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[Closed] Difference between Shimano ROAD external BB and Mountain BB please?

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[#716560]

Just bought some Shimano BB's off a guy on here and they are all ROAD.

They fit OK, but what is the difference between these and the mountain ones that i have as std.

Ta

Dave


 
Posted : 17/07/2009 9:49 pm
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The road cups are a bit wider.


 
Posted : 17/07/2009 9:50 pm
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Bugger!!!

cheers Simon


 
Posted : 17/07/2009 10:03 pm
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If you have a 68mm BB shell it doesn't matter, just use 1 less spacer (each cup is 1mm bigger).

If you have a 73mm one you're a bit stuck.


 
Posted : 17/07/2009 10:05 pm
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just what I have found out

OK for my Cotic but not for my Alpine or Ventana


 
Posted : 17/07/2009 10:08 pm
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would a road one be better than an mtb one assuning you have 68mm shells?

I am assuming the road ones are wider because they deal with far more pedal torque?

just a thought


 
Posted : 17/07/2009 10:34 pm
 Smee
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How about no spacers on the 73mm?


 
Posted : 17/07/2009 10:57 pm
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IME, it's more the fact that the threaded part of the BB is narrower on the road BB than the MTB one. As a result, I use a Dura Ace BB on my steel hardtail and it's been in there for two years with no issue, but I wouldn't use one on an Alu frame, where this issue is more likely to **** up the alu BB shell threads.


 
Posted : 18/07/2009 4:09 am
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threads look the same length, the cups are 1mm wider each.

Smee, that would work for the drive side only but not the non drive side, plus but i am using a BB mounted DRS chain device so I can't remove a spacer


 
Posted : 18/07/2009 6:10 am