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Mounting V brakes on a Cotic Roadrat

davisdavis Posts: 2,566
edited August 2010 in The workshop
I'm trying to mount an spare set of V-brakes on a Cotic Roadrat.The Roadrat came with those little "stand-off"* things which screw into the brake bosses, and give you a internally-threaded stud on which to mount your brakes.

These stand-offs are slightly bigger than the ones that came off the donor bike, and they prevent the brake from sliding all the way on, and they also stop the peg of the spring adjuster ring from sliding into one of the three holes because it moves the brake too far towards the outside of the bike.

I can't use the ones from the donor bike because the threads in the bosses are different (the larger is just over 9mm and the smaller just over 7mm including threads)


That image looks a little exaggerated: they're really very similar in size, but there's just enough difference to stop the brakes from seating correctly.

So, what are they called?
Do I need new ones?
Where do I get them?


*: I don't know their name, so I'm calling them "stand-offs".
Sometimes parts break. Sometimes you crash. Sometimes it’s your fault.


  • Weejie54Weejie54 Posts: 750
    edited August 2010
    They are called V-brake bosses or studs (or spigots). There are three thread sizes - M8 and M10 coarse and fine.

    Down to measuring the donor bike bosses and locating a pair the same size but with an M10 thread (M10 x 1.25 is most likely the size thread you want - the other 10mm thread, M10 x 1, is the same as a derailleur hanger).

    There are some on eBay: Here. A good engineer should be able to make you some.
  • davisdavis Posts: 2,566
    Thanks -- most helpful.
    Sometimes parts break. Sometimes you crash. Sometimes it’s your fault.
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