Originally Posted by O.J.Sakuma
One thing I always wondered. What about aftermarket wheels/tires?
Let's say I got the V6 Challenger with 17" wheels. I want to go 20" aftermarket. How would I know what psi it should be? Do I ask SRT guys since they got 20" wheels that are OEM?
If they are a different size and tire rating, consult the tire maker or the service center that put them on. If the tires are a direct replacement (size and speed rating), the tire pressure should be the same recommended pressure. But the simple answer is that the pressure you should use should create the same load carrying capacity as the vehicle manufacturer specified. Tires are primarily about carrying the load. The pressure shown on the tire is the MAXIMUM pressure the tire can safely hold. But you don't always need the maximum, and it's not a good idea to always have it filled to the maximum.