tkm

My memory is a bit fuzzy on what's compatible with SRAM offerings.

Basically, I'm building a drop bar gravel bike from an aluminum hybrid frame. I'm fortunate in that it has a 68mm BB and both disc and canti/vbrake studs (probably will go with disc)

Anyhow, I have a lot of 10 speed SRAM road parts. I have a bunch of 9 speed SRAM mountain. Ideally, I want to run a Red compact crank, Force FD, 10 speed Force brake/shifters.

Just stuck on the rear derailleur part. Would like to use an 11-34 cassette so that means I need some type of 10 speed SRAM mountain RD, but which one? I'm assuming a 9 speed X9 or X0 RD won't work with the 10 speed brifters, correct?

I know it's all in getting the same cable pull but not sure what's what in the 10 speed mountain world in terms of RD's or if folks prefer one over another. Thanks.

veganbikes

It sounds like you might want to ask the mods to move this towards bicycle mechanics this is the mountain bike subforum. Sram 10 speed road I think is usually Exact Actuation so if you find mountain stuff that is also Exact Actuation you should be fine.

tkm

That's what I get for posting on my phone as I thought I was in that forum. I think my searching led me astray.

veganbikes

Not a problem you can just ask the Mods to move it, they handle that stuff all the time. I don't think I could ever go to this forum on my phone other than just to look briefly.

cb400bill

Thread moved from MTB to Mechanics.

Kontact 

9 speed MTB is not compatible. When 10 speed came out SRAM changed road and MTB to the same standard. Buy a cheap MTB derailleur and you'll be fine.

tkm

That's what I figured but couldn't remember.

What about the 2x10 front mountain derailleurs? Will a 2x10 X7 work with the Force 10-speed brifters (could not find the pull ratio for FD's)? My Force FD won't work as it doesn't swing out enough for the large chainring on my crankset (running a mountain crankset since a road crankset's Q factor put the arms waaaay too close to the chainstays for my liking.

tFUnK

Anything with "Exact Actuation" will work with respect to the pull ratio. Stay away from ESP or X-actuation.

Edit: But some of the MTB RDs have a smaller total chain wrap capacity so make sure you get one that covers your gearing.

Kontact 

Probably. But what was "too close" on the road crank? If it isn't rubbing, it isn't rubbing.

tkm

A few mm. I could bend the arm enough with my hands to get it to almost hit the stay. Under power I'm afraid it would hit. That was with a 2x10 SRAM road crank, which (as I understand) has a wider Q than a Shimano road crank. I currently have a Deore 2x9 on it (removed the inner-most small ring). Ordered a cheap NOS 2x10 X7 front derailleur to see if that works.

Kontact 

That looks okay to me. The crank doesn't flex inboard on that part of the pedal stroke.

tkm

Still worries me being that close, especially with SPD's on and how close my shoe will come to the stays as well. I may try it but if the X9 FD works on the setup, I'll likely leave it with the Deore crankset as it has a much wider Q-factor.