Front mech problem when on new frame
GT-Chris
Posts: 5
Hi there,
I've just bought a new GT avalanche frame and my front mech doesn't seem compatible, although it worked fine on my last GT.
It's a Shimano XTR top swing style mech, and even though the lower limit screw is wound out the mech won't move in far enough to A. Stop rubbing against the chain and B. to change down to the bottom ring from the middle.
Also, the mech cage is so close to the rear tyre when in the bottom ring there wouldn't be any room anyway.
I hope all this makes sense and i'm wondering whether a conventional style mech might be a better option? It's a top-pull cable too.
Cheers
Chris
I've just bought a new GT avalanche frame and my front mech doesn't seem compatible, although it worked fine on my last GT.
It's a Shimano XTR top swing style mech, and even though the lower limit screw is wound out the mech won't move in far enough to A. Stop rubbing against the chain and B. to change down to the bottom ring from the middle.
Also, the mech cage is so close to the rear tyre when in the bottom ring there wouldn't be any room anyway.
I hope all this makes sense and i'm wondering whether a conventional style mech might be a better option? It's a top-pull cable too.
Cheers
Chris
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Comments
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Sounds like the BB axle is too short (ie wrong chainline for this frame)0
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Well you're right i think, a longer axle will sort the problem but the chainline is way out already so will that make things worse with regards to shifting properly? I can't see a way of adjusting the rear chain line to make up for it.0
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What measurement do you get for front chainline (measure from middle of seatube to middle of middle ring). And what chainset and BB?
Could be a design of the front mech, maybe it was for 50mm chainlines only - some Deore ones used to be like this.0 -
The front chainline is 48mm. My chainset is a fairly old SR Suntour set, and the bottom bracket is a 68x110. I'm intending on changing the chainset and bottom bracket in the near future, so this is a temporary fix. Hopefully a BB with a longer axle will sort it for now? Maybe with a 113mm axle?0
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Worth a try, it will move it away a fraction.0
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Yeah i think it's my only option for now. I've had a look at the mech details and it supposed to have a 50mm chainline, so i'll see what happens.
Cheers0