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XT rear mech jockey wheel bearings


marshace
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Took my rear mech (XT Shadow 12 month old) to pieces and cleaned it up.  Found the bottom wheel had a nice little sealed bearing in it that runs beutifully, the top one has a ceramic bush in it, and no matter how well I cleaned and lubed it, it simply does not run as smoothly as the bearing one.

Now the question:

Is this correct ?

Can I replace with both having bearings ? (Might help to go faster, less friction)

The KCNC ones that you pimp you bike with, do they both have bearings ?

Does XTR have both with bearings ?

 

I suppose many ar gigling at the thought of this minor amount of added friction, but I was just wandering.
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the KCNC one's will not last long at all. My SRAM X.O came with ceramic bearings and also did not last long, just get normal lx/XT ones/ 

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yeah u'll go faster on the downhill... Tongue

lol, i got the same setup on mine, and got the same issue, but i didnt really care about that...
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The bushing does not really spin but it should turn freely. Not sure if it will add any friction to slow you down... I have tried both with bearings and both with bushings and could not tell any difference.

 My take is to just replace them every three months with cheap Deore ones.
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Top wheel is a bushing sytem as it acts as a guide only .. the lower wheel has a bearing as it is under far higher loads ... info complements of previous discussions with "Go Lefty".. yes I know you are saying how can one take a person seriously who rides a bike with half a fork, but his tech knowledge is rather decent.

 

 

 

H

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The top pulley, called the guide pulley, needs a bit of lateral float in it to make the gear settings more forgiving and run a quieter drive train. The bottom pulley, called the tension pulley, doesn't need float but often needs a bit of offset biased to the left.

 

It is therefore easy to put a cartridge bearing in the bottom - these don't have float. However, do not assume that the ceramic or bronze bushings found in some pulleys are rubbish. They're excellent and there's nothing wrong with a bushing in this application.

 

Most of the bling bling pulleys have bearings top and bottom, taking away the float in the guide pulley. This shortens the pulley's life and requires more precise shifting settings - something that is not quite possible in dirty circumstances.

 

Further, metal is a poor pulley material and the best ones are the plastic/fibreglass ones.

 

Some aftermarket ones and from SRAM (I think) have ball bearings top and bottom. You'll find that these don't last long at all, in MTB applications. The grime quickly compromises the seal which wears down. This is evident if the pulley spins freely. It should have some drag otherwise it means the seal is kaput.

 

More money doesn't buy better pulleys.

 
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It should have some drag otherwise it means the seal is kaput.

 

?

 

More money doesn't buy better pulleys.

 

?

 

 

 

For once spending less is better smiley4.gif

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