by SeditiousCanary » Tue Apr 07, 2009 8:53 am
They are good, but there are a few issues to consider.
Rigid forks: Most do not work well with disc. Ideally, you want forward facing fork dropouts so the brake effort does not try to force the wheel out of the drops. The other option is to have huge lawyer lips, which is what most folks do. Just be aware of it.
Hydra versus Mech: Mostly moot actually. Unless you are doing downhill, heavy cargo loading, or pedicab work, either is fine. The only real reason hydraulic brakes make any sense, is if you need to address heat expansion, brake fade resulting from it, or you already have a set of hydraulic brake laying about. Mechs are nice in the no new tools, any lever works, regular brake cable front, but use compressionless housing. Regular brake housing is too squishy to get good results.
IS versus Post Mountings: Do you want to use an adapter, add extra weight, and unneeded parts? Get IS mounts. Do you want to bolt directly to the frame and fork out of the box? Get post mounts. You can still use an adapter to change rotor sizes on post mounts if you like.
Rotor Size: 180mm. Smaller is fine, bigger is fine. 180mm is what nearly everything is by default, and the easiest to get parts for. It has plenty of stopping power. You will probably need an adapter if you go with anything other than 180mm to position the caliper correctly.
Torx?: Sorry, you are stuck with this one. It is a torque rating concern for the rotor. You have an indexing torque wrench, right?