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Can't stand the Suspense-shun!

PerusTC

PerusTC

Street Cruiser
Ok,I am hoping Bob,Steve,Rev,or someone can advise me as to a standard or mid-range setting for the suspension front and back to where it doesn't ride like a box car.Or a reasonably inexpensive way to soften it up or make it more compliant without gutting the things.Thx in advance.I know money fixes anything on a bike but,I am in short supply at the present. ;D
 
You might start with 15-20lbs in tghe rea shock. As far as the front forks, you may replace the fork oil with 10 wt.
Thats the cheapest route. Next step would be maybe some progessive springs and rebuild or replace the rear shock.
 
cut 4" off the stock springs from the tightly wound end. Flatten it back down on a grinder. Cut a piece od SC40 pvc the same length as you cut off the spring. use 15 wt at 150mm spring out, fork compressed. then drop in the spring, a 1.25" washer, the pvc spacer, and then the stock washer. Voila, better front end! Steve
 
Not trying to Hi-jack..

Can you also explain the front fork settings...like softer the higher the number, harder the lower?? THANKS1
 
RWJC said:
Not trying to Hi-jack..

Can you also explain the front fork settings...like softer the higher the number, harder the lower?? THANKS1
Click to expand...


Yes. Spring preload on the front forks is increased by turning the spring preload adjuster into the fork. The less lines showing increases spring force (stiffer springs). The more lines showing (adjuster out of the fork) makes the preload softer. Important: you want to have them even. So if starting with so many lines showing, make sure they are equal (the same). Adjust them evenly using the same amount of turns when adjusting.
 
Cap'n Bob said:
RWJC said:
Not trying to Hi-jack..

Can you also explain the front fork settings...like softer the higher the number, harder the lower?? THANKS1
Click to expand...


Yes. Spring preload on the front forks is increased by turning the spring preload adjuster into the fork. The less lines showing increases spring force (stiffer springs). The more lines showing (adjuster out of the fork) makes the preload softer. Important: you want to have them even. So if starting with so many lines showing, make sure they are equal (the same). Adjust them evenly using the same amount of turns when adjusting.
Click to expand...

Pre-load adjusters  cannot make springs softer or harder (stiffer). They are made to adjust the bike up or down. Screw them in and the bike goes up, unscrew and  the bike goes down.  The same goes for preload adjusters on  rear shocks except stock C10's shocks use air pressure in the rear.    They only way to make a spring softer is too change it , or cut it to make it shorter if you prefer stiffer.  If you want to  get the right spring rate you have to know the 'SAG' distance  when you sit on it. Too much sag and the spring is too soft, little to no sag and the spring is too hard for your weight.
Now that you have gotten  the correct springs you can think about getting 'emulators' and  different fluid viscosity so it will soak up the bumps yet not give you that floaty bouncy feeling on the highway and not nose dive during hard braking.
 
So now I have to ask, how is it raising the front forks if it's not  putting more pressure on or compressing the springs (which should make them stiffer by forcing the spring coils closer together) or using an air-shock philosophy? You have my curiosity now.
 
Spring Pre-load and spring rate - CHANGING PRE-LOAD DOES NOT CHANGE SPRING RATE. You don’t get a stiffer spring by adding pre-load. Rather you change the weight point at which the spring starts to move. Once the spring starts to compress it will move at its spring rating.

I do not know how to say it any simpler  than the above and the same rule applies to progressively or a linear wound spring. Pre-load on a motor cycle  just moves the bike up and down and has nothing to do with softer or stiffer.

Maybe this will make better sense:  You clamp the forks (the bike can be on the center stand , side stand or held upright or have some one sit on it)) so they cannot move up and down.  Now when you screw in those pre load adjusters you do compress the spring  (because the forks are clamped and cannot move) and the springs become shorter  because the space inside the forks is getting smaller. Now unclamp the forks so they are free to move. What happens? The springs return to the exact same length as they were before  you screwed in the preload adjusters  and the forks lengthen or raise up  the exact same distance you screwed them in.  The weight  or load (weight of the bike) on the spring has not changed and  hence the spring 'rate' has not changed and the springs are the same length as before.  No change in rate.
Now there is one thing to note,  transferring  a tiny bit of weight forward and back by raising and lowering the front of the bike  will  make the spring expand or shrink a teeny tiny bit but  for this example you would never be able  notice 'softer or stiffer' with such a small weight change. The rate of the spring remains the same.

I hope that makes sense.
http://www.worksperformance.com/html/tpl_desc.html
 
:truce:  PHYSICS...i no gets it... LOL

Yea, it makes sense to me now..i think..I prefer the front lower than the rear by a few notches. So it does help. Thank you all...
 
