I had the Avons put on last week. I asked the guy that put them on what tire pressure he recommended. He said 32 front and 40 rear because of the heat here in Sacramento California. I told him the bike states 36 front and 42 rear. He said.."Well..add some air if ya wanna".
Does heat alter tire pressure?? When it's hot do I run less??
I just want to get the best mileage I can from the bike~
Heat most definitely impacts tire pressures and tire life. A tire will heat from contact and friction with the road's surface and from sidewall flex (which is function of tire design, load, speed, and how it is used). Starting from a base of 80F degrees, air volume and tire pressure will increase 10% for every 54F increase in the tire's inner temperatures. Increased tire temperatures will increase traction but decrease tire life. A 10% difference between cold and hot pressures is usually considered to be an optimum compromise between traction and tire life although some sport riders think that a 15-20% temperature increase in the rear tire is necessary to achieve the traction they need (racers may run 25-30% temperature increase but they only need their tires to last the length of the race).
As tires heat up the pressures rise until the sidewalls become rigid enough that they are no longer flexing. This is referred to as equilibrium pressure and will vary depending on the tire, load, and speed. Since there is a limit on how hot a tire can get, there is also a limit on how much the tire's pressure can rise but I think most tires can expand their cold pressure by at least 30 percent. What this means is that it does not make much difference whether you start out at 36 or 42 psi cold, your hot pressure is probably going to be the same, the only difference is that if you start at the low pressure your tire is going to be running a much higher temperature (better traction but shorter tire life).
What pressure is right for your tires and the way you ride? Put 40 psi in each tire, ride for 20-30 minutes to fully heat the tires, and then check the "hot" pressures. If you have 42 in the front and 46 in the rear then the cold pressures probably should be 38 and 42. If you have hot readings of 44 and 46 then the cold pressures should be 40 and 42.
I normally run "hot" pressures of 44 in the front and 46 in the rear. Last weekend I was in Western Montana on a 90 plus temperature day and ran on the freeway at 85-90 mph for about an hour. When I checked my tire pressures afterwards they were 45 and 48 and the rear tire seemed very hot to the touch even though the pressure had only gone up 15 percent. Since the outside (base) air temperature was 90, that indicated the tire temperature was around 170 degrees which I think is pretty close to the temperature limit that you should be running on any tire.
So, if you want long tire life, use high tire pressures and move to Seattle where it is cool and rainy most of the time.
<_< :bigeyes: I run max pressure all the time and I am in the sacramento area gets hot on 105 f days.. let those wheeels role
