Front Mech not indexing correctly on to large ring.
beardytwo
Posts: 174
Wonder if any one out there can answer this? I have been building up a Dirty Jo which is essentially done but the front mech is causing me grief. Its a brand new deore dual pull but is configured as a top pull. Frame is 31.8 so have used the spacers provided by Shimano so the grip is the right size. Frame is fitted with an Octalink BB (113mm I think!) and Shimano Cranks. when I shift from small ring to middle all is ok and smooth. When I go from middle to large the inner face of the mech chain guide clashes with the inner surface of the large ring before it has clicked and indexed. It appears that the chain ring is not far enough away from the frame to allow the mech to click and hold on the large ring. To this end I have removed half of the frame spacer on the mech so that the mech moves slightly away from the cranks. This worked but I'm not confident that the mech is gripping the seat post well enough. Is it that the BB is not long enough? (118 instead of 113mm) or am I completely out of wack and its something else. Frame seams good so I don't think its just poor tolerences. Sorry for the ramble and hope this makes sense. Any advice would be great as this is the final thing to sort out.. :x Cheers as always...
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Comments
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Sounds like a set up problem ie the H stop and cable tension.
Ensure it is at the right height.
Always use the correct band spacers for the mech.0 -
I think I'll start from scratch, Follow the Parktools instructions to the letter and as you say use the band spacers.( I'm only using one at the moment not both and overnight the mech is moving! If I still can't solve it it might be a trip to an LBS. Grips in Rayleigh is my local and are quite good. Don't like giving up though.. :evil: Thanks sonic..0
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Did try that one but I would need to move it up significantly to solve then this causes other problems. Reading (again) the parktools explaination I may not have adjusted the H and L screws so that the mech cage is very close to the chain without touching. Going to try again tonight.0
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Well solved it. Started from scratch, reset height, used both correct sized band spacers for the frame, adjusted limit screws and still no joy. wouldn't index onto large ring :evil: . Adjusted indexing by tweaking cable tension still wouldn't. Then notice a kink in the cable where its clamped at the mech. Changed cable, setup and voila! :P I guess the cable was flexing instead of pulling because of the kink. Thanks for all the help to keep me going...0
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Ah, bad luck! Happened to me that one!0
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Ah, bad luck! Happened to me that one!0