Tire pressures in hot weather

[vito1943]

I've found that I like the way the RT rides with tire pressures slightly higher than what Can Am recommends. I was keeping 20 in front, 30 in rear. But yesterday which was quite warm, near the end of a 3 hour ride, my TPMS app (FOBO2 Bike) warned me that the rear tire pressure was at 36, which I had previously set as the upper warning level. I was a bit surprised that riding raised the pressure that much, so today I let a bit of air out and lowered the pressures to 19 in front, 29 in rear. This all made me wonder what the upper limit for the stock tires would be.

[Piratezz]

Air gets more dense, when hot. on a warm day it is perfectly normal, that tire pressure goes up, dunno what the max pressure would be, but I am sure, Blueknight will chime in, else Peter.. they are the tyreguru's on this forum.
but an increase of 6 is nothing to worrie about

[2dogs]

As you've noticed tire pressures can vary greatly given different ambient conditions. If you've read any of the many threads on this site you'll find that opinions come from many directions and for many reasons. And yes the tyreguru's have narrowed down the parameters based on safety and longevity. It's about an even split between those who prefer one pressure over another pressure. Use your FOBO's to adjust your particular pressures to your riding style and likes and stick with them. 36 PSI in the rear OEM tire will rapidly wear down the center of your tire. Ride happy.

[Mikey]

For one thing if I was you, having the fobo is a great idea, check the pressure before a ride and make sure you're in your happy zone, but you have to remember that air temp is going to change things a little , and riding it will do the same!! You will drive yourself nuts if you watch it like a hawk, use it as a guide, ride more, worry less, smell the roses!!!

[BLUEKNIGHT911]

As you've noticed tire pressures can vary greatly given different ambient conditions. If you've read any of the many threads on this site you'll find that opinions come from many directions and for many reasons. And yes the tyreguru's have narrowed down the parameters based on safety and longevity. It's about an even split between those who prefer one pressure over another pressure. Use your FOBO's to adjust your particular pressures to your riding style and likes and stick with them. 36 PSI in the rear OEM tire will rapidly wear down the center of your tire. Ride happy.

For clarification I differ on the PSI 's affecting the wear for KENDA tires in that ..... 90% of tire wear for Kenda Spyder tires has to do with the construction of the tire. Folks here have used various PSI's plus or minus as much as 6 , and the results for tire wear remain pretty consistent no matter what the PSI is ..... The WEAK construction allows the Tire to Balloon at speeds over about 35 mph, and this is the main cause for wear ...... This occurs predominantly for the REAR tire because it's a lot wider than the fronts. .... I have always said " excessive wear for the fronts " is almost always an Alignment issue. Wear when using Kenda tires ( on the fronts only ) is usually pretty decent, but Auto tires will last longer , even the softer compound Auto tires ...... JMHO ...... Mike ..... I'll let Peter chime in of the PSI / Temperature thing ....

[2dogs]

My point was that no matter what PSI you run in the Crapenda it's going to prematurely wear down the center tread of that tire. I think it's just about a dead horse now but BRP continues to mount them on their machines. My sinking feeling is, and truly hope not, that some unaware spyder owner is going to suffer a blowout and crash their spyder because they never thought their rear tire would wear down so quickly. Most cars get 50/60k on tires these days and who (unknowingly) wouldn't think a spyder couldn't get the same?

[Lew L]

Air gets more dense, when hot. on a warm day it is perfectly normal, that tire pressure goes up, dunno what the max pressure would be, but I am sure, Blueknight will chime in, else Peter.. they are the tyreguru's on this forum.
but an increase of 6 is nothing to worrie about

"Air gets more dense, when hot." I'm not too sure about that -------- In an enclosed vessel the pressure will certainly go up. Air molecules move faster at higher temps, attempting to push further apart( lower density) but higher pressure.

I could be wrong of course, ask your local chemist about Boyle's gas laws.

Lew L

[Lew L]

.

Vito,
Pressures like those 30PSI and above on a Crapenda tire will soon have you changing to a proper Auto tire with much lower pressure ( 20psi or so) and much longer tire wear.

Lew L

[UtahPete]

To respond to your title question; YES! Temperature can affect tire pressure. The TPMS in my truck always shows at least a 3 psi difference between the side in the shade vs in the sun. Once I start driving down the road and the tires heat up from friction, pressure differential goes away.

Bottom line is for stock tires on any vehicle ALWAYS go with the manufacturers' recommendations, or pay the price, one way or another. Tire pressures should always be set to specs when COLD, never directly after a trip when they're going to have elevated temperature and therefore pressure.

[UtahPete]

As you've noticed tire pressures can vary greatly given different ambient conditions. If you've read any of the many threads on this site you'll find that opinions come from many directions and for many reasons. And yes the tyreguru's have narrowed down the parameters based on safety and longevity. It's about an even split between those who prefer one pressure over another pressure. Use your FOBO's to adjust your particular pressures to your riding style and likes and stick with them. 36 PSI in the rear OEM tire will rapidly wear down the center of your tire. Ride happy.

[Peacekeeper6]

"Air gets more dense, when hot." I'm not too sure about that -------- In an enclosed vessel the pressure will certainly go up. Air molecules move faster at higher temps, attempting to push further apart( lower density) but higher pressure.

I could be wrong of course, ask your local chemist about Boyle's gas laws.

Lew L

I have to agree with you, Lew. Cars and bikes tend to run a bit quicker when it's colder because the air is MORE dense.

And a baseball that is hit when it's in the 90s will travel just a bit further than when it's hit in the 40s. Why ??

