Fitting mountain bike running gear to road bike frame?

captain_vimes

I am building a bike for myself, to met my own specific needs, and I would like to fit a nine speed Deore to a Cannondale CAAD 8 road frame. Will the cassette and derailleur fit and work OK? I will run a single chainset but want a good spread of gears, hence the idea of fitting a mountain bike groupset.

Anyone tried this before?

Any reason why it wouldn't work?

lapavoni10

only difference I think is the dropout spacing on an MTB hub, but I guess you will be fitting the cassette to road wheels anyway...so most likley no issues.
If you were using the front derailer, you may need to check you can get it low enough for MTB chainset...but again you will be using a single ring.

captain_vimes

Yep, using road wheels on Shimano hub. So if the width of the cassette is the same as a road cassette I should be fine I think.

Now how do I check that?

Monty Dog

Plenty of road touring bikes e.g. Thorn/SJS Cycles are fitted like this - 9 speed Shimano MTB is intercompatible with their road groupsets. Problems only arise if you try run Shimano 10 speed MTB gear mechs with road levers - cable pull ratio is different.

StorckSpeed

Shouldn't be a problem, you'll need the Long Cage Rear Deraileur though.

crossed

StorckSpeed wrote:

Shouldn't be a problem, you'll need the Long Cage Rear Deraileur though.

No you won't, you'll be fine with a medium cage if not a short one.

rafletcher

Crossed wrote:

StorckSpeed wrote:

Shouldn't be a problem, you'll need the Long Cage Rear Deraileur though.

No you won't, you'll be fine with a medium cage if not a short one.

Indeed - probably short as the overall capacity will only be 20 teeth maybe.

As Monty says though, the bigger problem will be changing gears (I think!) as the STI lever won't (I think) have the correct pull for a MTB rear mech. Front of course no problem with a single chainring.

But..... why not use a hub geared rear wheel (though I guess dropout spacing may become an issue then)

StorckSpeed

Sorry - reading the original post again, Crossed and RAFletcher are right. Using a single chainset, you won't need the Long cage.

hypster

Captain Vimes wrote:

I am building a bike for myself, to met my own specific needs, and I would like to fit a nine speed Deore to a Cannondale CAAD 8 road frame. Will the cassette and derailleur fit and work OK? I will run a single chainset but want a good spread of gears, hence the idea of fitting a mountain bike groupset.

Anyone tried this before?

Any reason why it wouldn't work?

I've been running 1x10 like this on my training bike for a number of years now. I use an 11-32 XT cassette with a Sora short cage rear mech and up front an Ultegra triple crankset with a 42T chainwheel in the middle ring position. No reason why you couldn't use an MTB crankset but it does tend to push the chain line out a bit so there will be some stretch to the inner gears.

I have a bash plate in the outer chainwheel position as well because sometimes when changing down the block the chain may jump off if you are travelling fast downhill and bumps in the road cause the chain to flap. Bash plates for road cranks are few and far between now though so you might want to fit a chain guide like the one from Superstar.

captain_vimes

Cheers guys, all useful advice.

I think I will pick up a Deore 9 speed trigger shifter, medium cage mech and 11-34 rear spocket. I am planning to run a 42/44 road sprocket on the front so that gives me a nice range.
.

hypster

Captain Vimes wrote:

Cheers guys, all useful advice.

I think I will pick up a Deore 9 speed trigger shifter, medium cage mech and 11-34 rear spocket. I am planning to run a 42/44 road sprocket on the front so that gives me a nice range.
.

I presume you are planning to use straight bars then otherwise a Deore trigger shifter won't fit on road drops. You won't be able to get it round the hooks.

Ber Nard

If you do want to use drop bars, 9 speed road STI will work fine. In fact 10 speed shifters will work with a 10 speed cassette as long as you stick with a 9 speed MTB rear mech.

captain_vimes

Opps, should have been clearer. I will be running flat bars on this.

Once the frame has been sourced it should not be long before this one is up and running!

Thanks again all.

Vimes

mattsccm

If you are running flats then all you are doing is creating a 29er MTB.
Any issues only arise should you be mixing MTB stuff with road kit. Those have been mentioned above.
single ring is dead common nowadays in the MTB world.

maddog 2

sounds similar to my commuter

flat bar, 1x9, 9spd MTB medium cage mech, 9spd MTB shifters, 39t stainless ring, 11-28 cassette.