I had the same questions just a couple weeks ago.....PRC in Houston sent me this......
Hi joe,
Yes, I did them with the tires mounted. Plastidip is not strong enough to withstand a tire mount. I removed the wheel from the truck, cleaned with dish soap, wiped with alcohol. Blue masking tape...get it under the lip, the newspaper to cover the rest of the tire. I did a light coat to start, but then don't be afraid to thicken it up...it needs to be on the thick side to hold up and to be able to peel off if needed. Wait 20 min between coats. I did 4 coats per wheel. Peel tape carefully immediately after final coat.
5 months and no trouble. Avoid hi pressure wash, and wipe lightly, don't scrub. They clean real easy so far.
If you mess up just peel off and try again! Touchups will be a little visible but not too bad.
Good luck an and post pics!
I was worried about powdercoating the wheels cause I've had a few issues in the past with it causing a slow leak at the bead. He thought this was a better option at a fraction of the cost and easily repairable as well.
Joe