Rear Cassette skips just one cog

[BigonaBianchi]

I got the rear gubbins set so that the chain moves nicely across up/down one ata time and doesnt fall off either side....BUT...it skips over the second smallest cog on the way to the smallest cog (and only that ring) It doesnt skip on the way back to the third smallest cog. Ive done the limit screws and the cable tensionas best I know how...I cant see any broken teeth on the cog that get skipped...erm..??
TIA
Flummoxed of Sussex

 

[ianrauk]

You need to re-index the gears from scratch.

Here you go.

 

[BigonaBianchi]

Cheers mate...I've just followed the video but it still skips...it's like a tooth catches and hooks it over...I'll give it a few more tries.

It's the bit where he says if it works on one or will work on all of them...it works on one on mine and then all the rest except this one.

It's tradeable...just irritating.

 

[RWright]

I had that problem with 4th cog on one of my bikes. I had a bent cage on rear derailleur. I did some unbending and got it working correctly. You might can get it right with a B-Screw Adjustment.

 

[subaqua]

derailleur hanger slightly bent was the cause of the same problem on one of my bikes

 

[BigonaBianchi]

ok cheers...off to look at derailer

 

[mrandmrspoves]

Yes - you will never index the gears correctly if your mech hanger is out of kilter!

 

[BigonaBianchi]

I started from scratch and folled th evideo above again..set each limit screw and then the cable tension...but it still skips one cog. Now th ething is it cant be a damaged cog because now it skips on a different cog since i reset it. Im sure it's me not setting it as accuratly as I should...but i checked the rear mech in case it was bent...I havent had any knocks on it that would expalin a bent rear mech, and it doesnt look any different to normal to me.

The photo above is supposed to show how it clicks onto each gear perfectly until the secon smallest then it skips across to the smallest. I took this before resetting it...now it skips over the middle cog.

I am going to remove and repalce the wheel in case that does soemthing but it's in there properly for sure..

Cant see any cable kinks...and its all lubed well enough inside the casings.

Scratching head icon here.

 

[Nebulous]

It maybe that photo - but the derailleur cage doesn't look parallel to me.

I also had problems with a bent cage. Under power the blinking thing would change gear itself. I did a hilly local sportive/event last year and it really messed me up. I changed most of the drive train, and finally took a molegrip to straighten the cage and its been ok since.

 

[SatNavSaysStraightOn]

It maybe that photo - but the derailleur cage doesn't look parallel to me.. ...

+1
first thing I saw as well.

 

[subaqua]

+1
first thing I saw as well.

yup
that doesn't look quite right

 

[400bhp]

You might need new cables.

 

[mrandmrspoves]

New hanger or new mech. ...definitely not running straight.

 

[MattHB]

I had that problem with 4th cog on one of my bikes. I had a bent cage on rear derailleur. I did some unbending and got it working correctly. You might can get it right with a B-Screw Adjustment.

I want to see some un-bending!

 

[BigonaBianchi]

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it seems straight to me though...I got a staright edge and in seemed to line up...

if anything perhaps bend it towards the spokes a little bit??

Hmm...got cables coming so if thats isnt it then it has to be a bent mech...