, but we now have 2" sag, and we still have 4" spring compression.

If we add the last 1" of adjustment (50#), the bike rises 1", but the spring will not extend 1".
(because the 200# bike is still being supported by the compressed fork assembly).
The fork Spring is providing 200# force to hold the bike up, and it is now holding the weight of the bike, but we now have 0" sag, and we still have 4" spring compression.

So (using the 1" adjustment = 1" sag movement numbers) our current Free sag range is from 0" to 2".

Something else; The numbers I'm using are made up numbers that I used from the previous discussion.
ie; I didn't think deeply about the ideal numbers, just picked some that worked well in the discussion.
The 1" adjustments we are doing will not raise or lower the bike a full 1" (because the spring is not a solid) but 70% of the 1" may be possible. (??)

NOTE: Earlier;
Laker said that the manual shows we have 113 mm (4.45") of Total Travel.
Steve said that we want about 1/2" (12.7 mm) of Free Sag.
& Our Target is 30% of 113 mm Rider Sag which would be roughly 38 mm (1 1/2").

So (using the 1" adjustment = 1" sag movement numbers) {And adding a second fork tube}
I think our current Free sag range would change to 0" to 1".
So, I think this makes our number choices pretty close. {??}


The next step in understanding would be to consider the total fork stroke, and the %age of sag you want with the rider weight. I'll leave that for later in the discussion.
(Agree)

 

[Steve in sunny Fla]

Ted, If you back off the 1” from the preload adjuster, the bike will drop another inch, using 2” of your stroke, agreed. If you screw the 2” long backed out adjuster down 2” you’ll have zero stroke used and 200# preload on the spring, matching the weight of the bike. So yes, I agree with you in that. The part that seems to be lost in all this is that the stroke length of the fork or shock is fixed, and we have to pick a spring that will provide the right sag and force needed within this stroke. We dont have the luxury of unlimited length springs and unlimited stroke forks or shocks. And let me reiterate- nobody should pay attention to what I say!

 

[connie_rider]

The next step in understanding would be to consider the total fork stroke, and the %age of sag you want with the rider weight.

I'm gonna bring this up now while I'm thinking about it.

** Lets assume that the Rider weighs 200#.
That would add 100# of force to the front forks.
100# of force would further compress the (50# per inch) spring another 2".

Going back to Steves previous statement (with 1" pre-load adjustment cranked in).

The front of the bike weighs 200# (for our purposes we'll agree this bike has only 1 fork with the math currently in play). We rock the bike off the c'stand onto the front tire, and 200# force is applied. The spring will compress another 1" (1"=50#) and now the bike is supported by the compressed fork assembly. The fork is providing 200# force to hold the bike up, and it has just begun to hold the weight of the bike with 1" sag, but has 4" spring compression.

Add the 100# rider load; (2" more compression) and (I think) his statement changes to:
The front of the bike with rider now weighs 300# (for our purposes we'll agree this bike has only 1 fork with the math currently in play). We rock the bike off the c'stand onto the front tire and the rider gets on the bike, and 300# force is applied. The spring will compress another 1" (1"=50# because of the 1" adjustment) (and another 2" from the rider weight) and now the bike and Rider is supported by the compressed fork assembly. The fork is providing 300# force to hold the bike up, and it is holding the weight of the bike and the Rider with 3" sag, but has 6" spring compression.

(We know that 3" sag is too much)
Because; Our Target is 30% of 113 mm Rider Sag which would be roughly 38 mm (1 1/2").

Brings us to;
So (using the 1" adjustment = 1" sag movement numbers) {adding a second fork tube and a Rider}
I think our current Loaded sag would change from 3" to 1 1/2"
So, I think this makes our spring force number choices pretty close. {??}

Ride safe, Ted ( Mad Scientist laugh)

 

[connie_rider]

 

[Steve in sunny Fla]

You’re killin’ it Ted!

 

[Steve in sunny Fla]

Because; Our Target is 30% of 113 mm Rider Sag which would be roughly 38 mm (1 1/2").

