You're right to be concerned. Many frames from 95 and earlier have seat tubes that bulge out where they meet the bottom bracket shell, and all bikes from that era were designed for conventional-swing mechs, which clamp onto the frame higher than the big ring. Then in the mid 90s, top-swing mechs were introduced, which clamp onto the frame at about the height of the middle ring. These have the advantage of clamping onto the butted section of the tube, so you're less likely to deform the tube if you over-tighten the clamp. But obviously they won't fit if you have a bulged or externally butted seat tube.Bones_dt4":2lm6j6l0 said:apparently there is different types of mech, the most obvious being top or bottom based on the cable routing but i was told that there is a conventional pull and another type.
Something to do with the way the mech ramps the chain over the gear and something to do with the dishing of the rear gears in relation to the front chain rings.
im really unsure what im on about, was just told to make sure i get the correct sort for my bike..