Front mech/chainline problems

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simonrt
Posts: 6
Joined: 2 Oct 2010, 6:56pm

Re: Front mech/chainline problems

Post by simonrt »

cycleruk wrote:Regarding the OP, if there is a spacer on the non-drive side then swap it over to the chainring side and try it.
This will of course move the chainset over a couple of mm' but still keep the same overall width and not compromise the left crank fitting.


There are no spacers on the bb. I think that's why Brucey suggested fitting an mtb bb. the 'shoulders' are each 1mm narrower than on a road bb so should allow for a 2mm spacer on the right side. I talked it thorough with the LBS today and we looked at a road bike with a 34.9 seat tube and 6800 group. with the cable disconnected and the limit screw out the FD is almost touching the frame and there is about 3mm of clear blue sky between the chain and the inner side of the cage in the lowest gear. On mine there is quite a gap between the FD and the frame. My FD is a braze on with the correct adapter [they came together]. The one we were looking at was a band on - I wonder if the band on 6700 FD would sit closer to the frame than braze on + adapter? Opinion seems to be divided on whether my 6700 shifter will work ok with a 6800 FD. Anyway, I've bought a tiny file for £2 and before I spend any more money I'm going to consult Enigma [its an Enigma frame] on Monday and see what they suggest and get them to rule out wonky frame. Happy New Year
simonrt
Posts: 6
Joined: 2 Oct 2010, 6:56pm

Re: Front mech/chainline problems

Post by simonrt »

cycleruk wrote:Regarding the OP, if there is a spacer on the non-drive side then swap it over to the chainring side and try it.
This will of course move the chainset over a couple of mm' but still keep the same overall width and not compromise the left crank fitting.


There are no spacers on the bb. I think that's why Brucey suggested fitting an mtb bb. the 'shoulders' are each 1mm narrower than on a road bb so should allow for a 2mm spacer on the right side. I talked it thorough with the LBS today and we looked at a road bike with a 34.9 seat tube and 6800 group. With the cable disconnected and the limit screw out, the FD is almost touching the frame and there is about 3mm of clear blue sky between the chain and the inner side of the cage in the lowest gear. On mine there is quite a gap between the FD and the frame. My FD is a braze on with the correct adapter [they came together]. The one we were looking at was a band on - I wonder if the band on 6700 FD would sit closer to the frame than braze on + adapter? Opinion seems to be divided on whether my 6700 shifter will work ok with a 6800 FD. Anyway, I've bought a tiny file for £2 and before I spend any more money I'm going to consult Enigma [its an Enigma frame] on Monday and see what they suggest and get them to rule out wonky frame. Happy New Year
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CREPELLO
Posts: 5559
Joined: 29 Nov 2008, 12:55am

Re: Front mech/chainline problems

Post by CREPELLO »

If it's a braze on + adaptor, you should be able to rotate the mech on the adaptor as well as on the set tube. Depending on how low the mech is, you can rotate it on both axis and effectively bring the whole mech closer to the seat tube in the process. You will have to judge whether it's better to rotate the mech forwards or backwards. Forwards could improve shifting, especially if the heal of the mech is further away from the chainrings than the toe is.
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