Brings us to;
So (using the 1" adjustment = 1" sag movement numbers) {adding a second fork tube and a Rider}
I think our current Loaded sag would change from 3" to 1 1/2"
So, I think this makes our spring force number choices pretty close. {??}

Ride safe, Ted ( Mad Scientist laugh)

Agreed with all of it, you just HAD to add in the other fork, didn’t you!! Now just to put a point on it, the stock springs are 1.2kg/mm. This would be a 57# spring … and the free sag and loaded sag are about what we would want in a concours.

 

[connie_rider]

Woo hoo!!

Ride safe, Ted

PS: Can we talk about Damping next?

 

[laker9142]

and NOBODY should listen to me!

PS: Can we talk about Damping next?

A bunch of comedians!

I'm not saying anymore because you guys are making my eyes go crossed (Ted)

 

[Steve in sunny Fla]

A bunch of comedians!

I'm not saying anymore because you guys are making my eyes go crossed (Ted)

I’m sitting with a sick friend for the last couple days. I appreciate the entertainment and forcing me to use my noodle. Steve

 

[laker9142]

But that's written by the company that makes the "slacker" preload tool, so I hope they have a clue.

I'm still wondering about this Motool company. I believe they're misguided. But Many internet experts are either just wrong or at least very unclear about the subject.

I appreciate the entertainment and forcing me to use my noodle. Steve

Same.

 

[Steve in sunny Fla]

I'm still wondering about this Motool company. I believe they're misguided. But Many internet experts are either just wrong or at least very unclear about the subject.

Same.

Do you want me to explain the slacker comment on the stiff spring? That way I can be misguided / wrong too. It wouldn't be the first time. Ready?

 

[laker9142]

As a result, when the rider dismounts, the spring has so much preload on it that it pushes the shock or fork way back up in the stroke making the amount the suspension compresses under the bikes weight minimal,

This is a very misleading statement. I do agree that the spring will push the bike up too far if the spring is too soft because in order to achieve the proper ride height you had to crank the adjustor down a bunch.

Firstly as you know, i dont like the word preload and the spring has no extra load on it from all the "preload " as stated just after the 2nd comma.

And I have no idea what they mean with the statement that starts with "making the amount" NVM, I get it now..long winded way to say reduces sag.

Please explain and tell me if you think it's confusing to the casual reader.

 

[laker9142]

Also you are better read than I am on all this stuff.
Why is my free sag the same as my loaded sag?
What is the proper range of free sag above the loaded sag?

 

[Steve in sunny Fla]

Please explain and tell me if you think it's confusing to the casual reader.

You gotta be kidding… this is confusing even when you “get it”. The problem is we’re shooting at a moving target - the spring compresses, there’s limited compression of the fork or shock, etc. l’ll address the question tomorrow, got stuff to do this evening.

 

[connie_rider]

What is the proper range of free sag above the loaded sag?

I'll take a stab at that one.

Free sag is the weight of the bike compressing the spring.
In the discussion Steve said that 1/2" was the Target for the Free Sag.
That 1/2" calculates out to roughly 9% of the available Travel. (113 mm / 4.45")

Adding the weight of the bike (200#) would compress the spring 4", (50# per inch x 4 = 4")
But 3" (Of those 4") were already used by the assembly of the fork and the 1" adjustment we had cranked in.
ie; The assembly compresses the spring 2" and we were using 1" of Adjustment. (2" + 1" + 3").

In the discussion we had too much sag. (@1")
BUT: we were talking about only 1 fork tube in the discussion.
So I changed to 2 fork Tubes to see what would happen & 2 Fork Tubes would reduce that 1" Free Sag to 1/2". (which is ideal)

Ride safe, Ted

 

[laker9142]

As a result, when the rider dismounts, the spring has so much preload (added ride height) on it that it pushes the shock or fork way back up in the stroke

As a side note, I used to use this scenario when I was racing sprint cars on dirt. As the track got slicker, we would change to a lighter spring in the front for better weight transfer to the rear, because the front would come up higher. But we used different terms, like ride height and softer springs. Haha, it's so much easier to understand that way. Of course, you had to inherently understand that a softer spring would be compressed more than the heavier spring, thus requiring more ride height to get back to where you were.

 

[kzz1king]

Also you are better read than I am on all this stuff.
Why is my free sag the same as my loaded sag?
What is the proper range of free sag above the loaded sag?

