Originally Posted by
shants
The problem, right now, with the disc bolt on system is that there is really no one manufacturing cogs (is boone still making them), the chainline (not that level's is perfect) situation can be iffy, and there aren't standard flip-flop options. if you're using a front hub, you're going to need to respace, and if you are using a rear, you're most likely dealing with mountain bike hub spacing and will have a freehub body hanging around. the freehub situation is fairly gnarly, because the wheel still has to be dished to the freehub side and the forces generated by the added disc cog are going to be on the under tensioned side of the wheel that isn't built to handle them.
I haven't kept up with who's making them, but it doesn't really matter, the point is that your local machine shop will always be able to make them for you for $beers, whereas the level design would be very hard to reproduce. Respacing a front isn't that daunting in my book, though I wish someone would just produce a purpose-built 120/126/130 hub kthxbye. The rear thing would be a little messy, though you'd also have a built in flip-flop and wider bearing spacing than most SSMTB hubs. Also, I'm not sure I buy that the disc side spoking can't take the torque, it's built to take the stresses from a disc brake, which are serious business even at the rear.