rear mech width - jockey wheels and jockey wheel bolts

SSBonty · Aug 23, 2007

Is there any width differences between the cages between 8 and 9 speed shimano rear mechs in terms of the jockey wheels they accept? I've been sent a 9spd wheel by a shop instead of the 8 i ordered, is it going to be too narrow? Or will it mess something else up - there will be an 8sps jockey wheel as it's partner.

Also - what are the widths for 7/8/9 spd jockey wheel bolts? They have some ally ones here:

http://www.billys.co.uk/english/group.p ... kp44s64b35

but there are 3 lengths listed - is it long for 7, medium for 8 and short for 9spd? might do a group buy and post them cheaply if anyone wants a set but not pay twice as much in postage (couldn't find post price but probs expensive)

Ian

jim-laden · Aug 23, 2007

Will not stand up in court!

I'm only using my uncertified logic, but your summation about decreasing bolt size for 7,8,9sp makes sense as the chains are narrower. As for jockey wheels I don't think you'll have a problem so long as it's the bottom one you are replacing and not the fancy floating top wheel(shimano mechs).

Ps cannot gaurantee the validity of info supplied!

Jim

andrewl · Aug 24, 2007

I'm not aware of any great difference between 8 and 9 speed Shimano derailleur cage widths and have been running 8 speed chains on M952 derailleurs for years with no dramas at all.

The only diference that I was aware of was the number of jockey wheel teeth from memory 9 has 11 teeth, 8 has 10.

Tallpaul · Aug 24, 2007

I ran a Mega9 rear mech with an 8sp IG chain and cassette for ages with no problems.

SSBonty · Aug 24, 2007

Yeah, I'm happy running 8spd drivetrains with a 9spd rear mech, and lots of shops/websites etc say this is fine - the chain easily fits over the wheels, and evidently the 9spd mechs aren't narrow enough that they stop the fatter 8 spd chains going through. Unfortunately I am replacing both jockey wheels! Anyone know why the number of teeth goes up with the number of rear cogs? And as no-one has siad definitely don't use a 9spd jockey wheel with 8 spd mech and drivetrain, I guess I can give it a go... Thanks for your replies!

Ian

Tallpaul · Aug 24, 2007

I don't think the tooth sizing on the jockey wheels changed, the 9sp jockeys are just bigger. I think they did it to make them run a bit smoother. They'll be fine on an 8sp mech.

rear mech width - jockey wheels and jockey wheel bolts

SSBonty

Devout Dirtbag

jim-laden

Retro Guru

andrewl

Senior Retro Guru

Tallpaul

SSBonty

Devout Dirtbag

Tallpaul

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