Rear derailleur mounting bolt retention

[quixoticgeek]

I've been having issues with shifting recently, as I'm on di2 it's not cable based, so reasoned most likely cause for a change would be the mech hanger is out of alignment.

Today i lay the bike down on the living room floor and went to undo the Rear derailleur mounting bolt. I had expected it to be tight, and I'd need to put some effort into it. It turned really easy. Like it was partially lose. When I reinstalled it i made sure to torque it to about 9Nm. My question is. Should I consider a drop of loctite on the bolt to make sure it doesn't come lose again. If it happened in the middle of a race it would be pretty terminal.

It's a steel framed with an integrated mech hanger, in case that makes any difference.

J

[hatler]

It certainly wouldn't go amiss.

When was it last tightened and how many miles have you done since then ?

[quixoticgeek]

It certainly wouldn't go amiss.

When was it last tightened and how many miles have you done since then ?

August. And a couple of thousand kilometres...

J

[hatler]

OK. A dab of LocTite, the right torque, and clock another 2000km and check the tightening torque again.

[robgul]

OK. A dab of LocTite, the right torque, and clock another 2000km and check the tightening torque again.

Make sure you use the appropriate LocTite - some "there for ever" glue!  Can't remember off-hand which one you need - IIRC it's blue.

[mzjo]

OK. A dab of LocTite, the right torque, and clock another 2000km and check the tightening torque again.

Make sure you use the appropriate LocTite - some "there for ever" glue!  Can't remember off-hand which one you need - IIRC it's blue.

Loctite 243 is the blue one for threads on fasteners that you would want to undo normally. Its stronger cousin is IIRC Loctite 270 which at least in France is green (although some other markets may have a red version). This can usually be undone normally with a bit more force; it goes with a bit of a snap. (in a demoltion workshop I usually used a length of tube - 80cms or so _ to avoid having to exert myself on 8 and 10mm bolts!) Warming it quite gently does soften it but you might not want to do this necxt to a Di2 dérailleur. Over this there is the "bloc press" (don't know what they call it in english) which is 60x (604?) which you might want to avoid! It's not meant as a thread lock!

Various tool and industrial suppliers have their own threadlockers which usually come somewhere between 243 and 270 and are for volume considerably cheaper. They tend to be red, same as the "bloc press" which doesn't lead to over confidence. Loctite market 8ml bottles that are sold in auto centers but sometimes difficult to find, supply irregular. It's the cheapest way to get it other than knicking it out of the workshop DAHIKT