shimano hollowtech II

[RecordAceFromNew]

I didn't read all the replies but to answer the question:


the BB cups (bearings) and not all interchangable/compatible. I'm fairly certain the XTR cranks require XTR bearings - ie. XT ones wont fit.

I think it was me who responded to the OP's question with "...regarding your last question it should work with other bb bits and pieces in this diagram from a Hollowtech 2 XT chainset."

Unless I have misunderstood your comment I think they do fit, and to confirm I found below from Sheldon's site.

"Hollowtech II ® Two-Piece Cranksets: Shimano's latest top-of-the line system is a two-piece crankset. One piece is the combined right crank and spindle, the other piece is the left crank. Hollowtech II uses separate bearing modules that screw onto the opposite sides of the frame. Since the spindle is part of the right crank, there's no issue of compatibility. All Hollowtech II cranks work with all Hollowtech II bearing units."

There is one proviso, as ChrisWoody has inferred earlier, is that there are exceptions if one mixes road and mtb HT2 units. But since XTR and XT are both mtb groupsets that is not relevant to the OP.

Tundragumski you might be thinking about the earlier Octalink XTR's? IIRC all Octalink XTR chainsets are Octalink 1 (i.e. "road" type, despite the fact that XTR is Shimano's top mtb groupset...), while Octalink XT and indeed all non-XTR mtb Octalink chainsets are Octalink 2! But since the OP is and we are talking about Hollowtech 2 outboard bb's, this oddity doesn't affect him.

However for whom the oddity is relevant (and alas I think there are many, and I have always wondered why ShimaNO did it), one must NEVER mix an Octalink 1 bb with an Octalink 2 chainset or vice versa. They look very similar, but if one does the steel bb spline will chew up and kill the alloy crank. I think it must be common because all it takes is for the unwary to install an mtb Octalink 2 chainset on to a road bike with Octalink 1 bb, or vice versa, or buy the wrong replacement bb/chainset. The worst thing is that while initially the coupling might hold, the crank's chewed up alloy coupling will give under load without notice one day.

 

[02GF74]

just to confirmn, this is photo of the chains set, pretty sure that is hollowtech II .(and not octalink) ...... I hope.

 

[02GF74]

ok, linky no worky, so attaching.

 

[e-rider]

OK so I was wrong; not for the first time and probably not the last time. Sorry for crap advice.

So I have a question then, why don't hollowtech II FSA chainsets (called megaexo or something like that) work with Shimano BB bearings and vice versa?

 

[chriswoody]

Yep thats a Hollowtech II chainset you need an external BB like this one. However most of the MTB ones seem out of stock with Chain Reaction??

Instructions for fitting are Here.

 

[Cubist]

Not wanting to sound all "I told you so" but not all MTB specific BBs are the same. You can't use Shimano BB with Truvativ chainset. (As I found to my cost a year or so ago)

 

[02GF74]

^^ GREAT - THANKS - once i get the bb, i should be able to work it out - already fitted on of them just not on my bike.

 

[Flying Dodo]

OK so I was wrong; not for the first time and probably not the last time. Sorry for crap advice.

So I have a question then, why don't hollowtech II FSA chainsets (called megaexo or something like that) work with Shimano BB bearings and vice versa?

The FSA chainsets are slightly different sizes to the Shimano Hollowtech ones. My LBS tried and failed to mix and match.

 

[Svendo]

Shimano have made all chainsets interchangeable within the road and MTB hollowtech II ranges respectively, same axel diameter and same outer width (width between outsides of the BB cups when fitted). Don't know about interchangeability between road and MTB BBs.
FSA have a variety of different BBs, mainly because the outer widths vary. Especially between metal and carbon Chainsets. Don't know if the axel diameters vary, or if they're the same as Shimano. I seem to recall reading that some can be used with shimano BBs, but it may be a bit of a bodge.
Trutaviv/Sram road stuff all use the same BB, but the axel diameter is smaller than shimanos, you can get converters so after market BBs like Hopes can be used for their chainsets.
RaceFace presumably use same dimensions as Shimano, as after market BBs say they are shimano and raceface compatible.
No idea what Campagnolo do.
This is what I've gathered from having Shimano, FSA and Trutaviv chainsets and replacing the BBs for them.

 

[hondated]

You will also need a specific tool to fit them, ah the joys of upgrading!

Fair comment but you can fit them with a pair of expandable grips and by wrapping the the outside bearings in cloth. I did.