Bottom Bracket Size

[PeterPi]

I've had the TSDZ2 fitted to my twenty year old bike for three years, and now I'm looking to move the kit to a new bike. Nothing fancy, but the problem is making sure I buy a bike with the correct size Bottom Bracket. I see things like this "Sealed, 68x122.5mm Square taper ". I get the 66mm bit but what does the rest mean.

TIA
Peter

 

[saneagle]

68mm is the length of the tube. That's all you need to look for. You'll be chucking the rest.

 

[PeterPi]

Thanks for that. I knew what the 68 meant, but the rest must be to do with the crank spindle, I suppose.

 

[Nealh]

122.5 is as you say the crank axle length , one can buy sq taper BB's with various axle lengths.

 

[Terol Jiang]

yes, 68/73mm is the bottom bracket length (also called BB size) of the bike, i also know there is also have BB100MM and BB120MM in the market. usually the length of the crankset is about 170mm, so what 122.5mm means? Curious!!