Ongoing Crank / Front Mech Problem
A month or so ago I started having problems with changing from the small to big ring on my front crank. As a basic mechanic it played about with the limit screws and tried to fix it but It always wouldn't change up or slipped off the big ring etc.
As my bike was due a biannual service I took it to the LBS who told me the front mech was vent so vent it back and all was working. Having gone out on it last weekend, I changed from small to large and the chain seed to jam and not release from the small cog (I.e stuck to the cogs for more than just half way round) which caused it to momentarily jam in the front mech. From then on I really struggled to get it on the top ring without manual intervention!
Yesterday, my right shifter decided to give up, que trip to a different LBS today. Fitted Force shifters (£250) and told them the front mech probs. the guy said it looked too wide but with some pliers managed to get it working.
On my arrival home took it round the culdesac in my bare feet oat very low speed only for the chain to not release from the small chain ring and jam in the front mech again causing it'll struggle to shift again.
Getting fed up of taking the bike to the shop now and just wanna be out riding. It's a £1k bike with £400 wheels o and SRAM Rival throughout.
What do I do. The LBS has currently has a 20% off sale on but limited availability due to end of season so only have a SRAM Red £250 crank and will have to order a new front mech elsewhere. Tempted to throw cash at the problem as cant be doing with any more hassle but also don't was to spend more than I have to due to not having a superb bike ( although its a better bike than I am rider) and don't wanna look daft with top end crank on a average bike.
What do you suggest?
As my bike was due a biannual service I took it to the LBS who told me the front mech was vent so vent it back and all was working. Having gone out on it last weekend, I changed from small to large and the chain seed to jam and not release from the small cog (I.e stuck to the cogs for more than just half way round) which caused it to momentarily jam in the front mech. From then on I really struggled to get it on the top ring without manual intervention!
Yesterday, my right shifter decided to give up, que trip to a different LBS today. Fitted Force shifters (£250) and told them the front mech probs. the guy said it looked too wide but with some pliers managed to get it working.
On my arrival home took it round the culdesac in my bare feet oat very low speed only for the chain to not release from the small chain ring and jam in the front mech again causing it'll struggle to shift again.
Getting fed up of taking the bike to the shop now and just wanna be out riding. It's a £1k bike with £400 wheels o and SRAM Rival throughout.
What do I do. The LBS has currently has a 20% off sale on but limited availability due to end of season so only have a SRAM Red £250 crank and will have to order a new front mech elsewhere. Tempted to throw cash at the problem as cant be doing with any more hassle but also don't was to spend more than I have to due to not having a superb bike ( although its a better bike than I am rider) and don't wanna look daft with top end crank on a average bike.
What do you suggest?
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Comments
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Is the mech set at the wrong height?
Unlikely but are you're BB bearings sound and free of play?
Personally if the front mech cage got bent on my bike I'd buy a new front mech. It has to be quite a precise width in order to work properly.0 -
The mech hight has been adjusted by both mechanics in both shops. Both have looked at it and said it should be and looks fine.
How do I know if I need a 34.9mm or a 31.8 mm? I'd guess with a modern carbon bike it's the 34.9mm. Assume this it the diameter of the down tube - internal or external diameter.0 -
Measure with a set of vernier calipers if you have access to some.I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.0
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Bullet1 wrote:The mech hight has been adjusted by both mechanics in both shops. Both have looked at it and said it should be and looks fine.
How do I know if I need a 34.9mm or a 31.8 mm? I'd guess with a modern carbon bike it's the 34.9mm. Assume this it the diameter of the down tube - internal or external diameter.
I'd have thought if it's a carbon frame it would have a braze-on mount for the front mech rather than a clamp / band type?0 -
Might be chain suck causing the chain jamming ?0