I dont know but I can tell the difference in sag by adding 30 lbs of camping gear on the pillion.

 

[Steve in sunny Fla]

I've read this several times in the last couple of days and I think they are flawed in their thinking, or at least misleading and confusing.

Here is a quote from them,,,,,,,,,"If you barely have to preload the spring to get the rider sag correct, when the rider dismounts, the spring will not hold the bike all the way up because it barely has any preload on it, so you get a static sag reading that is bigger than the recommended range".

Even if you substitute "ride height adjustment" for "preload the spring" it still doesn't work. They are implying that the adjustor has an effect on the spring. This is internet drivel that pushes a false premise like so many other internet experts.

OK, I said I would explain this so here we go. AND since I shot my keyboard off and stated "the math will set you free" I'm going to do it with math.

Since we already went through the scenario Ted layed out of 1"= 50# spring; 2" spring compression = 100# force from compressing the spring to get it in the fork; preload adjuster screwed down 1” to add 50#and 1” sag to hold the weight of the bike with 1” sag; 200# bike and 100# rider = 3" spring preload, 1" static sag + 2" rider sag = 3" total sag and we know that works, let's use that same formula.

This time the rider will be 50#.

So we still need 4" spring compression to provide 200# force to hold up the front end of the bike. We got that with 3" preload and 1" sag. Now we add a light, 50# rider. He compresses the spring another 1". Now we have 2" total sag. But we need 3" sag. So we screw the adjuster out 1" to drop the bike 1" and now the rider has the proper 3" rider sag. There's 5" total spring compression.

Now the rider dismounts, and we have the bikes 200# on the spring, 100# from the spring preload and 100# from compressing the spring 2", which is now the static sag.

The end result is a spring that has 2" static sag (way to much) and yet a total rider sag of 3".

Multiply by the 2nd fork and you end up with 1" static sag and 1.5" rider sag. That's not going to work.

Yes, it's confusing, but it's there, in black and white.

Steve

 

[Steve in sunny Fla]

Why is my free sag the same as my loaded sag?
What is the proper range of free sag above the loaded sag?

HMMM, I smell a trap.

The only way your free sag and loaded sag could be the same is if there's zero shock / fork compression because the preload in the assembly is higher than the weight of the bike and rider.

As far as proper range for free sag? I just got an answer from 2andBlue, that said his penske shock called for 6-12MM. I don't know what the Motool Slacker calls for. The whole Idea, according to Moss, is to not forcefully top out the suspension.

Did I avoid the trap?

 

[connie_rider]

I've been at the computer too long today. Not thinking clearly.
and/or I may have messed up on my posting/math?

1st paragraph;
The 2" of assembly pre-load = 100# of force on the spring.
200 # front bike weight minus that 100# of pre-load leaves 100# that is not supported by the assembly preload.
That unsupported 100# would cause 2" of sag.

Adding a 200# Rider would put 1/2 of that weight (100#) on the front.
That 100# of rider weight would push the front down another 2".
(2" + 2" = 4")
You came up with 3", and you said 200# bike and 100# rider = 3" spring preload.
What am I missing?

I may have found it.
Should be 200# bike (4" spring compression required) and 100# rider (2" spring compression required) minus (the 2" of assembly compression) = 3" 4" of spring compression/Loaded sag..

In your 2nd paragraph you sed;
So we screw the adjuster out 1" to drop the bike 1" and now the rider has the proper 3" rider sag.

I think;
** your first paragraph should say 4" (??)
** and/or you didn't include the 1" adjustment (50#) in your first paragraph. {??}
{Cranking in 1" of adjustment would raise the bike and reduce sag 1"}
** Should be; So we screw the adjuster out in 1" to drop raise the bike 1" and now the rider has the proper 3" rider sag.

Ted

 

[laker9142]

OK, I said I would explain this so here we go. AND since I shot my keyboard off and stated "the math will set you free" I'm going to do it with math.

I understand all that, that's what we finally decided that's how it works. I guess I'm hung up the wording again, could be my problem alone. BUT when the say the spring won't hold the bike up because of a lack of preload. It SOUNDS TO ME that preload holds the bike up. No response required.

