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8mm?

Discussion in 'Bicycle Mechanics and Repairs' started by Tangoup51, 16 Jul 2017.

  1. Tangoup51

    Tangoup51 Active Member

    Just did a service on my rear Avid BB5 Caliper as the damn thing is giving me all kinds of problems.

    After servicing it I realized it only uses 7-9 mm of engaged thread in the rear caliper mount.

    I don't have the original bolt for the lower rear disc mount, but I managed to another and use washers to get it to the right size. I find it weird that the bolt is 30mm long but the mount boss only allows me to use 8mm of the thread for it, before it bottoms out.


    **Edit, does anyone here have Avid BB7s and would you recommend them? (or any calipers under £100)

    Thanks!
     
    Last edited: 16 Jul 2017
  2. Adrian

    Adrian Heed the elf's wisdom

    I am not understanding exactly where the problem lies here. Which thread bottoms out? Can you show us a photo, if that would help?

    I have BB7s on one bike and Spyre TRPs on another. Both are fine, and better than BB5s because they are easier to adjust.
     
  3. ianrauk

    ianrauk Tattooed Beat Messiah Staff Member

    Yes I would recommend BB7's. Easy to fit and easy to adjust.
     
    PK99 likes this.
  4. Threevok

    Threevok Senior Member

    Location:
    South Wales
    I bought a pair BB7's in 2007, as an upgrade for the cheap and nasty i/o ones that came with my Shogun Torsion. They then went on the GT Avalanche when I built it, using the Shogun as a donor bike.

    I refused to switch to hydros for 8 years as the BB7s were so good, and only did so when they finally packed in. I still have the clean-sweep rotors that came with them - on the GT, which is now running Elixir 1's.

    I'd highly recommend BB7's to anyone. The only problems I ever had were my cables freezing in the snow and ice - hardly the fault of the brakes though
     
    Last edited: 18 Jul 2017
  5. ianrauk

    ianrauk Tattooed Beat Messiah Staff Member

    Yep I previously had that problem. It's due to the way the brake cable attaches to the rear brake, in an upward sweep to the caliper so letting in moisture. I tried using grease and vaseline to hopefully seal the outer cable where the inner exits, but no luck. So the only thing to do is cable replacement before each winter. Never had the same problem with the front brake.
     
    Threevok likes this.
  6. Threevok

    Threevok Senior Member

    Location:
    South Wales
    Neither did I with the front one, but the rear was a pain

    Also tried grease and oil on the rear with little effect, although TFT spray seemed to work better, but not perfect

    In the end used cheap BELL cables from bargain shops, and replaced the entire inner and outers before and after winter
     
  7. Tangoup51

    Tangoup51 Active Member

    Thanks for your advice guys!

    Oh and the issue I had was just that the bolts suddenly Stop half way down the thread, I think it was just gunk as I never put much pressure on the bolt to find out if it'd strip it.

    In the end i've ended up with 8-10mm of engaged thread in both the mount holes. Which is less engaged thread than the front, but for probably more obvious reasons.