Bottom Bracket problems.

Does anyone have any ideas about this one? I just bought myself an octolink bottom bracket, 73mm/113mm, all good until I tried to slide my XTR M952 chainset on. The splines on the axle are too wide :facepalm: Can anyone suggest an alternative or will I have to try and find a used one. Also, I need a 73mm but I,ve seen some that say 68 or 73, how does that work? It's for a 94 GT RTS if that helps. Thanks.

What you have there is the difference between Octalink Version 1 and Version 2.

The V1 BB has shallower splines and only fits V1 cranksets. This was only used on XTR and a few road cranks.

The V2 type of BB which it sounds like you have, was a later version which is compatible with practically all the other Octalink cranksets out there. Deeper splines you see...
They are still manufactured by Shimano too.

Your only option is to find a V1 specific BB, which will only really be an XTR BB. You'll be very lucky to find a new one but may find a decent used one somewhere though.

The 68 or 73 refers to the frame's BB shell width as measured in mm. Your RTS will most likely have a 73mm shell as was usual with GT bikes.
68mm BB shells are the more common width in general.

73mm Dura ace V1 bottom brackets can still be found at a fair price

WD

The 2 middles ones


G

Cheers guys, that's a big help at least I know what I'm looking for now. I better start looking for one :facepalm:

This thread might help a bit to : viewtopic.php?f=1&t=267607&hilit=bottom

If you want, pm your email and I will send you the 950 bb instalation instructions which show what spacers fit where to suit shell width etc.

Cheers,

WD

Ultegra BB-6500 fits and it fairly cheap. I sold a nice one for £15 last week on eBay.

Shimano 5500 and 7700 are available new in 109mm and 118mm lengths. The 6500 were available in the same length. So your chainline will be out.