Did I avoid the trap?

No trap, the difference in my loaded to free sag is literally .75mm. Which indicates too stiff of a spring. But it's supplied by Traxxion and is 13 years old. I never checked it before but it works well and if anything I could used a stiffer spring at times. I was just curious about what it was supposed to be.

 

[laker9142]

I've been at the computer too long today. Not thinking clerly.

I don't know how people make a living sitting in front of a computer all day. It wears me out quickly.

 

[laker9142]

I dont know but I can tell the difference in sag by adding 30 lbs of camping gear on the pillion.

Yep that would be about 12 mm more sag due to the added load.
I'm glad you chimed in, I didn't know if anyone was interested or not.

 

[Steve in sunny Fla]

I understand all that, that's what we finally decided that's how it works. I guess I'm hung up the wording again, could be my problem alone. BUT when the say the spring won't hold the bike up because of a lack of preload. It SOUNDS TO ME that preload holds the bike up. No response required.

Does this mean you now agree with the quote from Motool regarding spring rate and sag numbers?

 

[Steve in sunny Fla]

Yep that would be about 15 mm more sag due to the added load.
I'm glad you chimed in, I didn't know if anyone was interested or not.

Being on the pillion, it would have a much much smaller effect on sag. That’s almost all on the shock. Racetech lists the shock spring at 750#. Assuming the linkage ratio is 1/1, the linkage mount is about 1/3 of the swingarm length. So it would take 750# to compress the spring 3”, or 1” = 250#. 30# would be .120”, or 3mm. I just did this in my head , so check it before you buy in.

 

[laker9142]

Being on the pillion, it would have a much much smaller effect on sag. That’s almost all on the shock. Racetech lists the shock spring at 750#.

I agree, the math would have been 12mm (edit) (now its 6mm considering there are 2 springs) anyways but I don't even believe that. I only got approximately 1mm by adding 200 lbs. So no way will you get 12 mm from 30 lbs. But the rear is a much stiffer spring so doubt it moves much.

Does this mean you now agree with the quote from Motool regarding spring rate and sag numbers?

I think their statement is very hard to decipher, you basically have to have an understanding of it prior, to know what they're saying. BUT it can be argued that the statement is true.

 

[Steve in sunny Fla]

I agree, the math would have been 12mm anyways but I don't even believe that. I only got approximately 1mm by adding 200 lbs. So no way will you get 12 mm from 30 lbs. But the rear is a much stiffer spring so doubt it moves much.

I think their statement is very hard to decipher, you basically have to have an understanding of it prior, to know what they're saying. BUT it can be argued that the statement is true.

And thinking your way through the “why”rather than blindly accepting is a real challenge. At the limits of my pea-brain.

Regardless, I see your point that the "preload adjuster" would be better understood if labeled a "ride height adjuster". Maybe the Japanese to English translation is poor, like "hard or soft" to describe damping.

 

[Steve in sunny Fla]

I've been at the computer too long today. Not thinking clearly.
and/or I may have messed up on my posting/math?

1st paragraph;
The 2" of assembly pre-load = 100# of force on the spring.
200 # front bike weight minus that 100# of pre-load leaves 100# that is not supported by the assembly preload.
That unsupported 100# would cause 2" of sag.

Adding a 200# Rider would put 1/2 of that weight (100#) on the front.
That 100# of rider weight would push the front down another 2".
(2" + 2" = 4")
You came up with 3", and you said 200# bike and 100# rider = 3" spring preload.
What am I missing?

I may have found it.
Should be 200# bike and 100# rider (minus the 2" of assembly compression) = 3" 4" of spring compression.

In your 2nd paragraph you sed;
So we screw the adjuster out 1" to drop the bike 1" and now the rider has the proper 3" rider sag.

I think;
** your first paragraph should say 4" (??)
** and/or you didn't include the 1" adjustment (50#) in your first paragraph. {??}

Ted

I fixed it , but I wasn’t trying to re-litigate what we’d already proven, just touch on the highlights.

 

[Steve in sunny Fla]

No trap, the difference in my loaded to free sag is literally .75mm. Which indicates too stiff of a spring. But it's supplied by Traxxion and is 13 years old. I never checked it before but it works well and if anything I could used a stiffer spring at times. I was just curious about what it was supposed to be.