Because it is less dense.

[Isopedella]

This is what Peter advised me when I asked the pressure question. Hope it helps.
The majic number it seems is 4 psi gain after its all warmed up from cold
Here is Peters short version.

"16 - 18 psi up front to start with, but please bear in mind that with radial tires, harder/more direct steering DOES NOT necessarily mean you are getting better traction &/or control, so to erroneously chase that firmer/more direct 'feel' to the detriment of handling, ride, and wear et al from your tires is really not such a great idea!

Many people have become used to that 'firmer ride' thing thru driving on over-inflated &/or lower profile tires, but the reality is that radial tires in particular NEED to flex somewhat in order to keep the contact patch firmly on the ground and work their best for you, altho going too low is also a risk! So start with your cold start tire pressures at 18 psi & look for a 4psi increase after an hour's riding - LESS than a 4psi increase means your cold start pressure was too HIGH, drop a psi out before your next ride; while MORE than a 4psi increase means your cold start pressure was too LOW, so add a psi before your next ride. Altho the vast majority of Spyders & the tires they can wear will easily fall within that 16-18 psi range, spending a little bit of time now in getting close to the ideal pressure for YOU & YOUR riding, load, surfaces, etc will pay you back in better ride, handling, traction, puncture resistance, tire life et al throughout the tire's life..... "

[BLUEKNIGHT911]

My point was that no matter what PSI you run in the Crapenda it's going to prematurely wear down the center tread of that tire. I think it's just about a dead horse now but BRP continues to mount them on their machines. My sinking feeling is, and truly hope not, that some unaware spyder owner is going to suffer a blowout and crash their spyder because they never thought their rear tire would wear down so quickly. Most cars get 50/60k on tires these days and who (unknowingly) wouldn't think a spyder couldn't get the same?

2dogs I got your point .... and about the PSI's ..... I only wanted to point to..... WHY THEY WEAR so quickly .... it's all about the construction....I've seen video's a small bridges made of CARDBOARD that allowed a car to drive over it ..... also similar bridges made of wood that couldn't ... It's all in the actual construction ...... JMHO .... Mike

[BLUEKNIGHT911]

To respond to your title question; YES! Temperature can affect tire pressure. The TPMS in my truck always shows at least a 3 psi difference between the side in the shade vs in the sun. Once I start driving down the road and the tires heat up from friction, pressure differential goes away.

Bottom line is for stock tires on any vehicle ALWAYS go with the manufacturers' recommendations, or pay the price, one way or another. Tire pressures should always be set to specs when COLD, never directly after a trip when they're going to have elevated pressure.

Just to add some clarification ....Peter and I always State COLD Tire pressures, we have already added in the normal Temp change that usually occur from riding ..... Mike

[2dogs]

LOL, I think we're all on the same page, but not all at the same time.

[SkipH]

Don't forget that the catalytic converter and muffler is in front of that rear wheel.

[BLUEKNIGHT911]

Don't forget that the catalytic converter and muffler is in front of that rear wheel.

If this makes a difference ..... I don't think they or you have instruments that can measure that small of a Temp difference ..... JMHO ... Mike

[RazzleH]

For clarification I differ on the PSI 's affecting the wear for KENDA tires in that ..... 90% of tire wear for Kenda Spyder tires has to do with the construction of the tire. Folks here have used various PSI's plus or minus as much as 6 , and the results for tire wear remain pretty consistent no matter what the PSI is ..... The WEAK construction allows the Tire to Balloon at speeds over about 35 mph, and this is the main cause for wear ...... This occurs predominantly for the REAR tire because it's a lot wider than the fronts. .... I have always said " excessive wear for the fronts " is almost always an Alignment issue. Wear when using Kenda tires ( on the fronts only ) is usually pretty decent, but Auto tires will last longer , even the softer compound Auto tires ...... JMHO ...... Mike ..... I'll let Peter chime in of the PSI / Temperature thing ....

My basic Kends perform a little differently to your advice, Blueknight. Fronts at 17 PSI cold give me 30+K km. Rear at 22 PSI cold gives me 20+K km. Not arguing with you, just stating my facts with about 70K+ experience, the last 50K km mostly in the hills, with vigour. Present ryde is 2020 F3Ltd.

[Little Blue]

....I have been doing the 4 mile check for a long time. I have been doing this for years. .....

[BLUEKNIGHT911]

My basic Kends perform a little differently to your advice, Blueknight. Fronts at 17 PSI cold give me 30+K km. Rear at 22 PSI cold gives me 20+K km. Not arguing with you, just stating my facts with about 70K+ experience, the last 50K km mostly in the hills, with vigour. Present ryde is 2020 F3Ltd.

Thank you for commenting .... Anything I say about Kenda tires is gleaned from what others here have said ( except for their construction ) since 2009, I have always switched to Auto tires ASAP .... Kenda has changed their tire compound formula a few times during that period .... I have read that a few folks ( very few ) have gotten mileages as high ( and more ) than auto tires. .... These folks seem to be in area's where the road surfaces are unique ... in that tires wear LESS quickly than most roads .... Although I know a lot about tires, I have NO answer as to why this is possible ..... over to you Peter ......Mike ..

[rv6a]

You are correct, air gets less dense with temperature and altitude.

"Air gets more dense, when hot." I'm not too sure about that -------- In an enclosed vessel the pressure will certainly go up. Air molecules move faster at higher temps, attempting to push further apart( lower density) but higher pressure.

I could be wrong of course, ask your local chemist about Boyle's gas laws.

Lew L