3

Just that, what's the purpose of the rubber boot on a v-brake? How does it do its job?

4
  • 2
    Keeps dirt and water from entering the cable housing.
    – Rider_X
    Aug 14 '16 at 6:31
  • 1
    In case you're needing one - a new noodle and boot is worth about $2 online. 135 degree ones are for the front, and 90 degree ones are for the rear.
    – Criggie
    Aug 14 '16 at 9:33
  • Thank you both. I'm replacing the rear brake mech at the wheel because one of the arms is broken at the mounting post. I didn't know that about the noodle angles, but apparently I needed to, so thanks again. :)
    – compton
    Aug 14 '16 at 11:12
  • 1
    An unfortunate feature of the V-brake design is that the cable enters the metal "noodle" horizontally. And on some bikes, especially the rear, the cable housing end of the noodle tilts down slightly. Water entering the noodle, and from there the cable housing, leads to rust and resulting cable binding. (Far worse than V brakes are the ones they put on the front of kids stunt bikes -- the style designed to allow the fork to spin in circles. The upward-facing brake-end cable attachment sucks up water and jams in short order.) Aug 14 '16 at 14:35
5

The idea is that it keeps the dirt and water that would otherwise get kicked on to the cable from getting worked into the noodle, contaminating the cable system and causing friction, corrosion, and poor brake feel.

4
  • 2
    A good start ... what would happen if the dirt and water (aka gunk) got into the cable housing?
    – andy256
    Aug 14 '16 at 6:55
  • 1
    "what would happen if" @andy256: it's my understanding that 1) water leads to corrosion of the cable/housing over time 2) gunk and corrosion can lead to friction and binding of the cable within the housing, preventing the cable from moving freely and the brakes from working. 3) if riding in cold weather, water in the housing and/or noodle can freeze, again preventing the cable from moving and the brakes from working.
    – compton
    Aug 14 '16 at 11:29
  • @compton I'm suggesting that the answer be edited to include this information, so that it's more complete. Comments can disappear at any time.
    – andy256
    Aug 14 '16 at 11:51
  • @andy256 Thanks for clarifying, I didn't realize.
    – compton
    Aug 14 '16 at 12:29

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