what tire pressure should i have?

shane93nc said:

i switched from the 17x8 bullit rims to the 17x9 cobra r's and i kept my 245/45/17 goodyears.The factory says to have 30psi in the tires for the factory wheels,but when i had my cobra r's put on,the tire place only put 25psi in them.Is this right?Or should i continue to go with what the factory recommends even though i changed rim size?Thanks Shane

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Tire pressure remains the same no matter the rim size. Run it at the specified rating, or a bit lower depending on your preference.

run 30 for daily driving....

run like 20 in the back if u r racing and keep the front inflated to max

For daily driving I run 30 psi in the rears and 34-37 in the front.

From another thread I posted in:

Forget the 44 psi max. Those numbers indicate that it's a higher quality tire, and you'd only run close to that when road-racing. The goal with tire pressures is to have the same loaded radius on the front and back wheels. That means from the hub to the ground. Since the front of the car weighs more than the rear, that's why you want more pressure in the front than the rear.

I run from 35-36 in the front and 32 in the rear. Yes, I sacrifice a bit of turn-in sharpness by not running higher, but the ride suffers too much if I go any more. I run 32 in the rear to match the radius in the front.

Basically, just start at LEAST with what Ford recommends and add more and more pressure (but not beyond max) until the ride suffers too much. Higher pressure is generally better for the tire anyway since it runs cooler - heat cycling wears out a tire and also makes it harder - less traction.

shane93nc said:

i switched from the 17x8 bullit rims to the 17x9 cobra r's and i kept my 245/45/17 goodyears.The factory says to have 30psi in the tires for the factory wheels,but when i had my cobra r's put on,the tire place only put 25psi in them.Is this right?Or should i continue to go with what the factory recommends even though i changed rim size?Thanks Shane

Click to expand...

I run 35psi at all 4 corners. For me the best of both worlds: handling and ride
comfort. Of course, during winter you have to check it more frequently with
the cold air dropping it. Mark

I run 32 psi all around