Originally Posted by
Ron Damon
If it only were? It is.
.These rigs can be built as 406|451 disc or 451 rim.
Are you sure that the 20" frame can't use 406 with rim-brakes? I'm not sure what kind of brake is being used on the frame in that photo, but, it appears that the brakeshoe is moved up to the extreme end of the brake to match the 451 rim. The fork definitely has a V-brake setup that way. Most 451 bicycles I've seen are using C-caliper brakes, which attach to a hole centered on the frame/fork.