SRAM wide road cranks on MTb

[SSCC]

Anyone installed SRAM wide road cranks on a MTb frame? They can be used on 68 and 73 mm BB shells. I can speculate about chainring chain stay clearance so not looking for those opinions but for someone that’s actually done it. 

[DieselnDust]

Q-factor isn’t wide enough to clear the chain stays hence I haven’t bothered to try.

cant get the chainline aligned either

Edited May 14 by DieselnDust

[SSCC]

2 hours ago, DieselnDust said:

Q-factor isn’t wide enough to clear the chain stays hence I haven’t bothered to try.

That actually isn't true. Crank arms will clear chain stays no problem. Maybe you are confusing Q Factor with chain line.  

[DieselnDust]

43 minutes ago, SSCC said:

That actually isn't true. Crank arms will clear chain stays no problem. Maybe you are confusing Q Factor with chain line.  

 Nope not confusing them. Qfactor -20mm will give you an idea of distance from inner cranks arm face side to side.

the distance across the chainstays of an Mtb must be about 10mm less than the cranks inner face distance to clear the stays while riding (leaves 5mm clearance) 

some bikes have stays with compound bends and the curvature of the cranks won’t match that of the chainstay meaning there could be less clearance closer to the pivot in the area where the front derailleur used to sit.

with road and gravel cranks the q-factor is often <160mm with distance between inner faces around 140mm +_ 3mm (some exceptions) but still can achieve 52mm chainline through positive or negative positioning of an offset chainring.

 

sram road wide has a q-factor of 150 which leaves even less space for chainstay clearance on an Mtb. Chainline is 47,5 mm, even narrower than 142x12 mtb except maybe a 26er.

so you would have to be more specific around which cranks on which frame with what bb you’re trying to achieve this combobulation.

 

PS to qualify my comments . I have fitted a longer axle road hollowgram crank to a Mtb frame and got it to work. But that’s because the hollowgram system allows a high degree of modularity. SRAM road wide is much more restrictive in positioning (use of spacers) and allowable frame clearance. It is dependent on the mtb frame whether it will fit and then have sufficient clearance to actually work reliably.

Edited May 14 by DieselnDust

[SSCC]

14 minutes ago, DieselnDust said:

the distance across the chainstays of an Mtb must be about 10mm less than the cranks inner face distance to clear the stays while riding (leaves 5mm clearance) 

That helps thanks. i guess it does depend on the frame. Just measured mine and road wide cranks will clear the chain stays on my Mtb with 5mm of clearance. Pretty sure a zero offset chainring will fit up to about a 40 tooth. So not ideal boost offset but it may work. Currently have a 42 3mm offset.

[DieselnDust]

2 minutes ago, SSCC said:

That helps thanks. i guess it does depend on the frame. Just measured mine and road wide cranks will clear the chain stays on my Mtb with 5mm of clearance. Pretty sure a zero offset chainring will fit up to about a 40 tooth. So not ideal boost offset but it may work. Currently have a 42 3mm offset.

I’m assuming you have a hardtail?

[SSCC]

9 minutes ago, DieselnDust said:

I’m assuming you have a hardtail?

Yes hardtail. Trying to reduce Q factor as MTb Q factor bothers my knees. 

Edited May 14 by SSCC