Replacing Jockey Wheels in rear Derailleur – do I need to use Locktite?

[ianrauk]

Please allow me to volunteer my services!

Well that's not a suprise is it

 

[Smokin Joe]

Please allow me to volunteer my services!

Me too.

Mind you, it was a very long time ago on a Benelux derailleur. And they were crap.

 

[Peter Salt]

Huh. Sounds like an unusual incident - quite surprised how many people came forward with similar episodes.

Wear wouldn't cause this - even if the pulley bearing was dry and draggy, the derailleur is designed so that the bolts would tighten more - not come loose. Any chance you backpedalled excessively on that ride?

Maybe whoever did the assembly/service, stripped the thread off the bolt or cage?

In any case, answer to your question: You don't need to use thread locker on the pictured bolts, because they came with some sort of compound already on them. If they were bare - it's still not mandatory, but definitely won't cause any harm - as long as you don't use some really strong stuff.

 

[Smokin Joe]

Huh. Sounds like an unusual incident - quite surprised how many people came forward with similar episodes.

In half a century of cycling, I've either experienced or seen every part of a bicycle break, fall off or fail at one time or another.

 

[gbb]

They weren't tightened or assembled properly.
You will be hard pressed to find anyone on this forum who has suffered the same. I would say your problem is as rare as hen's teeth.

Errr, exactly this happened to me.
Why would it happen ?, who knows, you'll ( the wider forum and OP) never really know but not tightened correctly in the first place is most likely.
Managed to scoot home about 5 miles, it happened, fix it, move on.

 

[cool_hand]

Wear wouldn't cause this - even if the pulley bearing was dry and draggy, the derailleur is designed so that the bolts would tighten more - not come loose. Any chance you backpedalled excessively on that ride?

Maybe whoever did the assembly/service, stripped the thread off the bolt or cage?

No back pedalling here.

It's possible the thread on the bolt was damaged on assembly as it was over-torqued. I will check to see if the thread on the cage is damaged when I fit new bolts/wheels but I think it's unlikely.

 

[cool_hand]

Update: have inspected the thread on the cage and it is damaged. I put the new bolt in and there is play in the thread when threaded in. Don't think there's a BODGE JOB™ that can fix this so I'll have to order new cage plates. Whilst I'm waiting for parts to arrive there are some other jobs I can do on the bike. School boy error – have leant my lesson.

 

[gbb]

Update: have inspected the thread on the cage and it is damaged. I put the new bolt in and there is play in the thread when threaded in. Don't think there's a BODGE JOB™ that can fix this so I'll have to order new cage plates. Whilst I'm waiting for parts to arrive there are some other jobs I can do on the bike. School boy error – have leant my lesson.

Itonically you hit the nail on the head, the fact there's loctite on the bolts is actually because the side plates are quite thin, fewer threads to engage, so you really don't want to overnighten and strip those threads. The locking compound helps you, just nip the bolts up, compound will prevent them coming undone.

 

[Peter Salt]

Update: have inspected the thread on the cage and it is damaged. I put the new bolt in and there is play in the thread when threaded in. Don't think there's a BODGE JOB™ that can fix this so I'll have to order new cage plates. Whilst I'm waiting for parts to arrive there are some other jobs I can do on the bike. School boy error – have leant my lesson.

Bugger. Depending on what model is it, you may find that an entire new derailleur will be just marginally more expensive than the cage plates. A used one may even prove cheaper.

 

[Ajax Bay]

Bugger. Depending on what model is it, you may find that an entire new derailleur will be just marginally more expensive than the cage plates. A used one may even prove cheaper.

On the assumption the OP has ST-6700 STIs there is a wide range of RDs that would be fine.
Worth considering whether the next question will be: can I get a shorter low gear somehow. Answer: replace this semi-stripped one with a GS.

Chart Magic output: Here are the compatible parts in the selected category:
RD7900 - Shimano RD7900 Dura Ace Double 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]
RD6700 - Shimano RD6700 Ultegra 10-speed Double Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]
RD6700A - Shimano RD6700A Ultegra 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]
RD5700 - Shimano RD5700 105 Double 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]
RD5701 - Shimano RD5701 105 Double 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]
RD7800 - Shimano RD7800 Dura Ace Double 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here]
RD5600 - Shimano RD5600 105 Double 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]
RD6600 - Shimano RD6600 Ultegra 10-speed Double Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]
RD5703 - Shimano RD5703 105 Triple 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]
RD4601 - Shimano RD4601 Tiagra Double 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]
RDR35010 - Shimano RDR35010 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here]
RD4603 - Shimano RD4603 Tiagra Triple 10-speed Rear Derailer - Full compatibility - [Chart] - [Shop Here] - [Note]

 

[cool_hand]

FYI: ULTEGRA RD-6700-A SS G (Short Cage)
Levers are 105

 

[Peter Salt]

Looks like each plate is around £18-20. But you can get an entire derailleur for £25-35, dependant on condition.

 

[Gunk]

Any ideas why my jockey wheel fell off?

Because the tightness of the bolts was probably never checked. With regular use, stuff becomes loose, it’s good practice to regularly go around the bike with Allen keys and just check everything is tight.

 

[cool_hand]

Because the tightness of the bolts was probably never checked. With regular use, stuff becomes loose, it’s good practice to regularly go around the bike with Allen keys and just check everything is tight.

Thanks for your contribution but the reason why the jockey wheel fell off was because the thread on the outer cage was damaged.

 

[Gunk]

Thanks for your contribution but the reason why the jockey wheel fell off was because the thread on the outer cage was damaged.

But you did ask why it fell off