Hi.. Now I am almost finished to built my Rockman aurem..today I modifieded my back monty rim.. So..how I done it.. First step I cuted out second wall(now my rim is single wal) I made template from steel.. Put it on rim.. Fix with bolts and nuts Then take a drill.. After drilling..it looks like that.. then with file need to make holes better..and..there is the result total save on rim..83 grams Cheers oh yes..visit TRIALPARTS.NET