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 Post subject: Road chainset on MTB ?
PostPosted: Tue May 01, 2012 12:18 pm 
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Not knowing much about road bikes is there any reason why I can't use a road BB30 chainset like SRAM Force on my BB30 Cannondale Scalpel ?
I want a carbon crank and intend to run a 1x9 setup so I can get an SRAM Force for a lot less than any of the MTB carbon BB30 chainsets and take off the big outer ring leaving the 34 which would suit my gearing. BB30 is a standard size I assume so are the spindle widths different or ?


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PostPosted: Tue May 01, 2012 2:02 pm 
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what size is the BB shell on the Scapel? I think the vast majority of modern road chainsets are 68mm only :!:


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PostPosted: Tue May 01, 2012 3:39 pm 
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The Q factor (distance to outer edge of crank where pedal screws in) is lower on road cranks. Road chain stays do not have to accomodate fat tyres so are narroweracross, allowing the cranks to also be closer to the centre line.
You may weell find the crank ends bashing the stays.


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PostPosted: Tue May 01, 2012 4:39 pm 
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I ran happily with Campag Veloce double cranks with a 111mm Campag BB on a Kona Cindercone, so I think you will be OK. However every frame is different - a very short-stayed frame is likely to be the worse case.


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PostPosted: Tue May 01, 2012 6:44 pm 
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I've run Shimano 600 instead of Deore DX too but modern issue would be BB shell width


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PostPosted: Tue May 01, 2012 7:25 pm 
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hamster wrote:
I ran happily with Campag Veloce double cranks with a 111mm Campag BB on a Kona Cindercone, so I think you will be OK. However every frame is different - a very short-stayed frame is likely to be the worse case.


In the old days you could just run a longer bottom bracket shaft to make the cranks fit. With BB30 you can't.


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PostPosted: Wed May 02, 2012 9:56 am 
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True, but 111mm is the standard road BB length for Campag double - so the point I was trying to make was that there seemed to be enough clearance from a 39T ring.

While the chainset and BB length would differ for BB30, the position of the chain ring relative to the centreline the same regardless of brand etc. With that chainring position there was enough clearance from the chainstay.


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PostPosted: Wed May 02, 2012 3:48 pm 
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hamster wrote:
True, but 111mm is the standard road BB length for Campag double - so the point I was trying to make was that there seemed to be enough clearance from a 39T ring.

While the chainset and BB length would differ for BB30, the position of the chain ring relative to the centreline the same regardless of brand etc. With that chainring position there was enough clearance from the chainstay.


Chainline is not the problem; Q factor is!
My Rotor cranks have a very low Q factor, some 10mm less than most other mtb cranks. I have 3 or 4 mm clearance between the end of the cranks and the chainstays. The road version is about another 10mm narrower. Go figure .


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PostPosted: Wed May 02, 2012 10:07 pm 
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No one can answer your question. You will simpley have to try and if it does not work try a work out why ad try a different crankset until it does.

Hope helpful I know but there are to many variables to give a definitive answer as I doubt many have tried. Take a look at Campag centaur as well they might be cheaper than SRAM Force carbon.


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PostPosted: Thu May 03, 2012 4:23 pm 
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Thanks for all the replies. :)
The Scalpel has a 73mm BB shell and the chainstays are quite wide to accomodate the rear suspension design so I guess that pretty much rules out the idea. Ah well back to trying to find a MTB BB30 carbon crankset without breaking the bank.


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