Hollowtech II BBs question

[e-rider]

Are all HTII BBs compatible with HTII chainsets (ie. not the one it came with)?

According to Shimano they are generally not interchangable so for example a Shimano 105 5600 BB and a Shimano 105 5700 BB are not the same spec and will therefore not work with 5700 chainsets (or 5600 chainsets) if you get what I mean?

This seems crazy to me becasue once a groupset is 3-5 years old the BB is no longer available to buy!

 

[TheDoctor]

I'm using a Sora chainset with a 105 BB (and the other way round on another bike) so it's not all that critical.
I expect Mickle will be along with a definative answer soon...

 

[Nebulous]

My understanding is that you can fit any hollowtech BB. They just have upgraded bearings and lighter components in the fancier ones. I have an old Tiagra crankset a 4500, with 4600 BB because that's what my lbs gave me, and I haven't had any issues.

 

[VamP]

HTII is a standard, so all HTII external cups are compatible with all HTII cranksets. That includes those not manufactured by Shimano.

 

[the_mikey]

I replaced a Tiagra 4500 series BB with a 105 BB with no problems (or noticeable difference).

 

[smokeysmoo]

+1 for the above. I changed a DA BB to an Ultegra one due to price and availablity. As VamP says, HTII is a Shimano standard, so therefore any HTII cranks will work with any HTII BB's

 

[2Loose]

Tiagra HT2 chainset with Ultegra HT2 BB here. No problems at all.