Few teeth short of a cog- Mtbr.com
Results 1 to 6 of 6
  1. #1
    mtbr member
    Reputation: happygofun's Avatar
    Join Date
    Jan 2004
    Posts
    149

    Few teeth short of a cog

    Hi, long time lucker first time poster.

    My local shop owner claims I should say this happened "that time I was racing a motorcycle, uphill..."



    But it wasn't that exciting and happened a little downhill from here.



    It started off as the usual headlands loop just across GG bridge.



    Nice ride though mainly fire road. The 34 tooth chain-ring on my cross-check is out of round, but it's been that since I put it on a year ago. There are loose and tight points, significant but it had been trouble free. I think I'd only lost the chain once on this setup. Bouncing down the Old Springs trail into Tennessee Valley the bike ping-ponged off rocks and was a blast.



    It's fun, the speed is limited but you get to look around and spend more time playing on the bike. Then the chain dropped. The wheel locked up and the chain back-wound itself around the 17 fixed cog. Then I heard the alternating grinding and popping sounds of the teeth shearing.

    Come to a stop finally and hop off to survey the damage. Chain really dug into the BB



    The cog was pretty cleanly broken. Hmmm.



    Flip the wheel and limp the rest of the loop home on the 20t freewheel.



    Now just waiting for the replacement cog to come in this week.

    Disclaimer(s)
    1. ss content, well two gears but had to flip the wheel to ride out.
    2. photo's not all from same ride.

  2. #2
    Hit The Road Cyclery
    Reputation: -Anomie-'s Avatar
    Join Date
    Jan 2005
    Posts
    922
    Can't say that I've ever seen that before. Is that an aluminum cog?

  3. #3
    mtbr member
    Reputation: happygofun's Avatar
    Join Date
    Jan 2004
    Posts
    149

    not alluminum

    nor stamped steel. It's a genuine EAI forged track cog.

    Just a bad enough case of chain suck to do it in

    albert

  4. #4
    elbow gloves
    Reputation: kinkcrazy's Avatar
    Join Date
    Nov 2004
    Posts
    221

    brittle fracturing cogs

    there is an article on 63xc.com about the manufacturing process of cogs, describing how certain heat treatments can cause the cogs to become brittle and fracture in violent ways.

  5. #5
    mtbr member
    Reputation: happygofun's Avatar
    Join Date
    Jan 2004
    Posts
    149

    63xc is a good resource for sure

    This cog had a nice long life I guess, many miles and a few chain drops over the course of 6 years. Oh well, new cog will come shortly.

  6. #6
    French for "Suck"
    Reputation: Aeroplane's Avatar
    Join Date
    Sep 2005
    Posts
    140
    Congrats on being one of the few and the proud to have broken an EAI cog. Glad you (and the bike) are okay.

Members who have read this thread: 0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.