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The inner Zen of tire pressure

N

nickrides

Member
Member
So I've got about 600 miles on my new to me RS2's
I started out with the pressure F/R at 42 cold.
My TPMS, pencil gauge and Slime pump all agree on pressure.
So I started Raising the pressures up and bit and then down and then back up.
I settled on 39 F/R Hot.
I thought I could feel the difference.
Is this all in my head?
Or is it possible to feel subtle pressure changes?
Signed
Smooth ridin'
 
It's not in your head.  IIRC, the guys that did the track day mentioned lowering tire pressures while on the track.
 
I am running a Garmin tire pressure monitors on my rear wheel since my OEM unit died. The Garmin's display is not corrected for temperature as I understand the OEM is. With both tires set at 42 at 65F the front OEM initially reads 43 the rear 42.5 After 5 miles the front reads 44 and the rear reads 48. So if you are setting your tires at 39 hot you are running them way below recommended pressure. 
 
lather said:
The Garmin's display is not corrected for temperature as I understand the OEM is. With both tires set at 42 at 65F the front OEM initially reads 43 the rear 42.5 After 5 miles the front reads 44 and the rear reads 48. So if you are setting your tires at 39 hot you are running them way below recommended pressure.
Click to expand...

Pretty sure the OEM sensor is temperature correct at 68*.

I agree with lather, 39 hot is probably 34 - 35 cold which is way to low.
 
Ok
When I started out at 42 cold they went up to about 44 hot.
Next time I go out there I'll look at the cold pressure and see what it is.
That 39 psi hot sure felt the best thou while riding on various surfaces, new asphalt, old chopped up stuff, tar snakes etc
But I agree, it may be too low for general usage.
Nick
 
Remember the big problem with Ford Explorers and Firestone tires?  Part of the problem I believe was Ford suggesting lower tire pressure to attain a better ride quality.  Feel free to correct my memory if need be.
 
I run 28 front and 30 rear at the track, with sport tires. (On my track bike) Yes they stick better and give better feedback at track speeds. I think that can work to some extent with sport touring tires but they won't last very long.
 
After running Them yesterday at 39 Hot F/R
I checked them today cold
They were 37
I bumped them up to 39 cold
Still lower than than 42 recommended but I think I like them slightly soft, they ride nicer, smoother.
I'm not too worried as those track guys run them much lower and there not killing themselves, too often.
I'll watch the temps and see how it goes.
Heading out Wed for a long loop around W Colorado
Nick
 
My TPMS sensors read 4 PSI over what my hand held pressure gauge indicates, I tested multiple tire gauges and this is a consistent result.

At 42 PSI pressure I get 46-47 on the dash display
 
I agree with GPD. And not just because it rhymes. Anyone else recall back in the day when there were a dozen print motorcycle mags, one of them, Sport Rider or Motorcyclist went to a major race like Laguna Seca and sent staff throughout the parking lot of hundreds of bikes. They randomly went and checked tire pressures on hundred of machines and found over 50% were underinflated, many to the point of dangerous.

I am a tire pressure Nazi, sadly finding many of my family and friends riding out for the season on tires that were fine the 'last time they checked them'....read 14 psi before a hard 300 mile day.  First thing I do when someone rolls a bike in my garage is check tire pressure with my calibrated Michelin Vigil tire gauge. So many are so low, some even not registering on the scale that starts at 10 PSIG.

To me it is the most neglected part of M/C maintenance and performance.
 
I run 42-42 cold. It gives a decent balance of grip and longevity.
The TPMS shows 42psi the same as 3 different digital gauges and one analogue one.
Once the tyres are fully warmed up the TPMS reads 44 front and 45 rear.

However, I run the PR4 non-GT which have softer sidewalls and warm up faster.
If you have GTs you may need to run lower pressure to make the ride softer.

Lower pressure (to a point) will improve grip, but will heavily accelerate wear as well.
It's all about finding a balance that suits you.
I get 10k from a rear PR4 and nearly 14k from a front, but UK/EU roads are not as harsh on tyres as roads in some areas of the USA.

 
I'm repeating myself, but all 3 of my pressure gauges read the same
I'm going to head out on a big loop wed with the tires at 39
It will be a fairly cool day temps 45-60
I'll report back on the pressures I see through out the day, and the conditions.
Nick
 
Nickrides said:
I'll report back on the pressures I see through out the day, and the conditions.
Nick
Click to expand...
With all due respect, IMHO, it's not the pressures (in  the ranges you're talking about) - the tires aren't going to fail catastrophically.  It's how you prefer the 'feel' of your bike - factory specs be left behind. 

I run my tires hard, 2 and 3 lbs above sidewall pressure max, for the way it feels.  So 45 fr, 44 rear - for years.  On my roads I can still take off the chicken strips when I desire with no slip.  Just stating the variation possible, not to start a side arguement.

