Jockey wheels

General cycling advice ( NOT technical ! )
Peterflane
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Jockey wheels

Postby Peterflane » 23 May 2018, 2:35pm

I have a 9 speed derailleur (Sora) with an 8 speed cassette (Claris) and need to replace the jockey wheels. Should I go with 10 or 11 tooth? Many thanks.

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cycleruk
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Re: Jockey wheels

Postby cycleruk » 23 May 2018, 4:18pm

Use the same tooth number that is current.
Leave getting old to others.

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The utility cyclist
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Re: Jockey wheels

Postby The utility cyclist » 23 May 2018, 4:33pm

you can use any, bigger is better.

Mr Evil
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Re: Jockey wheels

Postby Mr Evil » 23 May 2018, 4:59pm

The utility cyclist wrote:you can use any, bigger is better.

If you use bigger ones, you might need a longer chain. They will also be closer to the cassette, so you might have to adjust the b-tension screw. In the extreme, if there is no adjustment left then you wont' be able to use bigger ones at all.

Peterflane
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Re: Jockey wheels

Postby Peterflane » 23 May 2018, 8:54pm

Thanks for the replies. There were 11 on the ones I'm replacing and it seemed to work ok so I'll just change like for like.

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The utility cyclist
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Re: Jockey wheels

Postby The utility cyclist » 23 May 2018, 8:56pm

Mr Evil wrote:
The utility cyclist wrote:you can use any, bigger is better.

If you use bigger ones, you might need a longer chain. They will also be closer to the cassette, so you might have to adjust the b-tension screw. In the extreme, if there is no adjustment left then you wont' be able to use bigger ones at all.

IF you go to a 14 maybe, if you left no leeway at all, an 11/12 from a ten, no, the difference isn't enough to warrant even a single link.

Brucey
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Re: Jockey wheels

Postby Brucey » 24 May 2018, 10:28am

bigger is better in some respects but obviously you can't just whack huge pulleys in a standard mech without consequences. 10T ones will probably work OK but I'd stick with standard sized 11T ones.

An often overlooked aspect is that pulleys with odd-numbered teeth wear more evenly than ones with even numbered teeth, if the chain stays meshed with the same teeth for a long time (which it will do if the chain doesn't unship or the rear wheel isn't disturbed).

It isn't a bad idea at all to regrease the pulley bushings in new pulleys before they are fitted. I have even drilled the mounting bolts so that the pulleys can be regreased in situ, and they can last a very long time indeed if they are treated this way.

cheers
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The utility cyclist
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Re: Jockey wheels

Postby The utility cyclist » 24 May 2018, 2:27pm

Why on earth would you grease pulley bushings, it's simply not necessary, not at any level, a tiny drop of very thin oil or if you must but even then that's simply not required as it works perfectly fine as a dry system even on the bottom end stuff. :?

Brucey
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Re: Jockey wheels

Postby Brucey » 24 May 2018, 7:05pm

why grease? Well without grease, water and dirt gets in more easily. Unless modified to have a lube port it is very difficult to add more thin oil without washing more crud into the bushings, and if you put thin oil inside them it soon comes out again, even with the best seals presently available.

Needless to say the viscosity of grease is much higher than that of oil and (because the loads are low) even in slow-moving bushes like these you can make them work like plain bearings (think of car crankshafts etc) do i.e. the surfaces are separated by a film of lubricant and there is no wear at all.

Note that even plain pulley bushings fall into several types including

- steel on plastic
- steel on steel
- steel on sintered bronze
- ceramic on ceramic

they all share one feature; they last for longer if they are kept lubricated with clean lubricant, and unless you like stripping and cleaning the little beggars on a regular basis that is most easily achieved by greasing.

A chum of mine recently stripped down a mech that I'd put together ~15000 miles earlier with lots of grease in the pulley bushings and (despite total neglect in the meantime, and commuting use in all weathers) the pulleys were fit for further service.

In that mileage I estimate that the pulleys have gone round over 40 million times.

cheers
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MikeF
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Re: Jockey wheels

Postby MikeF » 26 May 2018, 10:47pm

Very recently I replaced the jockey wheels on my T661 RD. These have done a little over 10,000 miles. I can't remember if I've ever greased them - if so it would be only once. The guide pulley showed very little sign of wear on the bushing, but the tension pulley had noticeable wear. I replaced the tension pulley with an Ultegra 6700 one which has sealed bearings and looks a better construction. The guide pulley I replaced with a greased new one of the same type, although I'm sure the original would have carried on for longer apart from the teeth being slightly worn.
"It takes a genius to spot the obvious" - my old physics master

gregoryoftours
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Re: Jockey wheels

Postby gregoryoftours » 28 May 2018, 11:28pm

Best to replace like for like- if you go bigger can cause clearance problems with the tabs on the mech cage. No advantage in going smaller.

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RickH
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Re: Jockey wheels

Postby RickH » 29 May 2018, 2:35pm

Of course if you want to go big there is alway this. Yours for only £538.99! :shock:

Manc33
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Re: Jockey wheels

Postby Manc33 » 30 May 2018, 10:49pm

I reckon big ones give slightly impaired shifting over small ones. The RD-7700-GS was a notable example.
Only weird bikes are interesting anymore.

Brucey
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Re: Jockey wheels

Postby Brucey » 30 May 2018, 11:38pm

as well as obvious stuff like setup and condition, a lot depends on how the guide pulley interacts with the chain. IIRC RD-7700 was meant to be used with an asymmetric chain or something? That might have made a difference.

At the other extreme old Campag RDs (eg NR and earlier) were meant to be used with chains that had inner side plates that stood up above the rollers in the chain, so the teeth on the guide pulley didn't have to be very high to gain purchase. Modern chains are not like that, so the ability of the RD to push a modern chain around is very poor indeed unless a different guide pulley is fitted.

In modern RDs you can see quite large differences in design; check out this RD-5800 mech;

Image

the guide pulley teeth are simply enormous.... :shock: :shock:

To my surprise even when this RD is miles away from the sprockets the shifting is still pretty slick. That is with new 11s parts though; whether it stays that way for long is quite another thing.

cheers
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sufferingpete
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Re: Jockey wheels

Postby sufferingpete » 9 Jun 2018, 2:35pm

always replace the chain when replacing jockey wheels. I had an old chain jam in a jocky wheel which bent the rear mech into the wheel and bent the frame.