Number8

We just put on the winter tires and need to inflate them. They're on 19 inch rims. Our regular (all season) tires are on 21 inch rims, both sets are straight from the dealership. The tire pressure posted on the doors say 38 psi for front tires and 50 psi for the rear tires. Does this apply for any tires (i.e. winters, all season, any size rim)? Looking for advice on what or where can I find the right tire pressure info for this? Thank you!

mikey08

While I do not change tire size and keep what I have on I use the gas door values for my settings as per a tech told me at the dealership. Changing rim size etc. based upon weight of car and load can vary in tire pressure. If the dealership supplied those rim sizes I would think the techs would have a suggestion. Person to talk to would be the service manager. You can also search the net for some sites that have suggested tire pressures for tire sizes but they most likely will be the max loads for the tire itself and not for car the tire is placed on. Regards

Mitch Alsup

Proper tire pressure has NOTHING to do with rim/wheel size, proper tire pressure has to do with the size of the contact patch on the road surface and this is absolutely independent of the size of the wheel.

Proper tire pressure will result in a linear gradient of temperature across the tread of the tire, the outside bing cooler, the inside being hotter by about 20ºF. The proper device for measuring this is a "probe tipped pyrometer". You can use this device to setup caster, camber and toe, too. After all is setup, you can then convert it all back into air pressure.