front mech problem
jonrb101
Posts: 86
Hi there,
Putting together a hardtail, mostly from bits I have in the shed / been given / acquired from Ebay. Nearly there but having front mech problems - it's a Shimano LX (FD M571) and when the chain is shifted onto the big ring, the inner part of the cage is touching the teeth on the middle ring, which is strange since both the mech and crank (truvativ 44/34/22) came off the same bike and worked fine! so I'm baffled. The only way I can see of stopping this is to raise the mech, but that will create too much clearance between the cage and the outer ring or getting the angle grinder out!!
Any advice appreciated - is this the wrong mech, maybe designed for bigger gaps between chainring sizes? and if so what mech do I need (9 speed, bottom pull, band on)?
Cheers, Jon
Putting together a hardtail, mostly from bits I have in the shed / been given / acquired from Ebay. Nearly there but having front mech problems - it's a Shimano LX (FD M571) and when the chain is shifted onto the big ring, the inner part of the cage is touching the teeth on the middle ring, which is strange since both the mech and crank (truvativ 44/34/22) came off the same bike and worked fine! so I'm baffled. The only way I can see of stopping this is to raise the mech, but that will create too much clearance between the cage and the outer ring or getting the angle grinder out!!
Any advice appreciated - is this the wrong mech, maybe designed for bigger gaps between chainring sizes? and if so what mech do I need (9 speed, bottom pull, band on)?
Cheers, Jon
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Comments
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is it on parallel witht the chainrings and at the right height to clear the top ring by a mil or 2?
or if i read it another way, you might need to adjust your end screwsyep, my letter 0 key is bust0 -
Hi Drew,
Yes, perfectly parallel and with 2mm gap - just been looking at some tech sheets on shimano website and most front mechs are specified as needing minimum of 12 tooth difference between intermediate and outer chainrings, I have a 10 tooth difference (44/34) and I suspect this is the problem (although I am surprised that 2 teeth make that much difference!).
Is there a mech designed for 10 tooth difference? or should I look to change one of the chainrings perhaps?
Cheers, Jon0 -
sounds like you have some missmatched parts.
what is the frame/cranks etc.."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
The frame is a Carerra Kraken (OK no jokes - it's only a winter hack!) and the chainset is a truvative 44/34/22. The front mech works fine changing up and down, but the middle chainring teeth rub (significantly)on the inner cage plate when in the big ring so I think you're right, there is an incompatibility between chainset and mech - what mech should I be using?
Cheers Jon0