# Ghost shifting



## ErickKTM (Jul 29, 2004)

What causes ghost shifting and how to fix.

Both my bikes will shft to a harder gear at the worst times.:madman: I have a brand new Santa Cruz superlight that will ghost shift just riding wheelies down the road. 

The bike shift gear to gear just fine.

Thanks


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## bloodyknee (Jul 29, 2008)

Are you riding near a haunted house?


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## IRONMAN1518 (Jul 19, 2008)

Too many things can cause it. Some are dirt in the cables, dirt in shifters, cables have stretched and just need adjustment, cables are frayed inside the cable housing, bent rear der hanger, bent der, etc etc. Hold are the cables, what kind of shifts/derailleurs? Only the back or both ghost shift?
Give more info and maybe can help you.


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## Fungazi (Mar 31, 2005)

True "ghost shifting" is when the bike shifts perfectly in the repair stand (thus eliminating bent der hangs, stretched cables, etc etc) but shifts on its own while under riding loads.

Two major causes of this are frame flex / pivot play and (on full sus bikes) cables routed in such a way that suspension movement causes cable motion (additional tension, usually). 

Since you describe your bike shifting into a harder gear (I assume on the rear), that means your cable is somehow loosing tension (unless you have Shimano rapid rise shifting). That's pretty rare in "ghost shift" situations, so maybe you do have hesitant shifting (sticky cables / gummy shifters) or a bent der hang. If you DO have rapid rise shifting, check that torquing your frame / suspension isn't putting any tension into the cable. For that matter, I suppose some arangements might cause loss of tnesion, if the frame actually twisted, say due to very worn pivots (or being a thin tubed frame).


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## chomxxo (Oct 15, 2008)

It's possible that the suspension has something to do with ghost shifting but much less likely than other drivetrain issues. 

I suffered a bad problem with ghost shifting and eventually replaced everything. As Fungazi mentioned it was one of those that shifted on the stand fine. The varied stresses of pedaling can cause differences in shifting performance that might make you think it's suspension flex. 

I was in the process of upgrading to lighter components so no biggie, but in order of probability (and cost), I'd check/replace: 

Cables
Cable housings
Chain
Derailleur hanger
Cassette
Front chainrings
Rear shifter
Rear derailleur

Two brand recommendations: Jagwire makes some great cable/housing kits. Secondly, the 1:1 ratio of SRAM rear shifting gives you more tolerance before you have to fine-tune.


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## ErickKTM (Jul 29, 2004)

Brand new bike, I increased cable tension at the lever, which seems to have fixed the problem. 

Thanks


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