Jumpy Gears

chrismurdoch
Posts: 7
Hi
I've got a pretty new bike with a triple. The chain has started to jump backwards and forwards between cogs when on the biggest 3 cogs on the cassette - just won't settle.
I'm not a total newby but have no idea what I should be adjusting to sort this one out! Hanger isn't bent. Whole bike is less than 2 months old.
Any help much appreciated. Would take back to the shop but just don't have the time to get there apart fromn Sundays when they close.
Ta
I've got a pretty new bike with a triple. The chain has started to jump backwards and forwards between cogs when on the biggest 3 cogs on the cassette - just won't settle.
I'm not a total newby but have no idea what I should be adjusting to sort this one out! Hanger isn't bent. Whole bike is less than 2 months old.
Any help much appreciated. Would take back to the shop but just don't have the time to get there apart fromn Sundays when they close.
Ta
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Comments
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The rear mech isn't adjusted properly. There is an adjustment screw at the end of the gear cable, as it feeds into the rear mech, and lots of books and internet guides out there to show you what to do with it.0
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Also check the rear derailleur gear, the jockey wheels could be loose or worn, check all the bolts, if they are all OK then take your bike to your local shop and get them to check the alignment of the frame and the rear derailleur hanger and the derailleur its self as it may have been damaged at sometime, which would affect the running of the chain on the cassette.
Bike Builders Hamilton0 -
When posters mention "New bike" and "gears jumping" that means usually one thing, cable stretch.
Gear cables (no matter how expensive a bike) start to stretch from new and give a slackess in the gears. This is why you usually have 4 to 6 week free service from your LBS.
It'll take a LBS about 5 minutes to adjust both front and back.CAAD9
Kona Jake the Snake
Merlin Malt 40 -
Thanks all!
Should I be particularly concerned that it seems to index fine on smaller cogs but not on the bigger ones.?
Adjusted the indexing before my Sunday ride and it was better but not right.
I had assumed cable stretch but am worried that it may have been dinked and the hanger bent. Seems OK visually but I assume that it wouldn't have to be out by much to cause problems?0 -
When posters mention "New bike" and "gears jumping" that means usually one thing, cable stretch.
Gear indexing doesn't just go wrong for no reason. If you've had a fall and have some reason to suspect physical damage then maybe your analysis holds water. If not, then on a new bike, cable stretch is by far the most likely cause.I had assumed cable stretch but am worried that it may have been dinked and the hanger bent.0 -
Thanks, no reason to suspect damage. Just assumed that the shifter changes the cable length by a set amount each gear change so am puzzled as to why the problem is only evident on the big cogs. Could be the cumulative effect of a small error.0
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What derailleur and cassette? Surprisingly, the spacing between cogs on (some) Campag cassettes is not equal - different by tenths of a mm here and there, so it can be fine on some shifts and not others if the spaces are out of order. If you do get the spacers all out of sequence, you or your shop need to spend some quality time with a micrometer getting the right ones in the right spot. Grrrrrrrrr!!!!
Dunno about Shimano or SRAM though.
Cable stretch still the likely culprit though, or even slippage in the clamp bolt on the mech.Open One+ BMC TE29 Seven 622SL On One Scandal Cervelo RS0 -
chrismurdoch wrote:Whole bike is less than 2 months old.
In which case... take it back to the shop and get them to do it.I'm at that difficult age... somewhere between birth and death.0 -
Phone up the shop and see if they'll do it after hours seeing as you cannot get the bike to them during hours, or drop it off as you go past and post them the key.0
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Cheers all.0
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I had a very similar problem. Turned out to be a kink in the cable, which was less than 6 months old. This was Campag. Changed cable after many hours of adjusting/ checking, making improvements but still not right. I even stripped, cleaned and rebuilt the lever before finally fitting a new cable. The rear change is now sublime.
Worth a check if everything else appears ok and stretch/ adjustment is correct.0