Last week I noticed that my bottom bracket was fairly loose, so I thought nothing of it (it's an old Schwinn Le tour that's been converted), and went to the bike shop to get it tightened (I didn't have the tools). Anyway, so the guy tightened it, everything was tip-top until today. I noticed again that there was some play in the BB. Is this something that I should start getting worried about (the fact that is becoming loose, not the fact that it is loose)? I'm assuming those track stands and what not put a lot of pressure on it, but I'm trying to figure out why it would become loose in the first place? Is it in need of replacement (I sure hope not) or is there a problem with the frame, or what? The peeps at the shop tightened it down pretty well and it didn't have any play right after I got it out of there, but I guess it just got loose again.

Any help would be appreciated.

What kind of bottom bracket is it?

Modern sealed or old adjustable?

1. Are you sure its you BB? It could be your chain going slack. On a fixed gear, play in the chain can feel like a loose BB.

2. If it truly is your BB, its probably an old cup and cone BB. Those sometimes just don't stay tight. I had an old cup and cone BB on my first beater fixie conversion. I kept coming loose and I had to adjust it every couple or weeks. There was nothing visibly wrong with the BB, and it wasn't anything weird (like a French threaded). I've had other cup and cone BBs that stayed tight for thousands of miles. At any rate, if the BB is smooth enough and in good enough condition to justify not replacing it, I would just spring for whatever tool you need to adjust it and just check it every week or so. That will be cheaper than having the shop keep fixing it.

3. If you have a sealed cartridge BB, you could try some locktight on the threads, but I would really suspect that there is probably something wrong with it and it should be replaced.

4. If you really don't want to mess with it, just get a new BB....but before doing that you had better read a few articles about chainline.

I have an italian threaded cartridge bb that came loose once (Sheldon has a great explanation of why this counterintuitively should happen) . After hitting it with my torque wrench to the recommended spec it hasn't caused any more problems.

If it's Italian-threaded you might need to loctite it in there. Getting it out will, of course, suck.

i have a MASI with an Italian BB...Chrorus BB only came lose on me twice, and after I opened it up for cleaning. I used never-seaze when threading it everytime.

I forgot to mention that it is an adjustable type BB with wrench flats (so i don't need a pin spanner to tighten it).

It's def. play in the BB. Grabbing both cranks and trying to move them side to side gives you the feeling that the BB is knocking.

I went through a couple of old adjustable BB's with the same issues before giving up and putting a sealed cartridge in. now I never have a problem.

I'm probably gonna try and dig up a set of Phil Wood French rings and a UN72 for my old Pug - sometimes the stuff just doesn't stay.

Spend the $20 on a shimano UN53 bottom bracket. It will stay tight, last for years, and all you'll need to buy is the splined bb socket.

I've found that if you trackstand or resist stop a lot, and have an old cup and cone BB, the fixed cup can come loose, even on English or Swiss threaded bottom brackets. If it is the fixed cup coming loose, the solution generally isn't loctite; instead, find a shop with a Var30 fixed cup tool and have them crank the fixed cup on hard. A regular tool can't torque like this one, believe me. I've never had one work loose after this, be it French or English... actually, I've never had a French fixed cup come loose at all because I install all my fixed cups with this tool. I have had to retorque a couple of English fixed cups, tho. It's really probably not a purchase option for most cyclists, about 200$ Ithinks, tho they do show up on ebuy now and again.

eh, you'll probably need to loctite it. why not just ditch the bike and get a new chromed pista?