Thinwater skinner wrote:
I would remove the shaft/mast from the mirage drive and make sure it rolls true on a flat surface.
I agree that for V-1 Drives, removal of the mast is the best way for straightening. Straightening in place risks cracking the sprocket.
The V-2 is a different matter. Straightening a mast off the Drive risks damaging the mast threads. Since the V-2 sprocket is stronger, it can safely withstand straightening in place.
Mast straightening with stainless sprockets can be done either way, but removal is more accurate. Be sure to replace the cotter pin retainer with a new one if you remove the mast.
Most bends are straight back and can be reversed by re-bending forward. Side bends are trickier but fortunately, rare.
The easiest way to check for bent masts is to measure the spacing between masts at the base or root. It should be within 1/4" of the same measurement at the tip. This would indicate weather both masts are parallel and straight.
Lateral alignment is checked by holding the pedals parallel (make sure they are in the same pin position and pressed forward in the drum). The fins should be aligned and straight up. Minor variations up to about +/- 5 degrees should be ignored. If greater, the problem should be analyzed before any action is taken -- it could be a bent mast, cable adjustment issue or (with stainless sprockets) a chain skip. Each requires a different remedy.