Can worn jockey wheel bearings cause shifting problems?

andyeb

I've just replaced the chain and rear derailleur cable outer. Shifting/indexing with the old chain was OK, but it had done 5000 miles, had worn past 0.5% and was getting rusty in places. I had already changed the inner cable a few months prior after it failed on me on the way to work.

I'm having real problems getting the gear indexing sorted, despite following a number of different videos on YouTube, including this one: <http://www.youtube.com/watch?v=SkzvfCaIbyQ&gt;

Gear behaviour simply isn't consistent when the bike is on the stand and it skips gears on the road, especially when going over bumps.

When I was replacing the chain, I noticed the was quite a bit of sideways play in the top jockey wheel. But I don't know if this is normal or not. The teeth themselves are not worn. Can this cause iffy shifting?

The rear derailleur shifter has got quite stiff recently (one of the reasons I changed the gear cable outer). I suspect this may also be related, but how I'm not sure.

Anyone got any ideas on how to troubleshoot this?

thanks,

Andrew

desweller

When you're changing the cables, you should change the outer housing. That's the bit that wears and influences shifting quality the most. If you've pulled a dirty cable through the housing then that's also a sure-fire way of getting it full of crud.

The play in the jockey wheels is normal. You can check the derailleur condition by unclamping the cable and manually moving it through it's range of motion.

Gurner

Is it just the shifter that's stiff? Can you move the derailleur by hand smoothly?

Play in the top jockey is usual for Shimano; the float allows for smooth shifting.

centimani

Go back to basics before getting too deep. Remove wheel and refit, making sure its central. I had a similar thing, just couldn't get the blooming thing adjusted after replacing parts. At some stage, I took the wheel out for something, put it back...it worked as though nothing was ever wrong. Must have been misaligned perhaps.

Cable routing, make sure it's correct. I've misrouted a RD cable between the adjuster and clamp once, similar problems.

andyeb

DesWeller wrote:

When you're changing the cables, you should change the outer housing. That's the bit that wears and influences shifting quality the most. If you've pulled a dirty cable through the housing then that's also a sure-fire way of getting it full of crud.

Agreed - ideally I would have liked to have changed both at the same time, but I didn't have the parts/tools for the full job, but needed to do an emergency repair of just the inner cable.

Perhaps I should junk the whole lot and start again?

The play in the jockey wheels is normal. You can check the derailleur condition by unclamping the cable and manually moving it through it's range of motion.

Thanks - that's very useful to know. I tried pushing the derailleur through it's range of motion - it seemed OK but perhaps slightly stiff?

Also - how does one set the tension screw in a derailleur correctly?

thanks,

Andrew

andyeb

Oh - and do you guys grease your cables? The inner I used claimed it was "pre-greased". I've found conflicting information online about whether you should or not, as well as the correct type of grease to use.

nicklouse

Try reading the info on Parktools. As it covers it all.

You did size the chain correctly.

You did clean the parts.

You did open up the cut outer?

mamba80

If you ve checked any friction between inner and outer rd gear cables, then i suspect that after 5k the cassette is worn and the new chain is skipping across the worn sprockets.

do you experience probs in all gears or just on the most commonly used ones?

JamesB

in contrast to above I`ve recently fitted a new set Tacx jockey wheels to a Campag Veloce raer mech taht was shifting sloppily and erratically and it has been totally transformed, nice clean smooth shifts. Had about 5k miles use too, top pulley was very wobbley, new one yes side play but much reduced