Braking question

pabwal
pabwal Posts: 90
edited March 2011 in Workshop
this might be a real thick one but at aloss.

So my brakes are awful especially the back one, from what i can see only the front of the pad is touching the rim. Does this mean new pads or can I adjust them? Plenty of tread left.

Background is that I got the bike, but without wheels so these are the existing pads, since got wheels.

Have adjusted them but no idea how to get them flat on rims, but the back one feels like the cable is stretching, so may need new cables too.

Cheers
Genius Chronometro TT

Comments

  • balthazar
    balthazar Posts: 1,565
    Most brake blocks are fixed with a slight ball-and-socket mounting. Loosen the block mounting bolts a fraction, so they can move stiffly, and pull the brake on with your hand. Position the block squarely and centrally against the rim. Tighten the bolt, taking care not to twist the block as you do so. Spin the wheel slowly, pulling and releasing the brake, and make sure that the block can't touch the tyre at any point.

    It isn't necessary to toe-in the blocks (as may have been done) because the pads will wear into this pattern naturally, whether you like it or not.

    Cables don't stretch. It is more likely that the run of cable housing that skirts the seatpost has been carelessly cut, and is squirming in the cable stops. Pull the ferrules of the end of the cable housing to inspect: it should be neatly cut square.
  • pabwal
    pabwal Posts: 90
    much appreciated, I shall give it a go.

    Cheers
    Genius Chronometro TT
  • Berk Bonebonce
    Berk Bonebonce Posts: 1,245
    Brake blocks on a bike are not meant to be flat against the rim. They are meant to be 'toed in'.
  • Bunneh
    Bunneh Posts: 1,329
    To improve on the 'toed in' reply, he means the front part of the pad is slightly closer to the rim than the rear. This prevents squealing.

    More ino here

    http://www.jimlangley.net/wrench/brake1.htm
  • John.T
    John.T Posts: 3,698
    Toe-in is a waste of time. All it does is make the brake spongy at first, then it wears off anyway. Just set them flat to the rim. If you get squeal it is usually down to rim / block contamination or loose pivots.