Hello peeps,

Was just mulling this over….

I have a 68mm BB shell mtb with a knackered crank, can I use a roadie compact double and remove the outer ring? I have about 15mm of crank arm to chainstay clearence at the moment so I really can’t see why not. Will reduce the Q factor a lot I guess?

Anyone tried this? Any thoughts.

What about chainline?

Assuming you have sufficient Crank and chain ring – Stay clearance it should be fine, depending on the PCD you won’t be able to go for really small chain rings (Probably upwards of 38?) but you can simply up the sprockets tooth count relative to that to get the required gearing…. But yeah, in principle it should work…

someone on stw uses a campag chainset…

Yea on a tinbread (it got nicked IIRC?)

Looked cool, much nicer than the average MTB chainset.

Road BB cups are approx 1mm wider than the equivalent MTB ones. I’ve done it before, but be aware that it’s best to use a road BB. Mount the chainring on the outer position and it’ll run fine (using a compact so 34 T).

I used an ultgra chainset for a bit on my swift. It was fine as I played with the spacers on my rear hub to adjust chainline. But as schmiken put it you need to put the chainring on the outside on most frames as there isn’t as much clearance as on a road frame.

I’m pretty sure Sam at singular has put a few road chainset on his bikes.

Road BB cups are approx 1mm wider than the equivalent MTB ones

Presumably you are talking about external bearings here….

To OP – you won’t die if you use a roadie compact. I use one during the winter when the hardtail gets turned into a 1×9 commuter.

Presumably you are talking about external bearings here….

Yes indeedy! If it is a square taper you will have to watch out for frame/crank clearance. It can be fine, but may hit your frame if you’re unlucky.

Cool,

I have a truvativ stylo GXP crank at the mo which has seen better days and keeps loosening. Chianline not an issue as the rear sprocket can move in at least 1/2 and inch. I have a spare GXP road BB and thought of narrowing the Q-factor with a road SRAM GXP compact and run 34t to 19t on the 29er, within 1/2 a gear inch of my current 32t 18t setup. I also have 0.5mm axle shims so I can pack out the axle if needed. Time to find a 2nd hand red or force compact in 180mm or 177.5!

Thanks for your input guys.