I have a notion as to the problem. Let me ask a couple questions.

1) did you assemble the fork? (if the answer is yes, please answer #2)

2) can you describe how you set the 150mm oil height?

This isn't a waste of time.

Steve

 

[kzz1king]

Being on the pillion, it would have a much much smaller effect on sag. That’s almost all on the shock. Racetech lists the shock spring at 750#. Assuming the linkage ratio is 1/1, the linkage mount is about 1/3 of the swingarm length. So it would take 750# to compress the spring 3”, or 1” = 250#. 30# would be .120”, or 3mm. I just did this in my head , so check it before you buy in.

It is a small but measurable amount. One click on the rear to maintain my 34mm. I was talking about the rear sag.

 

[Steve in sunny Fla]

It is a small but measurable amount. One click on the rear to maintain my 34mm. I was talking about the rear sag.

Everything I wrote pertained to rear sag and the rear shock. .120” is just about a short 1/8” more sag on the rear shock. Does that seem about right?

 

[laker9142]

2) can you describe how you set the 150mm oil height?

 

[laker9142]

I think their statement is very hard to decipher, you basically have to have an understanding of it prior, to know what they're saying. BUT it can be argued that the statement is true.

This is how it shoulda been written for clarity and so didn't have think so hard.

After setting rider sag, you'll know if the spring is too soft, because the free sag will be above the recommended measurement. Free sag will be too small of a value. (Whatever the heck that's supposed to be}

I'll be camping for a couple days. it's going to be hot. I think the Dry Creek next week is gonna get even drier.

 

[kzz1king]

Everything I wrote pertained to rear sag and the rear shock. .120” is just about a short 1/8” more sag on the rear shock. Does that seem about right?

Very close. Stock shock revalved but stock spring.

 

[Steve in sunny Fla]

This is how it shoulda been written for clarity and so didn't have think so hard.

After setting rider sag, you'll know if the spring is too soft, because the free sag will be above the recommended measurement. Free sag will be too small of a value. (Whatever the heck that's supposed to be}

I'll be camping for a couple days. it's going to be hot. I think the Dry Creek next week is gonna get even drier.

Responding here because the pdf’s wouldn’t quote. I had the same setup, the free sag and rider sag #s were proper but I ran my compression 1 turn out to slow the brake dive. It was perfect. Based on experience though, if you measured the oil height with the forks extended rather than compressed, you can get the situation you’re describing with static vs rider sag. The air spring becomes to small. I have done a fair amount of this stuff with the c10’s back in the day, and The first time the oil level spec didn’t include “fork compressed”. Have a good trip.

 

[laker9142]

the free sag and rider sag #s were proper but I ran my compression 1 turn out to slow the brake dive.

Brake dive is exactly why I run sag at 35mm. Even at 35 I can't tell any difference in handling, and I've never been passed by any concours or equivalent. With minimal sag I gain 3 or 4mm of usable travel before it bottoms out. That extra travel at the bottom of the stroke is the only place where the "preload" adjustor will have any effect on the spring. The springs (set) gain the ability to support an additional 21 lbs just before bottoming out. (Sag at 35 instead of 39mm)

Also to dispel another mythical commonly held belief, it's not important that both forks be adjusted exactly the same. After all the bolts are tightened up, it's a fork unit, not individual forks. KTM and others have the spring in one side only, damping in the other.

 

[Steve in sunny Fla]

Brake dive is exactly why I run sag at 35mm. Even at 35 I can't tell any difference in handling, and I've never been passed by any concours or equivalent. With minimal sag I gain 3 or 4mm of usable travel before it bottoms out. That extra travel at the bottom of the stroke is the only place where the "preload" adjustor will have any effect on the spring. The springs (set) gain the ability to support an additional 21 lbs just before bottoming out. (Sag at 35 instead of 39mm)

Also to dispel another mythical commonly held belief, it's not important that both forks be adjusted exactly the same. After all the bolts are tightened up, it's a fork unit, not individual forks. KTM and others have the spring in one side only, damping in the other.

You haven’t touched on oil level from my last post, and have you considered its effect on slowing fork compression ?