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Jockey wheel problem


robster82
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I put a new chain on tonight in prep for tomorrows run, all gears running smooth on the big chain ring but when in the small everything goes really wonky! Looks like chain jumps off bottom jockey wheel.

Paul Mcd wants local hills tomorrow now I'm stuck in big ring, please help? 

P.s. I did clean dirt from the jockey wheels and there is a bit of sideways movement, not sure if this is normal. 

 

Cheers

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That's a bummer, Robbie!

It's always difficult to diagnose bike issues on the forum, but it's fun nonetheless :-)

1. Have you cut the new chain to the right length? When one small chain ring (front) & smallest sprocket (rear cassette), the chain should still be tension, with around 10-15mm gap between the chain & the upper jockey wheel!

2. Does you lower jockey wheel's (the one in question)" teeth" still good, by that I mean it haven't worn out?

3. Does the chain want to come off in all the sprocket selections or is it just when chain is on the lowest one?

I'm sure others will be along soon to chip in :-)

Good luck & if all fails, just stick it on the big ring & smash it up those hills :-)

Cheers

Chung

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This is the second chain on the cassette George,  I've had that problem before but this seems very different.

Chung, the chain was measured against the old one so should be ok and the jockey wheel teeth look fine. Yes the chain is coming off all sprockets very quickly! 1 turn of crank then chain is off jockey wheel and all out of line.

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A wee bit of movement is normal.

if your previous chain had stretched a bit, as they all do eventually, it starts to wear your cassette & chainrings. This affects your shifting.

could also be you haven’t fitted it right and you have a stiff link that’s causing it to jump.

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A bit of jockey wheel movement is normal...they also last quite a bit. I would say either small front ring or most probably cassette worn out (signs of teeth wear are normally shark fin/sharp edge appearance). You can always put back the old chain and see if that works for a temp solution.  

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Have you put the chain on right , have you adjusted the b screw, take them off and clean then note which  one goes to the top and correct direction of travel.

one of the wheels are designed to move to keep the chain in the right place 

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Just read this Robbie, this is a long shot but happened to me once. Tighten the very small Allan screw that holds  the outer rear mech plate to the inner plate. Other than that my suspicion would be rear mech knackered but worked with stretched chain ok.

suggest try your rear mech from summer bike ?

:)

 

 

 

 

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Cheers guy's, put my summer wheel/cassette on and still same problem. Narrowed it down to jumping off only in gears 1-5.

Chain is definitely on ok as everything runs sweet on big ring, no stiff links either. 

I've not adjusted any screws at all.

Thanks for the suggestions I'll have another play about tomorrow. 

 

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Robbie,

If all the above points have been checked & it's fine as far as you can see!

Then have you recently dropped your bike landing on the drive side? Or that the rear mech have had impact (knock) against it?

I suspect that your rear-mech hanger (the detachable part screwed onto the drop-out which your rear mech is attached to) might be very slightly bent.

Unfortunetly, the only sure & accurate way to check & fix it is with an "rear mech alignment tool", all good bike mechanic should have one :-)

http://www.chainreactioncycles.com/park-tool-derailleur-hanger-alignment-gauge-2-2/rp-prod149800?gs=1&pgrid=36427643173)&ptaid=pla-272543305852&utm_source=google&utm_term=&utm_campaign=Chain+Reaction-UK-PLA-PLA-All-DT-SE-Shopping+QLB+Generic+Desktop&utm_medium=base&utm_content=mkwid|sBeMgJ9J4_dc|pcrid|161850070953|pkw||pmt||prd|546386UK

Good luck!

Cheers

Chung

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(top(pulley) jockey wheel has more side-to-side wobble to allow gear change. lower(tension) has less)

Chung may well be correct re. hanger. It sounds like your chain line may be too extreme from front little ring to rear small cogs. This would matter if the lower jockey wheel is pointing outboard a little.

Can you post a photo from directly behind the bike in small/small? Our enormous minds may come up with an explanation which makes at least partial sense. Also post lateral shot of the cassette teeth. Overhead shot of small/small would be supercool too.

Also (apologies if you have done so ):?directional chain/correct chain speed/?removal and accidental swap of jockey wheels.

What's the groupset?

Alan

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Hi Robbie

I've only just seen this so hopefully you have now sorted it out.

If you haven't sorted it, check the jockey wheels again. Some lateral play is normal, however the bushes can wear out. This results in too much play which could affect the chain, in certain gears. 

If your jockey wheels are the type that have bearings ( eg SRAM) check they are all there - missing bearings can have same effect as above. It happened to me recently.

If it turns out to be a bent hanger, I have the alignment tool should you need it. Alternatively, replacements are cheap.

 

 

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Thanks again for the info and suggestions men, as soon as I get time my plan is to remove and inspect/clean the jockey wheels and take it from there. 

Everything has been kept the same,  11 speed kmc chain I have used before, no jockey wheels removed or any screws adjusted it was a straight swap.

Groupset is 11 speed Shimano 105 5800.

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excellent plan. My jockey wheels were totally seized after cross racing so they can malfunction.

Shimano pulleys should be marked "guide" for top and "tension" for bottom with directional arrows for correct replacement. Cheap replacements available on line.

but have you checked hanger alignmnent first? we await with baited breath......

Edited by Alan McLean
pulley should read guide
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I now have 'Jockey wheel induced insomnia' couldn't sleep with all these solutions going round in my head, so up first thing and started to tinker.

Hanger, to the eye looks in line, theres been no bumps to my knowledge.

Small chainring teeth look fine also, this doesn't get a lot of use being by hammered by the boggers.

All screws were tight and in place.

Cassette looks also in  good nic.

So stripped j.wheels to inspect and clean, the wee bush/roller thingy inside bottom jockey doesn't sit quite snug, re-assembled everything and there is a fair bit of lateral movement on both wheels. It looks like the bush has worn on bottom wheel allowing movement, the tension is then lost on chain causing it to jump off, Dooleys in the morning.

 

P.s I'm now running late for a wedding with a pregnant angry wife growling at me! 

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