Don, I think you mean from 13 to 12 if you are referring to the rear rims on a Comp Coupe, the front original fronts are 11 and they are taken to 10 for some tires. I have driven the toyo WC tires on both width's of rim. The tire looks a little funny on the wide rim and is difficult to mount but it will work. I do not have much to offer on the performance or cornering power difference. I couldn't tell with the short experience offered. By bringing the rim halves narrower we were able to reduce the tire slipping or spinning so to speak, on the rim. A mark on the tire and the rim can provide you with a reference to identify this problem. Don't get your ******* in a bunch over this tho, small issue.
