Installing a new bottom bracket.

[nameused]

Ok so I finally got my bottom bracket (sealed bearing) in the mail. During the time I've been waiting for it, I've been looking up how I should grease the threads and any ways to make a good seal for it. What I got from my research was that I should wrap the threads with teflon tape and then grease both the cups and the threads on the bike when installing it. However when I got the bottom bracket in the mail it has a plastic cup on the end and it says not to apply grease to it. I don't think it would make much of a difference if I grease it or not.

So my question is should I use the teflon tape and what should I grease when installing the bottom bracket?

Thanks!

[JohnnyCO]

No Teflon. You can grease the threads but its plastic so its not gonna be so critical. That plastic cup will torque itself on there and corrosion shouldn't be such a factor with plastic threading onto a aluminum(assuming aluminum) thread. Just use proper torque which should be included with the new BB instructions. Always a good idea to chase threads of the BB shell to ensure good clean threads. Happy installation...

[nameused]

Yeah my frame is aluminum.
I might have found a problem. When I pulled off my old BB, there was water sitting in there. Any ideas where this came from and if its any problem?

[trevgbb]

Be very careful with plastic cups, it is very easy to ruin the splines if over torquing, and if they say no grease on the plastic, they probably mean it.
Also doubt if there is room for tape in the threads as they are usually a tight fit and could interfere with assembly.
Water ingress, most BB's, and I see now head sets, usually have some sort of sealing which is semi effective unless very aggressive conditions,
but down the seat tube if a hardtail is possible.
Or do you use a power washer, no. no.

[nameused]

(11-06-2010, 04:34 AM)trevgbb Wrote:  Be very careful with plastic cups, it is very easy to ruin the splines if over torquing, and if they say no grease on the plastic, they probably mean it.
Also doubt if there is room for tape in the threads as they are usually a tight fit and could interfere with assembly.
Water ingress, most BB's, and I see now head sets, usually have some sort of sealing which is semi effective unless very aggressive conditions,
but down the seat tube if a hardtail is possible.
Or do you use a power washer, no. no.

I don't put it through any aggressive conditions. It just lives its life outside and gets hit with Hawaiian rain. I do have a hardtail, so that might be possible. And nope, no power washer for me

[JohnnyCO]

Finding water in the BB shell is common. Possibly coming from seat post and the wet environment.

[nameused]

(11-06-2010, 11:59 PM)JohnnyCO Wrote:  Finding water in the BB shell is common. Possibly coming from seat post and the wet environment.

Well I decided to look at my seat post today and there is no hole in the top. There is a small slot where the seat post clamp is, so maybe it gets in there.

[X-RAY]

its very hard to waterproof anything completely. this is why its important to tear down and relube things regularly. contrary to what the assemblers at walmart think, grease is cheap.

[JohnnyCO]

China-Mart says, "after this bike breaks cause you can't fix anything on one, time for your NEXT bike."

[nameused]

(11-07-2010, 02:34 PM)JohnnyCO Wrote:  China-Mart says, "after this bike breaks cause you can't fix anything on one, time for your NEXT bike."

Too bad its a Trek not a Next. But still pretty funny, I might say that to people with those walmart bikes now