Quote:
Originally Posted by GreyGoose006
truthfully, i cant even read what is on my doorpanel.
secondly, on every car that i have ever looked at at the dealerships, the recomended pressure on the doorpanel is within 2-3 psi of what the tires say.
have you ever noticed that you never see sidewalls that say inflate to 47.5 psi?
they are usually rounded to whole numbers, and about %75 on the time, rounded to either a 5 or a 0.
owners manuals and door panels too...
you never see an owners manual that says inflate the rear tires to 27 psi and the fronts to 31 psi. this would make sense on say a ford ranger, where you know it wont carry much weight, and if it did, it is not much.
in trucks, the majority of the weight is in the cab, on the front axle, yet the tire pressures are usually the same front and rear.
even on high end sports cars, tire pressures are kept at 5 or 0 intervals for the most part, and are the same front and rear.
HMMMM...
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You haven't looked at that many stickers. Dodge, Mitsubishi, Subaru, Kia, Chrysler, Chevy, Ford - MOST of the time have various recommended front/rear PSI, not 25/30/35/40/45. Go by the sticker it is what your car is supposed to ride on. The sidewall is set by the individual tire manufacturer for that specific model of tire. They have to know how much load the tire can handle and at what pressure reliably. If you run at or near maximum load run it at maximum pressure its that simple. Most tires have a max load of 1200-1500lbs per tire. If you figure you have 4 tires on your average car that is anywhere from 4800-6000lbs. Figuring most midsize front wheel drive passenger cars weigh about 3400lbs, you would need another 1400lbs or so to hit the maximum load for most tires. Inflating them to maximum pressure on an average car does decrease rolling resistance but also makes the tire contact patch SMALLER which can cause you to lose control easier.