On the fragility of bottom brackets

unscarred

Thanks to the lovely people in Evans Waterloo Road last night, I now have a new bottom bracket on my commuter. Cycling in this morning the bike felt noticably lighter than it has for several weeks, which makes me think the bottom bracket was on its way out for a while before it broke.

Now, I completely understand that parts break from time to time, but this is the second bottom bracket that I've broken in less than two years of commuting. This seemed to surprise the guys in the shop, so my question is:

Was I just unlucky?

OR

Am I such a super-strong, powerful and manly cyclist that ordinary steel is simply no match for me?

The Rookie

What BB? If its external the BB shell may need facing square as a bearing running out of true is a guarentee of early failure.

I'm sure the BB didn't 'break' but the bearings may have been worn!

Simon

desweller

Have you been pressure washing your bike or anything nasty like that?

unscarred

They were definitely broken, no doubt about it!

Neither were external, I think both were cup-and-cone style.

The first one I cracked the shell, so that my mechanic couldn't get it out of the frame. Fortunately it was a £25 ebay bike, so I just harvested what bits I could and junked it.

The second one I bent the axle by about 5 degrees.

And nope, I never pressure wash my bikes. I barely wash them to be honest, just the occasional wipe with a rag and oil. Maybe a sponge bath if they've been good.

The Rookie

were both new when you started, cup and cone is usually only used on cheap bikes, so are cheap and prone to failure just for that reason, also most get the grease washed out by any water coming in the frame (manufacturing holes, unblanked threaded holes or the seat tube) then exiting via the BB bottom drain (or side holes around the axle, worst still) if they are blocked.

Only time I've seen a BB axle bent was someone who loved to drop their bikes, the side loading on the axle (via crank and pedal) bent it.

Simon

vorsprung

So you bought the bike cheap, the BB broke and you replaced it with another cheap BB

And after a few more months of use it broke again

I would guess that the Shimano UN53 in my old single speed has done in excess of 20,000km and is still fine.

I suggest that you get ride of the cup and cone and fit a square taper Shimano sealed unit. They cost £10 to £20 new.

unscarred

vorsprung wrote:

So you bought the bike cheap, the BB broke and you replaced it with another cheap BB

And after a few more months of use it broke again

Not quite, the frame was unusable (without costly work to remove what was left of the BB) so I bought a whole new bike. I had no particular reason to believe the new bike had a cheap BB, but as it turns out it probably was.

I suggest that you get ride of the cup and cone and fit a square taper Shimano sealed unit. They cost £10 to £20 new.

That's what I've done now, see OP.

The Rookie

Not what your OP says at all is it, just says a new one!

Removing what is left of a BB is usualy pretty easy! I cut a cup and cone one out my duaghters frame, with a hack saw (4 cuts and broke it) in about 15 minutes.

Simon