Just got a set of Michelin tires put on my Pontiac Grand Prix, 2001.
Checking the recommended tire pressure on the label on the truck lid
revealed that I need to inflate the tires to 30 PSI. This seems low to me,
does anyone know why the recommended inflation is 30 instead of 35, which
is where my other GM vehicles are set. The tire size is 225-60-16, my
other cars have 15'' tires. Would this be the reason for the lower
Recommended pressure is a compromise between ride and mileage. If you
like a comfortable ride and acceptable handling go with the tire
pressure label. If you are carrying a heavy load, want a little better
gas mileage, or a little better handling go with the maximum pressure as
indicated on the tire.
Or just split the difference and go with 32/33 psi
It is done so that the ride is more comfortable. If you don't care
much for a softer ride and want a longer lasting tire, up it to 35
psi. The tires will wear more even. Did the old tires wear out on the
side more than in the middle ? Upping the psi to 35 will make them
wear even. Only downside is that the ride is a little harsher, but
really not much. Try it.
It may not affect tire wear at all. The 30 PSI level may be all that is
needed to give the correct contact patch for the weight of the vehicle.
More air may just cause increased wear if it creates an overinflated
Want to see if the contact patch on a tire is correct and check for
alignment problems easily? Take a piece of chalk and rub it across the
tire treads in 4 places. Now drive across a level parking lot and look
at the chalk marks on the tires. if they are worn evenly across all the
tires your doing good. If they are worn off on the outsides of the tires
and not as much in the middle your underinflated, if they are worn off
in the center and not the outside of the tire your overinflated. Worn on
either side of the tires shows tow or camber problems (unless it's a
swing axle vehicle like a Ford or older VW)
Well, that's why I asked how the tires were wearing. Trial and error.
Every car I have owned and was told to put 30psi in by the
manufacturer would wear on the sides more then the insides. Pressures
were checked at least once a month. After switching to 35 psi I have
gotten even wear on several cars.
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