Road chainset on MTB ?

trek_y · May 1, 2012

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 ?

Dead Rats · May 1, 2012

what size is the BB shell on the Scapel? I think the vast majority of modern road chainsets are 68mm only :!:

suburbanreuben · May 1, 2012

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.

hamster · May 1, 2012

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.

Dead Rats · May 1, 2012

I've run Shimano 600 instead of Deore DX too but modern issue would be BB shell width

suburbanreuben · May 1, 2012

hamster":p9aqja63 said:
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.

hamster · May 2, 2012

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.

suburbanreuben · May 2, 2012

hamster":3svxdhns said:
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 .

bm0p700f · May 2, 2012

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.

trek_y · May 3, 2012

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.

Road chainset on MTB ?

trek_y

Dead Rats

suburbanreuben

Old School Grand Master

hamster

Retro Wizard

Dead Rats

suburbanreuben

Old School Grand Master

hamster

Retro Wizard

suburbanreuben

Old School Grand Master

bm0p700f

Senior Retro Guru

trek_y

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