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Constant overshifti...
 

[Closed] Constant overshifting past big ring on cyclocross bike - any ideas why?

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[#3452667]

10 spd setup

Compact chainset

Front mech seems to be within a hair's breadth of either undershifting (chain skips on big rig) or simply overshifting past big ring and off into... thin air. ๐Ÿ˜ฏ

It's very difficult to get it to shift into the right place - i.e. the bloody big ring!

That's not normal, is it. ๐Ÿ˜•

I [i]think[/i] I've got everything set up as correctly as possible. Chain doesn't look too worn, big ring is used, but would appear to have plenty of life left in it.

Any ideas?


 
Posted : 12/12/2011 2:12 pm
 ojom
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Mech straight?


 
Posted : 12/12/2011 2:14 pm
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could the mech come down the seat tube a bit?


 
Posted : 12/12/2011 2:14 pm
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It may be what thomthumb says - it was the cause of mine overshifting when I was too stoopid to drop the mech having put an MTB chainset on in place of a road triple. Oops. ๐Ÿ˜ณ


 
Posted : 12/12/2011 2:22 pm
 P20
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Set the outer stop and check it by pulling the cable by hand rather than with the shifter. Then adjust the cable tension on the shifter to suit


 
Posted : 12/12/2011 2:24 pm
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Pie plate it ๐Ÿ™‚


 
Posted : 12/12/2011 2:26 pm
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end stops properly adjusted? you shouldn't be relying on cable pull to determine how far over the mech can move.

Dave


 
Posted : 12/12/2011 2:27 pm
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I might try dropping the mech - see if that helps! It's the same chainset as I've always run on the bike with no problems.. not quite sure what's going on here.

I briefly swapped the BB out for an MTB one (which altered the chainline slightly and so had to adjust cable tension, stops etc.), then replaced with the correct BB. Since then I've been completely unable to get things adjusted correctly.

Will investigate things further, following the above advice. Cheers!

๐Ÿ™‚


 
Posted : 12/12/2011 3:16 pm
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Has the shifter go a trim position? i've see it where the set up on the middle/trim position for the big ring then starts coming off when the cable stretchs.


 
Posted : 12/12/2011 3:44 pm
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I'm having exactly the same problem with my setup. I've tried sorting it again today and it seems to work a bit better (i moved the mech up slightly rather than down!)

SRAM Rival stuff.

Cant figure it out, if I set the outer limit so the chain just clears the mech when its in the 46/12 combo, it wont shift up onto the big ring by a long way.

What am I doing wrong?


 
Posted : 12/12/2011 4:21 pm