So pressure it the way you prefer the feel.  After half of the tire life, you might find a less inflated front starts to scallop.  You'll gradually find out about any impact on mileage as the season progresses.  YMMV
 
Redfoxx
I ran my last set of RS3's at 44 F/R -I had a brain fart and thought thats what the book said, whoops!
They felt good. just didn't go real far- 5600 too done.
So with the Lockdown I've had time to play around and yes, ride alot.
Nick
 
Nickrides said:
I'm repeating myself, but all 3 of my pressure gauges read the same
I'm going to head out on a big loop wed with the tires at 39
It will be a fairly cool day temps 45-60
I'll report back on the pressures I see through out the day, and the conditions.
Nick
Click to expand...


You have three gauges that all read the same? Dang, I have around five and none of them read the same.
 
Update
maybe to close out this thread
Put my tires up to 42 42 last night and went out on a 10 hr 540 mile W Colorado E Utah loop.
Was cold when I left a 5:15 am- 21f.  heated jacket was on high!
Ambient temp never got over 68f
Tires were great
The TPMS maxed out pressures at these lower temps showed  44 44
Ride safe in 2020
Nick
 
Tire pressure should always be checked cold. At work we have to wait for a couple of hours before we check tire pressure. If it is a little low we can add but if it is below limits we have to change the tire. If it is too low we have to change the other tire on the same axle. If it is high we leave it alone. Told to never let air out. High pressure will not hurt the tire but low pressure can damage the tire.

This is on Aircraft tires not on motorcycle tires. Many people adjust the pressure to get the ride quality they want. Race tires only have to last for that race. Road tires have a very different job. The tire manufacture gives you the max recommended pressure for the tire and the bike gives you the recommended pressure for the tire. One is based on the construction and safety of the tire and the other is for the safe operation of the bike. Both are based on a cold pressure and take into account that they will heat up and the pressure go up with use.

A couple of years ago I installed new tires and after a few rides I didn't like the way they felt. Just a little vague and would follow parallel defects in the road with a twitch to the rear. Then I found that the 90* valve stem had started to come loose and the pressure was low. I unmounted the tire and re-torqued the stem. Now I love the tires. Made me a believer in pressure checks.
 
JPD said:
Tire pressure should always be checked cold. At work we have to wait for a couple of hours before we check tire pressure. If it is a little low we can add but if it is below limits we have to change the tire. If it is too low we have to change the other tire on the same axle. If it is high we leave it alone. Told to never let air out. High pressure will not hurt the tire but low pressure can damage the tire.

This is on Aircraft tires not on motorcycle tires. Many people adjust the pressure to get the ride quality they want. Race tires only have to last for that race. Road tires have a very different job. The tire manufacture gives you the max recommended pressure for the tire and the bike gives you the recommended pressure for the tire. One is based on the construction and safety of the tire and the other is for the safe operation of the bike. Both are based on a cold pressure and take into account that they will heat up and the pressure go up with use.

A couple of years ago I installed new tires and after a few rides I didn't like the way they felt. Just a little vague and would follow parallel defects in the road with a twitch to the rear. Then I found that the 90* valve stem had started to come loose and the pressure was low. I unmounted the tire and re-torqued the stem. Now I love the tires. Made me a believer in pressure checks.
Click to expand...

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            THIS

:iagree:
 
Bud said:
Remember the big problem with Ford Explorers and Firestone tires?  Part of the problem I believe was Ford suggesting lower tire pressure to attain a better ride quality.  Feel free to correct my memory if need be.
Click to expand...

Hey Bud,
I wasn't for ride quality. At full tire pressure, the explorer failed what Mercedes called "The elk test." It tended to roll over in extreme steering maneuvers. Ford took the cheap fix of lowering the tire pressure. This was one of the events that led to vehicle dynamics control systems becoming standard on SUVs.
 
Why would you check TP Hot? Makes no sense. A hot reading can be affected by air temp and road temp where a cold reading is well, just that, a cold reading.
 
Steiny said:
Dave Moss knows more about tires and suspension settings than 98% of people .

there are so many variables to tires than just 1 magic psi. setting.
Click to expand...

I was fortunate enough to meet Dave last year at a Women's Sportbike Rally that my girlfriend was attending. He setup her FJ09 and my Z1000, which I had just installed a new Bitubo shock and, had fresh oil and springs in the forks. I had set it up pretty close, but Dave made a few slight adjustments to my levers and suspension and it made a world of difference. It was actually shocking. I watch his videos all the time now. Dude knows his stuff.
 
After much experimentation I've settled on 39/39 cold with my Dunlop RS 2's.
Just like they way they feel.
They may not go as far at that pressure, but they don't go very far anyway!
Nick
 
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