On a bike... where is it a good idea to use LOCTITE?

The two places I would use it are:

1. Disc brake attachment bolts
2. B-Screw on dérailleurs

Anywhere else seems unnecessary i my opinion. What do ya' say?

operator had a good rule in another thread: use it on the threads of bolts that are not to be tightened fully.

OK, that makes sense... now would you include bolts that close with locknuts?

Locknuts work by tightening against another nut or bolt, so they are tightned fully against each other; therefore, Loctite wouldn't be necessary.

How bout use it on stuff that keeps coming loose?

loctite is pretty general
loctite runs from keeping it from vibrating off to it ain't coming apart ever again (without heat) on small screws where you can't apply heat red loctite is permanate, blue you can usually get apart with wrenches if the bolt/screw is1/4/6mm or larger 222 purple is the handiest for keeping stuff from vibrating loose and common machine screw sizes

V-brake and canti attachment screws. Phil Wood BB cups. bk

Yes, I was reading the original post and about to write the same. Loctite... Which Loctite exactly ? "I have a red bicycle, what size tyre should I use?"

I occasionally use 538. This will never come apart again, unless you heat it with a torch. And assuming you've *properly* cleaned the parts before applying Loctite. I.e. cleaning and degreasing properly. Without proper surface preparation you might as well not bother with the Loctite.

It also depends a bit on the materials you're trying to bond. Steel is generally excellent with 538, aluminium is fine too. Nickel or nickel-coated materials are a bit iffy with 538. When in doubt, check the manufacturer's datasheet and application notes.

The OP's question to me sounds he has a solution (flask of Loctite) but is looking for problems to solve with it.

I usually use the blue stuff on spoke-nipples and crankarm bolts. Everything else on the bike has some locking mechanism like lock-nuts or lock-washers, so Loctite isn't really needed.

Actually don't own any and don't plan on it either.

Derailleur pulley bolts. +1 to the "bolts that don't get fully tightened" usage. In other words, very rarely.

The blue version (242, I believe) has come in handy for me when attaching a bottle cage that kept working its way loose. Also, has anyone noticed the blue substance that coats the first 3-4 threads on new Campy crank bolts? Looks like a threadlocking compound to me.

I don't think anything stronger than 222 (purple) is necessary for bike fasteners. It will keep things from working loose, but not stop you from loosening them on purpose.

I bought a used campy rear derailleur from eBay, and when I got it the low limit screw was stripped out. I had to drill it and EZ-out it to get it out, and when I did it was coated in blue loctite. Definitely overkill.

Blue loctite on adjustable stem bolts and or rear rack attachment bolts.

I have to wonder whether a lot of the bolts you see that come with Loctite pre-applied (e.g. brake fixing bolts, crankarm bolts, disc rotor bolts) are examples of engineering by the legal dept., or if it's really needed assuming you use adequate torque.

What bolts on a bike don't you tighten fully???Why have a bolt if your not going to tighten it,wouldn't a rubber band/string/duct tape work???

I don't use any on my bike,but I use plenty of it at work(automotive machinist).