Interesting mechanical over the weekend
Discussion
Never had this happen before.
Climbing, and shifted to the granny ring. Chain makes a bid for freedom and comes off. So far so what....
I could not get it back on. The chain had jammed between the granny ring and the bottom bracket/rear swingarm, and no manner of teasing would get it out.
Push to the top, to various levels of abuse from the others ("first climb and your legs have gone?").
Eventually, 15 stone of mate stands on the handlebars with the bike upside down. I basically lean over the back wheel to fully deflect the suspension and a 3rd chum prises the chain out - just.
Chain is wrecked (several links twisted) and I limp 4 miles with it changing gear every bloody rotation until a nice frenchman with a bikeshop replaces it for me.
All I can imagine is that I shifted as the bike bounced and the rear suspension deflected. This untensioned the chain and it jumped off, and went through a gap that isn't there without major suspension compression and got jammed.
If I was on my own, it was a long push .
Additionally, the bike is probably 10g lighter as that's about how much aluminium it's taken off the frame....
Climbing, and shifted to the granny ring. Chain makes a bid for freedom and comes off. So far so what....
I could not get it back on. The chain had jammed between the granny ring and the bottom bracket/rear swingarm, and no manner of teasing would get it out.
Push to the top, to various levels of abuse from the others ("first climb and your legs have gone?").
Eventually, 15 stone of mate stands on the handlebars with the bike upside down. I basically lean over the back wheel to fully deflect the suspension and a 3rd chum prises the chain out - just.
Chain is wrecked (several links twisted) and I limp 4 miles with it changing gear every bloody rotation until a nice frenchman with a bikeshop replaces it for me.
All I can imagine is that I shifted as the bike bounced and the rear suspension deflected. This untensioned the chain and it jumped off, and went through a gap that isn't there without major suspension compression and got jammed.
If I was on my own, it was a long push .
Additionally, the bike is probably 10g lighter as that's about how much aluminium it's taken off the frame....
Having difficulty picturing it, but could you put one of those lizard skin things on the swing-arm to make the gap smaller to reduce the liklihood of it happening again? Is the chain tension ok? I had this happen a few times on my old Kona and the spring in the rear mech had lost sufficient strenth so when shifting to the granny ring, the tension in the chain didnt pick up quickly enough and the chain dropped. It does sound like bad luck either way.
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