Hollowtech II Bottom Brackets

enoonan

All,
Just wondering if the Shimano Hollowtech II bottom brackets are all the same sizes just with better bearings?
Would the 105/Ultegra work on a Tiagra chainset for instance or are they group specific?

Thanks in advance

Eoin

omri

enoonan wrote: »

All,
Just wondering if the Shimano Hollowtech II bottom brackets are all the same sizes just with better bearings?
Would the 105/Ultegra work on a Tiagra chainset for instance or are they group specific?

Thanks in advance

Eoin

I'm not sure about tiagra but I've been using BB from higher group with my 105 cranks few years ago. I think they will match it's just the price that differs between them.

seamus

They're all interchangeable. I think even the MTB ones will fit road bikes but I could be wrong.

gman2k

seamus wrote: »

They're all interchangeable. I think even the MTB ones will fit road bikes but I could be wrong.

Yeah, I've an XT HT2 BB on a road bike fitted to a triple Sora chainset.
The only difference in moving between MTB to road is the length of the inner shell, which you will probably have to change.
AFAIK all the road HT2 BBs are interchangeable (but prob not Dura-Ace)

Also, they are a piece of Pi$$ to change for the DIY home bike mechanic!

enoonan

Thanks lads.
Thats a great info to have. Most appreciated.

Eoin

funkyjebus

gman2k wrote: »

Yeah, I've an XT HT2 BB on a road bike fitted to a triple Sora chainset.
The only difference in moving between MTB to road is the length of the inner shell, which you will probably have to change.
AFAIK all the road HT2 BBs are interchangeable (but prob not Dura-Ace)

Also, they are a piece of Pi$$ to change for the DIY home bike mechanic!

Im using a dura-ace on my ultegra, once its HT2 it will work, except for MTB as described above.

And they are a piece of p$$ to change, but if doing it yourself i'd recommend a torque wrench.

omri

gman2k wrote: »

Yeah, I've an XT HT2 BB on a road bike fitted to a triple Sora chainset.
The only difference in moving between MTB to road is the length of the inner shell, which you will probably have to change.
AFAIK all the road HT2 BBs are interchangeable (but prob not Dura-Ace)

Also, they are a piece of Pi$$ to change for the DIY home bike mechanic!

For the mountain bikes there are some spacers to be put with the BB cups. For road bike you don't put any.

gman2k

omri wrote: »

For the mountain bikes there are some spacers to be put with the BB cups. For road bike you don't put any.

All depends on whether you have a 68mm or 73mm shell (for MTB), if you have an e-type front mech, or other devices attached to the RHS.
BBs generally come with 3x2.5mm spacers to allow for combinations of the above!

zil

I'm just wondering if anyone knows if the the xtr m960 follows this rule of all hollowtech BB's being the same. The chainset in question is notorious for having different bcd on the chain rings so just wanted to double check on the bb.

SurferDude41

With a Hollowtech 2 bottom bracket, it's important that the B/B shell on your bike is Chased and faced. Otherwise the bearings won't be aligned properly.

http://www.youtube.com/watch?v=kEz4K8SCl2Y