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Front Mech just snapped in half...

BhimaBhima Posts: 2,145
edited July 2010 in Workshop
But why? I have used it normally. In the mountains, I do change rings a lot when trying to keep constant power at my preferred cadence though.

Had the bike 18 months and it was the only original component left, except the shifters.

It has split down the middle, if you get me. Luckily I was just a 15 minute descent away from home where I have a spare one.

My question is: is this normal? Is this how they usually "die"? I can't really understand how it happened. I didn't even notice it at the time. I didn't do a "Schleck" and so it didn't immediately impact my riding (I was going to the smaller ring though).

I'd just like to know if this is standard so I can look out for wear in future...

Very difficult to see from the bollox camera pics:


  • Smokin JoeSmokin Joe Posts: 2,706
    You're just unlucky.

    Front mechs generally last for ever and a day.
  • rakerake Posts: 3,204
    what mech is it. campy?
  • BhimaBhima Posts: 2,145
    Nah, this is my Shitmano 'winter' bike. I believe it's the standard Tiagra/Sora mech that comes with the bike (Specialized Allez).

    Just spoke to some chaps who work in the LBS and they've never seen anything like it. They say front mechs generally seize up or bend before getting to the point of snapping.
  • rakerake Posts: 3,204
    ive had seizures but no snapping. looks like it could still shift?
  • ynyswen24ynyswen24 Posts: 703
    I've hadone Campag compact front mech break on me, just above the cage on one of the two parallel arms, it meant that I was on the small ring for the rest of the ride. On the other hand I'm still using a Shimano 600 with the 'arrow' engraving on the winter bike, must be at least 20 years old.
    Just bad luck and very unusual.
  • Ben6899Ben6899 Posts: 8,957
    Which mountains do you ride in? This might hold the answer.

    Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
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  • dgstewartdgstewart Posts: 252
    Same thing happened to me last week on a Shimano 105 front mech. The shifter had been suffering from the common 105 LH shifter problems (jamming, etc) until it recently gave up.

    No sooner had I had the shifter replaced by Shimano than the front mech went. It had split at the front left corner of the cage. I guess it is possible that the shifter problems may have weakened the mech, as it used to downshift with a bit of a clunk, so over time that may have taken its toll.
  • John.TJohn.T Posts: 3,698
    I do change rings a lot when trying to keep constant power at my preferred cadence though.
    I think you have the reason here. You should lift off the power when changing rings. You can get away without at the rear but not the front.
  • freehubfreehub Posts: 4,257
    I've snapped 3 mechs, I've learnt now tho.
  • cougiecougie Posts: 22,512
    Snapped 3 ?? Amazing.

    Never snapped one in >25 years of cycling. I do ease off the power as I shift - I thought we all did that ?
  • BhimaBhima Posts: 2,145
    Yes, of course I ease off slightly when shifting, I just mean I shift a LOT in order to keep my preferred rhythm going.

    Anyway, I thought it was high torque that should be avoided, not high power when shifting. i.e. really really low cadence. It's certainly been the case when i've snapped chains, destroyed cleats and wrote off a crank... (Long story).

  • rakerake Posts: 3,204
    let the tension of when changing man. that says it all, snapped chain and mechs etc.
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