Xtr m970/GT sts chain rub issues - help

[ishaw]

I've just finished my sts build and its running a full m970 drive train. The issue I have is that I've got the front mech as low as I dare so as not to hit the chain rings, but even like this, when using the granny ring, the chain rubs on the front mech cage at the bottom most point of the cage, rendering the granny gear unusable.

Now I don't use it often (well at all yet as this build has never been ridden, just work stand set up), but I may need to use the granny ring, and its plain bugging me that I can't tune this out. Its a low band/top swing mech and I can't see anything else that I can do to lower the mech.

Has anyone had a similar issue and if so, how did you solve it, as I'm itching to slap on some pedals and take her for a spin.

 

[WD Pro]

Angle of seat tube ? Not something that can be altered though ... :-(

WD

 

[jimplops]

Is that with it in the stand? If so with sag it'll alter the angle when sat on it, also chain isn't too long.

 

[ishaw]

Is that with it in the stand? If so with sag it'll alter the angle when sat on it, also chain isn't too long.

It is certainly possible, will try and see if the 'droop' as the manual call it, makes the difference.

 

[ishaw]

Angle of seat tube ? Not something that can be altered though ... :-(

WD

It can as it goes as its not the seat post its attached to, but a stub bolted on to the frame, so a steeper angle would be possible.

 

[jimplops]

Steeper angle would lift the back end of the mech up, making it worse.

 

[ishaw]

Steeper angle would lift the back end of the mech up, making it worse.

Depends on which side of the bike you stand on, or maybe I meant shallower angle.

 

[66 triumph daytona]

Full M970 on an STS,you have to post pics-please post pics!

 

[ishaw]

Full M970 on an STS,you have to post pics-please post pics!

Some pics here:

http://www.retrobike.co.uk/forum/viewto ... ;e=1998527

Problem solved, two links out of the chain (big to big chain size test indicated it had two links too many. Once I'm sat on the bike, the 'droop' kicks in and everything is rosy.

Just for the record, the front mech mount is not really part of the frame, but a tube bolted to the bottom bracket/stays. It is possible to modify this to achieve a greater angle if one was so tempted, and it would not alter the frame geometry in any way. But as I've no need, I shall leave it be.

 

[jimplops]

Good to hear its all sorted.