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

[cool_hand]

But you did ask why it fell off

And if you'd read through the rest of the thread you would of seen that I'd confirmed why it had fallen off:

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.

 

[Chislenko]

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]

Fair play that is some amount of research. I couldn't be bothered doing that much if it was my bike!

 

[cool_hand]

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.

Shifters are 105 ST-5700. Previous owner upgraded the group-set to Ultegra 6700 -A but kept the original 105 shifters.
The cost of a new outer cage is around £13–£16 and as l already forked out on new jockey wheels and bolts I might as well finish the job!

 

[cool_hand]

Fair play that is some amount of research. I couldn't be bothered doing that much if it was my bike!

It's (Chart) Magic. See link at top of post.

 

[Chislenko]

It's (Chart) Magic. See link at top of post.

Right, would I be showing my age, lack of interest in all things IT if I said I had no idea what chart magic is 😟

 

[cool_hand]

When I install the new jockey wheels (bushes) - do I grease them or use oil?

 

[Gunk]

When I install the new jockey wheels (bushes) - do I grease them or use oil?

I’ve always used some light oil