What’s the deal with a square tapered bottom brackets? One on the roadie has quite a bit of play in it, and it’s causing rubbing issues on the front mech now. It doesn’t look serviceable, so I resume it’s time for a new one. Can anyone recommend a decent one? I’d prefer one I can change the bearings in myself, but I don’t know if you can get square tapers like this?

Sorry, only other square taper I’ve owned went in the bin after a couple of months, not had to buy a new one before.

UN54 – £15 or so. Now have hollow axles so they don’t weigh too much.

Non-replaceable bearings but that’s the norm.

Sweet, cheers clubber. If thats the norm I’ll get one ordered.

Shimano UN55 is the latest one which has an alloy NDS retainer (instead of plastic). Under £20, should do several thousand miles on the road.

Ah, didn’t know about the 55 – good to hear (though I never really had an issue with the plastic lock rings.

Ah, in that case I’ll grab the 55 instead, anything to make it last a little longer! Makes the hollowtech on my full-suss feel so expensive.

And what’s the verdict on how to fit them? I’ve tried different variations on “put crank on, tighten bolt”, but generally within 6 months I’m seeing play in the NDS crank as the taper’s gone in the cranks 🙁

Clean threads in BB shell of frame, apply copper grease. Screw the cartridge into the driveside (LH threads of course), doesn’t need to be super-tight. Then screw in the NDS retainer, again don’t overtighten.

I then like to clean up the cranks (and tapers) whilst off the bike, then lightly grease the tapers and tighten the bolts pretty firmly with a 4 or 5 inch long allen key. Keep an eye on them for the first 3 or 4 rides, tightening a little if necessary, but just don’t overdo it!

that ‘metal’ ring on the 55 is softer than the plastic one on the 54!

but either way either is good, cheap and reliable