Hi Martin. Sorry I didn't reply sooner, I have been away on holiday snowboarding.
You turn down the drum to the size of the rotor you have chosen to use. I can't remember the diameter for a 914 rotor, I'll measure my spare pair when I have recovered enough to make it into the loft.
914 rotors are easy to get hold of. Mine came from CSP (www.csp-shop.de).
The caliper mount that Duncan used on his Trekker mounted behind the hub bearing cover plate. At this point it was 4mm steel, and the rest was 6mm steel. If you are making one this way I suggest you add some gussets too.
The position of the caliper mount should place the caliper so that the rotor is central between the pads, and parallel to them. The caliper should also be at the correct angle so that the bleed nipple is at the highest point. |