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Gears skipping/slipping


Craigwt

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Hi All,

 

I have a problem where the gears on my bike seem to be slipping, almost causing me to fall every time as the pedal just gives way under my foot. This seems to only happen when I'm on the smallest cog at the back (maybe the second smallest as well). All the other gears work perfectly.

 

I installed the whole drive train myself, so I'm guessing it could be anything but my first guess is the chain length. I have attached pics of my derailleur in the largest cog and smallest, does this look like the chain length is right to you?

 

I'd really like to try fix this myself, and not have to resort to taking it to a bike shop. :) :)

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Edited by Craigwt
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When installing a new chain on a road bike, I was taught that on your largest chain ring and smallest cassette spocket the rear derailleur should be in a straight vertical line - I don't know if it is the same on a MTB.

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Do you work for Shimano?

No, Why do you ask?

 

Yes it looks like a too short chain.

Eish, This was a new chain with one link removed, when I had the extra link in the derailleur would fold back so far it would touch the cassette.

 

Are you sure the chain is correctly installed ,especially at the rear derailleur

I think so... If I look at my derailleur I don't see any other way that makes sense...

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I dont think that the chain is too long, but have you checked out the lower limit on the derailleur itself? Maybe giving that a bit of an adjustment might solve the problem. I remember when I setup my RD, I set the low and high limit, fine tuned and then had to do a fine adjustment on the low limit screw to get everything perfect.

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Do you work for Shimano?

 

How is this relevant to the thread/

 

Yes it looks like a too short chain.

 

How can you tell if it is too short? Doesn't look too short at all.

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My advice would be to check the derailleur hanger. A bent hanger is very likely to cause this behavior.

 

Also run through all the links in the chain to make 100% sure you don't have a stiff one somewhere. Just to be sure.

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I dont think that the chain is too long, but have you checked out the lower limit on the derailleur itself? Maybe giving that a bit of an adjustment might solve the problem. I remember when I setup my RD, I set the low and high limit, fine tuned and then had to do a fine adjustment on the low limit screw to get everything perfect.

 

I have double checked the lower limit, nothing seemed odd. I even backed it off a bit in case it was just on the verge of popping up to the next gear.

 

Next its either related to suspension, or riding over roughish terrain (I guess the two go hand in hand) because it does not constantly slip, I think I noticed it only happening when things got slightly rough... I went for a spin in the street and that seemed fine.

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Next its either related to suspension, or riding over roughish terrain (I guess the two go hand in hand) because it does not constantly slip, I think I noticed it only happening when things got slightly rough... I went for a spin in the street and that seemed fine.

 

Exactly what another hubber was experiencing with his Yeti. Up and down the street it was fine but as soon as the terrain changed a bit he would experience the skipping. His was on the upper range of the cassette though but still happened.

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So the cassette and chain are both brand new? How are the front chainrings? Slippage like you described normally happens with new/worn drivetrain components mixed together - IF everything else is aligned and adjusted properly.

 

Could also be ghost shifting if it's a suspension bike.

Edited by Brighter-Lights
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I've just been troubleshooting my road bike wih the same problem! After anticipating a new cassette and chain purchase, I decided to give it a super clean and lube...

 

Just found my LBS replaced the quick link with a 8speed one on my ten speed chain.

 

Possibly something to check.

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My advice would be to check the derailleur hanger. A bent hanger is very likely to cause this behavior.

 

Also run through all the links in the chain to make 100% sure you don't have a stiff one somewhere. Just to be sure.

 

Thanks, for the advice :) does the hanger need to be checked by a bike shop, I've read around, some people say you have to use a tool others say you can lay it on a flat surface... What do you think?

 

Had the same problem .Eventually my lbs replaced the cassette under shimano warranty

Was your problem only on a certain cog, or all the way through the gear range?

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