You can run R wheels on the S, no problem.
You can also run radials on the spoked wheels if you seal the nipple holes inside the rim with marine 5200 sealant (good stuff)... you can find pretty detailed instructions in this link http://www.vtxoa.com/forums/viewtopic.php?t=167959 -- it's a long thread... seems like the procedure is somewhere within the first 6 pages of the thread... it is covered more than once in the thread and has pics and the whole enchalada... have fun digging through the thread, but it could be worth your time.
You can also run radials on the spoked wheels if you seal the nipple holes inside the rim with marine 5200 sealant (good stuff)... you can find pretty detailed instructions in this link http://www.vtxoa.com/forums/viewtopic.php?t=167959 -- it's a long thread... seems like the procedure is somewhere within the first 6 pages of the thread... it is covered more than once in the thread and has pics and the whole enchalada... have fun digging through the thread, but it could be worth your time.
