The official "my Yaris handles bad on the highway/with crosswinds" thread

[grampi]

Originally Posted by blacksan

If you over inflate without the factor of heavy load then you cause the tire to assume a more rounded, or U shaped profile. This causes less of a contact patch/profile in relationship to tire on the road surface. I am not an artist by any stretch of the imagination so try to imagine the difference between this ) (over inflation) and this ] (correct inflation) in relation ship to contact patch with road surface. Which would you consider more stable?

Not true. As long as you stay under the max pressure listed on the sidewall, you'll suffer no ill-effects (with the exception of a stiffer ride, of course). Tires are made to hold their shape up to the max pressure regardless of vehicle weight. According to every tire expert I've talked to, running with the pressure listed on the driver's door plus 5 PSI is optimum for traction, handling, max tread life, and lowest road noise. The only benefit to running right at the recommended pressure is a smoother ride, but then everything else suffers.