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When I apply rear brakes only (I know this isn't the proper way to stop), it slows me down but never locks the wheel to the point of skidding (on dry pavement anyway). This is a new 'cyclocross' style bike with disc brakes. It has both regular road bike levers and auxiliary brake levers, if that matters. I am exerting quite a bit of force on the lever and they do not touch the handlebars (bottom out). It seems like a defect to me because that's not what I'm used to from my old hybrid bike with V-brakes, but having had it in the shop a couple of times, I'm starting to wonder -- are these brakes ineffective or is this a design feature to prevent skidding?

If this is a flaw, what is wrong - the brakes, the pads, the cables/adjustment or something else?

If it's a feature, how does it work?

  • is the bike brand new, or just new to you? Any possibility that parts could be worn? – PeteH Jan 21 '15 at 20:51
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    @PeteH or conversely not worn in if it's brand new. – Chris H Jan 21 '15 at 21:07
  • Are you using the front brakes at the same time? If you're applying both brakes then the back probably wouldn't lock up. If it still doesn't lock up the wheel with just the back brake then you've probably got a problem. – Mac Jan 21 '15 at 21:26
  • this question is named really badly. Brakes should fully stop the wheels from moving but skidding is not good . – Andrew Welch Jan 22 '15 at 10:18
  • I know skidding is not good, that's why I wondered if the weakness of the brakes might actually be a good thing. The brakes can 'fully stop the wheel' if I spin it in midair. – weblorin Jan 22 '15 at 22:25
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Disc brakes should be capable of locking the rear wheel.

If this is a new bike I would suggest it's a set up/ breaking in issue rather than a fault.

I'm not sure of the brakes you are running, but guessing they're cable discs due to having axillary levers. I'd ensure :

  1. the brake pads are bedded in
  2. the disc brake rotor alignment is good
  3. the pad contact point is correct (refer to your brakes manual)

Check out this question, Disc brake break-in?

If that didn't help I'd check that the auxiliary levers aren't impeding the full cable pull.

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    Disc brakes work opposite of rim brakes in the break in sense. A new properly installed set of rim brakes are as good as they are going to get, and just go downhill from there. New disc brakes aren't nearly as grabby as a set with some miles and pucker stops on them. Depending on the style and setup of brake, the difference can be quite dramatic. – Deleted User Jan 21 '15 at 21:34
  • Thanks for the answer and the link to Disc brake break-in - in fact I have new Avid BB7 just like the poster of that question. I would have thought in my ~50 km of city riding they'd be "bedded in" by now but I'll give that a more thorough try before I take it to my LBS to investigate suggestions 2,3, and 4 (auxiliary levers). – weblorin Jan 22 '15 at 1:17
  • Not quite relevant, but good V-brakes should also be able to lock up the rear wheel. – Batman Jan 22 '15 at 3:25
  • @ChrisinAK I find rim pads like a few km before they reach their peak - but I've been using some quite cheap dual compound pads recently. I've got some better ones on order so we'll see if they behave the same. – Chris H Jan 22 '15 at 18:06
  • I found that my Avid BB7 Sl's took several hundred K's to bed in to the point where I didn't regret having them because they seemed so inferior to hydraulic MTB disks. However, now they have done >3000km and been through one set of pads, they are nice and powerful. Stick with them. – brendan Jan 23 '15 at 0:42
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Just tighten the cable, they just loosen up over time and they don't pull on the brake as well.

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    I don’t know if this is true. Sure, the pads wear down and the levers must be pulled further to reach the same bite point, but the braking force should not be reduced so much. It’s also been “in the shop a couple of times”, wouldn’t they have tried this already? – Swifty Jun 1 at 8:57

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