Howdy,
  I am trying to increase my preload because of pretty severe brake dive on my 99 C10.  I weigh 225 so where should front setting be?  I like the rear on 2ish with 34PSI in the shock.  Also what size socket do I need - My 17mm seemed way too small??  Thanks!!
 
So, I can't fake weight loss on my bathroom scale by standing on one foot? ;D
 
Howdy,
  I am trying to increase my preload because of pretty severe brake dive on my 99 C10. 


  I give up. 
Click to expand...

LMAO


Texastar

The ONLY cure to front brake dive is stronger front springs.  About that 17mm socket, whatcha tring to remove/tighten?
 
Daytona_Mike said:
TexasTar said:
Howdy,
  I am trying to increase my preload because of pretty severe brake dive on my 99 C10. 
Click to expand...

:'(  I give up.  :-[ :-[ :mad:
Click to expand...
Geez Thanks!  I realize I'll need to replace the springs/fork oil and more!  Just thought I would try some more preload first - SORRY MIKE  >:D
 
You don't have to replace the springs to help with your brake dive ... Look at Steve's post about cutting down your stock springs and using a PVC spacer.

Do a search and you might find the whole procedure all spelled out ... it really helps allot ... and cost's very little :)
 
Daytona_Mike said:
Spring Pre-load and spring rate - CHANGING PRE-LOAD DOES NOT CHANGE SPRING RATE. You don’t get a stiffer spring by adding pre-load. Rather you change the weight point at which the spring starts to move. Once the spring starts to compress it will move at its spring rating.

I do not know how to say it any simpler  than the above and the same rule applies to progressively or a linear wound spring. Pre-load on a motor cycle  just moves the bike up and down and has nothing to do with softer or stiffer.

Maybe this will make better sense:  You clamp the forks (the bike can be on the center stand , side stand or held upright or have some one sit on it)) so they cannot move up and down.  Now when you screw in those pre load adjusters you do compress the spring  (because the forks are clamped and cannot move) and the springs become shorter  because the space inside the forks is getting smaller. Now unclamp the forks so they are free to move. What happens? The springs return to the exact same length as they were before  you screwed in the preload adjusters  and the forks lengthen or raise up  the exact same distance you screwed them in.  The weight  or load (weight of the bike) on the spring has not changed and  hence the spring 'rate' has not changed and the springs are the same length as before.  No change in rate.
Now there is one thing to note,  transferring  a tiny bit of weight forward and back by raising and lowering the front of the bike  will  make the spring expand or shrink a teeny tiny bit but  for this example you would never be able  notice 'softer or stiffer' with such a small weight change. The rate of the spring remains the same.

I hope that makes sense.
http://www.worksperformance.com/html/tpl_desc.html
Click to expand...

So if it's for moving the front end up or down, what's the point of it, just to get some more height or less height?  So will this assist me in getting my feet closer to the ground and if so how far can I adjust this (to make it lower?).

 
The point is to keep the suspension from compressing too much when the bike and rider are at rest.  The suspension compression at rest is known as sag, and too much sag can result in excessive bottoming when riding over bumps, which is not optimum and can be dangerous.  The amount of sag also affects how well the bike steers.  The correct amount of sag is generally taken to be approximately 1/3 of the total travel of the suspension.  The preload adjusters can be used to adjust the sag within a fairly small range, and if the sag cannot be adjusted to the correct amount, the next step to get the sag in the correct range is to install stiffer springs.  Here's a short article on adjusting sag:

http://www.triumphnet.com/st/acc/racetech/setup.htm

HTH,
 
I was thinking that too much sag relates to bottoming because in the end your forks only have so much suspension travel. If you eat up a bunch of that travel just by the resting weight of the bike, then you dont have any or that much less suspension travel for bumps. Hence the bottoming. You want to give yourself as much suspension travel as possible for eating up bumps. Yet at the same time you need some suspension travel the other direction too. If your tire goes off something the forks need to expand a little for the tire to maintain contact with the road. Gravity will help a lot in terms of the rest of the bike following along, but you still need some initial expansion room. -- Some where along the lines the guru's at this have determined that aprox 30-35mm of sag is optimal. This gives you some expansion on the one side, while leaving as much as possible for bumps.
 
I have seen this discussed in a different forum with a guy who was pretty good suspension expert. For street use the comment was not to stress out over getting it right on 35mm for example. Its not that critical for 99% of the people. Still you want to be close in that you dont want excessive sag as mentioned, or no sag at all. If your close, probably good enough.

And for those who are getting fancy his comment was that if your springs take more than 10mm of preload in order to get your sag set where you need it, then your springs are too soft and you need stiffer springs.
 
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