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Motivated said:
Basically what would happen if I put a Dura-Ace triple on my mountain bike?? Would a 9-speed chain shift properly on 10-speed rings?
Well, a couple things...

- BB width - Road is 68mm, and Mtn is generally 73mm. So you might not fit that way.
- Crank clearance - road cranks are narrower than mtn cranks. It probably won't clear the frame. So you might not fit that way
- chainring clearance - Road bike have larger chainrings, and your mtn bike might not have clearance. So you might not fit that way.
- Front deraileur height - You need to go higher because of the bigger chainrings, so you might not fit that way.

I think you get my drift that this is A Bad Idea(TM). Don't do it.

Why are you thinking about doing this? My guess is that you want to ride on the road, but don't have a big enough gear. My suggestion would be to buy a cheap or used road bike in that case. I figure a DA crank is what? 300?, you can get a new road bike for 500... not the best, but much more suited to the road.

GL,
-don
 

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Mantis, Paramount, Campy
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Yup, No Problem

Basically any chainrings will work with any chain.
Blehargh brings a good point with the BB though. As far as I know the DA bb is only for 68mm BB shells and some mtb frames use 73mm shells.
Other than that I'd say you're good to go.
I've used plenty of road cranks/chainrings on a variety of mtb frames with no clearance issues.
 

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On your left.
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Discussion Starter · #4 ·
I like road components

In many cases road components work better, are made better and cost less than mountain components, and they often weigh less too. (road cranks are also more available in 180mm) In this case I would actually need to get the smallest possible road rings because this is for an XC race bike - I need a 24t granny. I'm just investigating at this point and you are right - it doesn't look like it will work out - the good light road cranksets are typically double ring, and the triple ring versions weigh more than mtn cranksets and can't get down to a 24t or 26t granny.

I'm likely getting a Salsa frame which uses road standards on their mtn frame (68mm BB, bottom pull FD).

blehargh said:
Well, a couple things...

- BB width - Road is 68mm, and Mtn is generally 73mm. So you might not fit that way.
- Crank clearance - road cranks are narrower than mtn cranks. It probably won't clear the frame. So you might not fit that way
- chainring clearance - Road bike have larger chainrings, and your mtn bike might not have clearance. So you might not fit that way.
- Front deraileur height - You need to go higher because of the bigger chainrings, so you might not fit that way.

I think you get my drift that this is A Bad Idea(TM). Don't do it.

Why are you thinking about doing this? My guess is that you want to ride on the road, but don't have a big enough gear. My suggestion would be to buy a cheap or used road bike in that case. I figure a DA crank is what? 300?, you can get a new road bike for 500... not the best, but much more suited to the road.

GL,
-don
 

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Registered
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272 Posts
Motivated said:
In many cases road components work better, are made better and cost less than mountain components, and they often weigh less too. (road cranks are also more available in 180mm) In this case I would actually need to get the smallest possible road rings because this is for an XC race bike - I need a 24t granny. I'm just investigating at this point and you are right - it doesn't look like it will work out - the good light road cranksets are typically double ring, and the triple ring versions weigh more than mtn cranksets and can't get down to a 24t or 26t granny.

I'm likely getting a Salsa frame which uses road standards on their mtn frame (68mm BB, bottom pull FD).
You can get XTR cranks in 180mm and a 24t granny. Look it up at jenson. $299 for the '06. Just get that. It's going to be the lightest thing you can get, except for maybe '07. There's no reason for you to look at road components. You're making it way too complex. XTR will work great. Buy it and smile that you have the best. :)

GL,
-don
 

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Mantis, Paramount, Campy
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24T No Problem For Road Triple

They typically use a 74mm BCD for the inner ring, same as the ols mtb 'standard' so you can run any size ring on there from 24T on up, or if you get creative you can use 'chainrings' as small as 13T.

A bigger issue, depending on the terrain you race on, is that the smallest middle ring you could run is 38T.
 
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