Bicycle Mechanics - Mtn Bike Crankset on a Road Bike?

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View Full Version : Mtn Bike Crankset on a Road Bike?


higgit
08-27-07, 02:45 PM
Hi,

This is my first post. I am a retiree who has become addicted to cycling. My wife calls me obsessive; she's right.

I have a 2006 Specialized Sequoia Elite. My age is 68 and I do 50-100 mile club rides in a hilly area with hopes of doing a trip like Mountains-to-Sea in NC or the Blue Ridge Parkway before I have to use a walker.

I have had difficulty with long, over 10% climbs so I replaced the 11-25 (9 speed) that came with the bike with a 11-32 Mtn bike cassette (Deore) to go with the 52-42-30 Sugino triple crankset.

This has made climbing significantly easier and I am very happy with the extreme 30/32 ratio. However, what I gained in climbing, I have lost in ability to keep up with the better riders in my club because the gap between (cassette) gears has gone way up. I realize that I need the close ratios of a 12-23 cassette.

So, I thought: why not install a 44-32-22 mtn bike crankset (Deore XT) with a 12-23 cassette. That way I would have both the hill climbing capabilty (22/23 extreme overall ratio) and the close ratios for level paceline riding. What I would give up is the higher speeds from the 52 wheel, which I am happy to do because I seldom, if ever, achieve (level, wind-free) speeds of over 22-24 mph. And, going downhill for me is more about applying brakes than cranking.

First, technically and mechanically, can one use a mtn bike crank (Deore XT) on a Sequoia frame (9 speed)? Any issues with bottom brackets, etc.?

Second, will it work? Will I meet my twin objectives of: climbing capability and close ratios? Has anyone done this?

Any help will be greatly appreciated. Thanks. Ted


Mr Pantani
08-27-07, 03:22 PM
A mountain crank would work fine - though you likely will need a new bottom bracket just to make everything seamless. Additionally, you'll possibly need to swap out your front derailleur for one with a smaller radius, such as a mountain derailleur or possibly a late-90s Shimano RSX road derailleur (I've got one if you're interested) :). Otherwise, sounds like a plan.

orange leader
08-28-07, 10:41 AM
Why not just order new chainrings? I would think it would be cheaper, and you would get similar if not better results because you can pick exactly the size rings you want.

You don't even have to replace all of them, maybe just the outer two, or the higher two or the lower two, your call.

If you go with that Mtn ring setup that you mentioned, you might be spinning out, as you'll be loosing about 10 chainring teeth per pedal stroke in the big ring.


rmfnla
08-28-07, 02:12 PM
A mountain crank would work fine - though you likely will need a new bottom bracket just to make everything seamless. Additionally, you'll possibly need to swap out your front derailleur for one with a smaller radius, such as a mountain derailleur or possibly a late-90s Shimano RSX road derailleur (I've got one if you're interested) :). Otherwise, sounds like a plan.

Mountain FDs are not compatible with road shifters.

Besides, cage radius isn't that critical; the one he has should work just fine if it's situated & adjusted properly.

Iowegian
08-28-07, 04:25 PM
Cage radius may not be absolutely critical but I've seen cases where it does matter. Specifically, trying to use large road rings with mtb FD's can cause trouble with adjustment since the derailleur has to be mounted quite high to avoid contact with the largest ring.

melville
08-28-07, 04:47 PM
Is this Samba weegie? Do you, too, always carry a bike in case of luftkuhler breakdown? Neither do I. I do carry a surfboard in case global warming is real.

Do they have Rants here?

Later

Mel

rwp
08-28-07, 04:52 PM
What about something like a Sugino xd with 28-38-48 (or 26-36-46) rings. These will work fine with the existing front derailler. They're square taper but I think Nashbar sells an ISIS trekking crank with similar rings if that's what you need.

HillRider
08-29-07, 10:43 AM
What about something like a Sugino xd with 28-38-48 (or 26-36-46) rings. These will work fine with the existing front derailler. They're square taper but I think Nashbar sells an ISIS trekking crank with similar rings if that's what you need.
This is probably your best bet and you can even change the granny ring to a 24T.

Shimano makes a 12x27 9-speed cassette that is closer ratioed than your 12x32 and still gives a very nice low gear with a 24 or 26T granny ring.

BTW, you could change the 30T granny ring on your current crank for a 24T to get a better low gear and use a 13x25T 9-speed cassette to get close gears and a decent low gear.