Posted by David on September 20, 1997 at 08:59:05:
In Reply to: Air presure? posted by Janette on September 19, 1997 at 18:23:02:
There is no "correct air pressure for a common tire". Let me explain. There is a maximum pressure for all tires, it is printed on the sidewall of the tire. Basic guide lines are:P-Metric/ standard load tire=35psi, Extra Load designated=41psi.Very High Performance rated=44psi to 51psi. This varies with type of product, construction and manufaturer.
Determining what pressure you should run in the tires on a specific vehicle is different orf separate form the max inflation pressure listed on any tire. You should run what is listed for your particular vehicle. You will find it listed in one of several places. The most common is on the end of the door where the latching mechanism is or on the the door post of the car itself. It may also be found in the glove box or in the owners manual.
This recomended pressure is based on the specific criteria of the vehicle and should be reasonably followed. One important reason is that it is the air within the tire that supports the weight of the vehicle, increased air pressure = greater load carrying capacity visa-versa lower air pressure = less load capacity. Another is that the tire works in concert with the suspension of a vehicle, acting as a pneumatic spring. You will change the "spring rate" by changing pressure.
Some general rules: Higher air pressure = greater load capacity, better fuel economy (because of reduced rolling resistance) , and increased stering response or handling. the down side is a harsher/harder ride and if to high, premature tread wear in the center of the tire. Lower air pressure = softer ride quality, better traction in certain conditions. The down side is less load capacity, lower fuel economy, sloppy handling, and if too low exsessive shoulder wear on the tire.
This all may sound complicated, so the best option is to set your cold tire inflation pressure (meaning check the tires cold, after the tires haven't been driven on and haven't been sitting in the sun) to what you find listed on the vehicle for recomended air pressure and if you ever carry a heavy load for any reason increase the air pressure by a few pounds but not exceeding the max pressure listed on the tire.
Post a Followup