I have some ssr mesh that has been reversed on the way to me. When i take delivery i will be checking out how they have been done so that i can hopefully advise everyone else with the secrets lol!
Just looking at it from a logical standpoint (i have never actually seen how the inners are welded to the outers) one would think that it is possible to unbolt and grind/lathe off the welds, flips the inners, use a high tensile bolt and then stitch weld the inner back to the outer. While this may not be "legally safe", as with all of our modifications i think that if you exercise a bit of common sense and sense of personal preservation it is possible.
Having said that... rims from japan are readily available. And you can also get decent widths, not 6.5 junk. There are several site sponsors on this site, including myself, that are able and willing to import rims for a customer.
Edit- I do not recommend using this technique, nor do i support unsafe modifications on the road or the track.
Hope this helps,
Justin
