Bottom bracket

[Melalvai]

Last year in May, my bike was going 'clank clank clank'. The bottom bracket was failing...I didn't order one right away because I couldn't afford another bike repair that month. We kept tightening it every few days. But before the new one came in, the old one had BROKEN. It took them an entire day to carefully chip the pieces of the old bracket out of my frame without damaging the threads. (The bike is 15 yrs old...I have replaced every single component except the fork & stem.)

A couple weeks ago I heard a familiar 'clank clank clank'. "It can't be the bottom bracket again," I thought, "because that is new." But the more I heard it the more convinced I was that is exactly what it was.

I took it in, we tightened it, and I headed off. 'Clank clank clank' I heard, very softly. I turned around and went straight back to the bike shop. And ordered a new bottom bracket.

I've ridden ~5000 miles since getting this one, pulled some awfully heavy loads on a regular basis. So, is it me, or is this normal wear and tear for a bottom bracket?

[OakLeaf]

Is it sealed bearing or ball bearings?

I don't think it's normal wear. But ball bearings and their races will wear pretty quickly if they're too loose or too tight, and sometimes they have to be checked periodically because the hardware will loosen up on its own. (Heavy loads will encourage that to happen.) By the time you have a perceptible clunk, the races are already damaged and the whole component will need to be replaced.

[DebW]

Have you been tightening the cranks on the spindle, or the bottom bracket in the frame? When it clanks, is it just a noise, or is the bottom bracket shifting in the frame or are the cranks loose on the spindle? Could the threads in your frame be stripped or munged?

[Melalvai]

Is it sealed bearing or ball bearings?

Uh...sealed?

I don't think it's normal wear. But ball bearings and their races will wear pretty quickly if they're too loose or too tight, and sometimes they have to be checked periodically because the hardware will loosen up on its own. (Heavy loads will encourage that to happen.)

Heavy loads...yup...

Have you been tightening the cranks on the spindle, or the bottom bracket in the frame?

I haven't been tightening either on a regular basis, but after talking to my bike mechanic friend I will start doing that every 6 mths or so. When I took it in this week, we took it completely out, cleaned and greased things, and put it all back. So we tightened both the cranks and the bottom bracket.

When it clanks, is it just a noise, or is the bottom bracket shifting in the frame or are the cranks loose on the spindle?

Something is shifting because I can feel it as well as hear it.

Could the threads in your frame be stripped or munged?

Definitely possible. Remember the old bracket had to be painstakingly chiseled out of the threads of the frame!

[DebW]

Is this an Italian bike? Italian threaded bottom brackets have right hand threads on the right hand (fixed cup) side, which, because of the direction of rotation, can loosen themselves. If so, be sure your mechanic uses Loctite on the right side threads. I'm still confused if you have a sealed cartridge bottom bracket or an adjustable cup-and-cone bottom bracket with loose bearings. When you took it apart, did the bottom bracket come out as one sealed unit (spindle inside a cartridge) or as a separate spindle, cups, and ball bearings? It's not normal for a bottom bracket to need repeated tightenings, unless it is Italian.

[Kano]

Hmmm, bottom bracket -- would this like some grease too? I still have some after my wheel hub greasing project! I'm pretty sure little Trek has 25 year old grease in there, just like in the wheel hubs! Am I better off having a pro do this job, or will I be okay doing it myself?

Karen in Boise

[Melalvai]

Is this an Italian bike? Italian threaded bottom brackets have right hand threads on the right hand (fixed cup) side, which, because of the direction of rotation, can loosen themselves. If so, be sure your mechanic uses Loctite on the right side threads. I'm still confused if you have a sealed cartridge bottom bracket or an adjustable cup-and-cone bottom bracket with loose bearings. When you took it apart, did the bottom bracket come out as one sealed unit (spindle inside a cartridge) or as a separate spindle, cups, and ball bearings? It's not normal for a bottom bracket to need repeated tightenings, unless it is Italian.

Definitely not Italian. 1993 Specialized Crossroads.

Last year we replaced the original bottom bracket with one with sealed bearings. (I know this because I took it out today.) Though it was making the same noise as last year, I'm not convinced that the problem is the bottom bracket because after replacing it today, I hear the tiniest little "clink clink clink"....

At least I know I have a new good bottom bracket, so whatever is making that noise, the pedals won't be falling off the bike.