Jockey wheels

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frogatthefarriers
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Jockey wheels

Post by frogatthefarriers » Sat Mar 21, 2020 10:10 am

I need to replace them on an NX 11 speed. A question in two parts:-
1) The jockeys are thick-thin. Do they need to be? I’m asking because, on every muddy ride the chain jumps over by one link, so the thick teeth engage the thin slots in the chain and make it rattle.
2) They have 12 teeth (I s’pose they’d have to have an even number). Is that critical? 11 tooth gives lots more options.
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slarge
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Re: Jockey wheels

Post by slarge » Sat Mar 21, 2020 10:42 am

I think that means you’re running 12 speed, so sorry, I have no idea, but I’ve always wondered why jockeys have teeth, when they only guide and tension and don’t have to mesh with the chain

Lazarus
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Re: Jockey wheels

Post by Lazarus » Sat Mar 21, 2020 11:00 am

thick thin would obviously need to be even or they wont work -otherwise it wont make any difference what number you use - though it will alter the chain length but i doubt it will be enough to require any changes or even be noticeable.
I have always just bought ebay CNC specials from china for a few quid and never had any issues- the set on my commuter have done a few thousand miles without issue.

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whitestone
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Re: Jockey wheels

Post by whitestone » Sat Mar 21, 2020 11:04 am

slarge wrote:
Sat Mar 21, 2020 10:42 am
I think that means you’re running 12 speed, so sorry, I have no idea, but I’ve always wondered why jockeys have teeth, when they only guide and tension and don’t have to mesh with the chain
Well they don't have to mesh with the chain in the same way as on a chainring or cassette but the chain does need to be guided both at top and bottom.

I think SRAM just went thick-thin as a sales ploy, no technical requirement. I've both Shimano and Hope jockey wheels and have yet to lose a chain within the jockey arm. I suspect the teeth are very worn so slip under tension, it will be obvious when you get a new set. Either replace with SRAM NX specific or check on CRC for compatible jockey wheels.
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frogatthefarriers
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Re: Jockey wheels

Post by frogatthefarriers » Sat Mar 21, 2020 11:32 am

whitestone wrote:
Sat Mar 21, 2020 11:04 am
I suspect the teeth are very worn so slip under tension, it will be obvious when you get a new set. Either replace with SRAM NX specific or check on CRC for compatible jockey wheels.
They could be, but it's always happened, even when they were new. The mud'n'grass wraps around and clogs them up.

I can see that if the top pulley fitted tighter within the links it could give closer control of the chain, so improve changing. It's a pain having to stop, get off, fish out my glasses so I can see, clean off enough muck so I can see the teeth, before finally jumping them back.
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Mariner
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Re: Jockey wheels

Post by Mariner » Sat Mar 21, 2020 5:00 pm


mfezela

Re: Jockey wheels

Post by mfezela » Sat Mar 21, 2020 6:40 pm

slarge wrote:
Sat Mar 21, 2020 10:42 am
but I’ve always wondered why jockeys have teeth,
The teeth ensure that even with some muck in the bearings / bushes, the jockey wheels still turn. Without teeth, in a worst case scenario, the wheels could jam solid. The chain would still run over the stuck wheels but with resultant horrendous wear to seized wheels.

Spinning jockey wheels also contribute to a measure of self cleaning for the bearings / bushes.

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