The Beacon Message Board

After having an alarming moment during the 200k Audax, where my rear mech started playing up - I think it may be time to replace the jockey wheels.

Anyone know what a good replacement would be?

It's a Shimano 10 Speed - Dura ace 7800 mech.

I'm no expert but I'd be surprised if they needed replacing, I dont think I've ever replaced any.

What was happening John?

Got this clack, clack, clacking sound - thought a spoke had gone. Phil said he saw the mech sort of jumping backwards and forwards. This only happened once - but with quite a way to go, I was dreading having a mechanical!

One of the jockey wheels doesn't really spin freely - thought maybe the bearings were going in it.

I had reset the mech the night before - because it had been sticking slightly in the middle range of gears - I tweaked the Hi limiter screw a little - maybe this was a little off - but the gear changes were smooth enough the night before...

It's not very often you have to change jockey wheels---a lot of gear changing probs come from stiff links in the chain--this can cause the rear gear cage to jump. I suggest give everything a good cleaning and lubricating. I've seen some jockey wheels worn really badly but still working fine. If the freewheel locks up it has the same effect---how old is the equipment ? A few drops of light oil sometimes works.
Good luck.

Andy M wrote:It's not very often you have to change jockey wheels---a lot of gear changing probs come from stiff links in the chain--this can cause the rear gear cage to jump. I suggest give everything a good cleaning and lubricating. I've seen some jockey wheels worn really badly but still working fine. If the freewheel locks up it has the same effect---how old is the equipment ? A few drops of light oil sometimes works.
Good luck.

It's only a year old. I had completely cleaned and relubed the bike the night before the Audax. The chain is newish too - KMC. I'll have a look at the links to see if any aren't moving freely though - thanks.

It's probably just some crud that's making the jockey wheel stiff that you could clear with WD40 and a thin sharp thing.

Quoting from another forum:
"Don't expect them to spin freely as you describe. Those with sealed bearings will not do so unless the seals are worn out. The ceramic bearing type used by Shimano won't do so. Look for a smooth rotation free of obvious rough patches"
This has happened to me on my old bike (a long way down from Dura-Ace, mind!) and a good old clean/lube of the whole mech was what sorted it out.

Your jockey wheels will last longer than almost anything else on your bike. My TT bike has a rear mech that's 25 years old, and the jockey wheels spin perfectly.

Sounds to me like something much more simple: cable adjustment. If the cable tension isn't right, the chain will jump and crunch, and as the chain prevaricates about which sprocket it wants to be on the rear mech will lurch forward and back. Cable tension is easily messed up by maintenance -- accidentally turning the barrel adjuster, moving the way the outer sits against a stop somewhere, freeing up a previously stiff/gunged up bit of cable, etc. A worn chain and/or sprockets will give rise to the same sort of symptoms, but you'd have to be doing a lot of miles to get serious wear in a year.

Maybe I can rule out the jockey wheels as the cause.

The bikes done 4235 miles since last June - maybe time for a service.

Thanks for the suggestions eveyone.

Sounds to me that the rear mech might have been catching the spokes on the rear wheel ?

It is actually worth replacing jockey wheels every so often, not because they stop going round ( they will probably keep going round forever ) but due to lateral wear that makes for poor shifting . If you check the side to side movement of the top wheel and it is greater than 2mm then it is worth replacing and should tighten up shifting gear and help keep the drive train running real sweet EVEN if your running campag.

Metal Fatigue wrote:It is actually worth replacing jockey wheels every so often, not because they stop going round ( they will probably keep going round forever ) but due to lateral wear that makes for poor shifting . If you check the side to side movement of the top wheel and it is greater than 2mm then it is worth replacing and should tighten up shifting gear and help keep the drive train running real sweet EVEN if your running campag.

OK, John. I consider myself put in my place. However, the closing shot was wide of the target: the 25-year-old rear mech on my TT bike is Shimano DuraAce (it predates the arrival of the indexed era that put an end to mix and match).

You sly old dog George, I know it was a cheap shot but well fenced my good man. ( I thought it would be fitting to use english from the era of George's rear mech ).