Tire Pressure

I know the best tire pressure is listed inside the door jam for factory tires and rims. What is the way to calculate best tire pressure for aftermarket rims and ties sizes.

Yes, and it involves the use of the load tables. There are some quirks about how this is done, so it’s best to ask an expert. I happen to be one, so if you have specifics, list them.

And if you have friends who need assistance, then send them here as well.

I agree with Capri that you should get a recommendation on this, but should you choose to go it alone start with the same pressure that’s used in the OEM setup, the pressure on the doorjam, and adjust to taste. Realize that for a given load (which will still be the same) and the same pressure, the same contact area will still exist with the new tires, but it’ll be distributed differently. So a variation of the doorjam pressure may be appropriate.

I’m going to disagree with mountainbike. While it is usual for plus sized tires to use the same load index, there are many situations where part of the equation results in a change from Standard Load to Extra Load - and that requires more pressure to get the same load carrying capacity. This is but one of the quirks I mentioned. So don’t assume the placard pressure applies.