Hi

I've tried looking for a definitive answer to this but haven't come across it.

I'm not very experienced with thread lockers but is there any problem with using grease simultaneously (particularly when parts such as BBs come with some TL on it already) ?

My impression from different threads is that using grease renders the TL compound ineffective but I'm not sure how that would work.

Hope someone can help,
george

They are not compatible. Clean threads before using threadlocker

Grease wil keep the threadlocker from "locking". If you are going to use threadlocker, clean all grease and oil off of both the male and female threads. Solvent washing the parts is recommended to assure they are dry and grease-free prior to using the thread locker.

Don't use threadlocker. Clean threads and grease or oil are all you need for any bicycle part. Most TL is put on parts to avoid liability in case its installed incorrectly and comes apart and hurts someone, but its unnecessary.

Pre-applied threadlocker (already cured) should have no issue when used with grease. It's far less effective than something like Loctite applied just prior to assembling the parts. However, liquid Loctite will not cure properly in the presence of grease. The more experienced mech's on this board advise always greasing bottom bracket cups which precludes the use of Loctite. I'd have to agree. A properly tightened bottom bracket cup will not come loose and the grease will assure quiet operation.

Loctite will not cure in the presense of air.

Not always. The FSA SL-K crankset comes with a tube of threadlocker. If it isn't used, even with the crankset installed and torqued correctly, the NDS crank arm will work loose in a very short period of time.

I have seen a product presentation on loc-tite where they described the action of the product.
Small crystal shaped peicies are formed when you try to break loose the threads, The edges of the
crystals dig into the surface of the metal. The different grades (red blue) are a function of crystal size.

I would beleive that lubricants would reduce the effectivness of loc-tite. Assuming you could even get
properly cured loctite into the presence of grease. After all they clearly state you start with clean threads.

I too was confused about this issue. I recently replaced a cup & cone BB with a cartridge one on a steel frame. I asked an otherwise respected mech. at the LBS about how to install it and they said to grease the BB tube threads and use a bead of blue 242 Loctite on the first couple of threads of the cartridge. This didn't seem right to me so I greased the inner half of the BB tube and the last couple of threads on the cartridge thinking that the 2 wouldn't come in contact with each other this way.

That is not thread locker, but assembly compound. Loctite 641.

Mostly the same principle though (anaerobically cured epoxy). The pre-applied threadlocker (that San Rensho is commenting on) that comes on some bottom bracket cups (and brake mounting screws and chair assembly screws) is an entirely different thing. It's often just a nylon patch that gets mostly removed as the parts are threaded together. It will keep an untightened fastener from falling out as quickly as it otherwise would though.

thanks for all the responses, very helpful