Originally Posted by dsaul

Mountain bike frames and 42t chainrings don't go together. The short chainstays and wide tire clearance requirements of modern MTB frames, doesn't leave enough room for chainrings that large. I have built(welded together) a number of MTB frames and its always a challenge fitting the chainstay between the tire and the chainring. On the plus tire (3" tire clearance) frames that I build, a 32t chainring is the max. that will fit.

By the way, quality sliding or rocker dropouts cost me around $150, which is around the same cost as the rest of the frame tubes, head tube and bottom bracket. It would cost me over $300 in raw materials to build that frame and that doesn't include powder coating it or me making any money from it.