Road crank on MTB Frame - Is it possible?

[philip.maree]

I am in the process of building a SS and I want to re-purpose a SRAM Rival Compact crankset since it has a 34T blade. I want o fit to my On-One Scandal frame. The BB Shell of the frame is a 73mm and I know that the road crank is designed to be used in a 68mm shell.

 

The spindle is shorter than a mtb crank but it is still long enough to fit through the shell and for the non drive side arm to be attached.

 

If I torque the crank to spec then it doesn't turn at. If I tighten it to the point where there isn't play it still spins nicely. But I am not sure if this would have adverse effects on either the BB or the crank.

 

Is what I am trying to achieve at all possible?

[Bike Mob]

what type of BB system are the two running?

[philip.maree]

what type of BB system are the two running?

External BB SRAM GXP

[Bike Mob]

one foreseeable issue is that you are exerting side load pressure on the bearings which will decrease their lifespan, if you reduce torque you may have side to side play, finding an ideal balance will be tricky.

[Bike Mob]

and your q-factor, and chainring clearance on your frame not an issue?

[droo]

If you fit it to a 73mm shell the right hand crank won't bottom out on the shaft spline, hence the tightness when you torque it up. This will make it wobble after a few hard pedal strokes, and the ends of the splines will round out. This also means that there's 5mm less of the spline to engage, which means that sooner or later it will fail.

 

Bottom line - find a 68mm shell to install it on, or don't bother.

[philip.maree]

and your q-factor, and chainring clearance on your frame not an issue?

2 Spacers on the drive side sorts out the clearance but the chainline is not to bad though.

[Bike Mob]

That's going to make matters worse effectively shortening the spindle more