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  1. #1
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    Jet 9 RDO w/ XTR M985 Race 28/40. Possible?

    Hey, there. Posted this in the drivetrain forum, but thought the group here might have had a similar question/experience.

    I'm wondering if anyone has successfully run a Jet 9 RDO frame with the XTR M985 28/40 crankset. The Niner website says the combination is not recommended. Bought the frame on closeout. Too hard to resist, but now I'm faced with the potential need to find new cranks (which is too bad because I really like the XTRs).

    Thanks!

  2. #2
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    Couldn't you change the rings to 38/26 to avoid any possible frame contact? Or is 40/28 your sweet spot and you don't want to give it up? I'm planning on getting a Jet 9 RDO as well and have some XTRs 38/26 waiting in the wings.

  3. #3
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    My understanding was that the problem is with the XTR Trail in 28/40, not the Race. The Race is a true 2x crank while the Trail is a 3x with the big chainring removed. True 2x or supposed to be ok because the large ring is a bit farther left then the middle of a 3x. Can you please post a link to where on the Niner website you saw this? I'm in the exact same situation as you and now you have me concerned.

  4. #4
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    Quote Originally Posted by wheel-addict View Post
    Can you please post a link to where on the Niner website you saw this? I'm in the exact same situation as you and now you have me concerned.
    Check out the very bottom. I'm pretty sure the 48.8mm chainline crank is the M985 race.

    Jet 9 RDO w/ XTR M985 Race 28/40.  Possible?-jet9rdo_spec.gif

  5. #5
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    Quote Originally Posted by onegymrat View Post
    Couldn't you change the rings to 38/26 to avoid any possible frame contact? Or is 40/28 your sweet spot and you don't want to give it up? I'm planning on getting a Jet 9 RDO as well and have some XTRs 38/26 waiting in the wings.
    I'd be ok with either 40/28 or 38/26. The problem with the M985 race double is the rings are an odd (proprietary?) bolt circle diameter. Only M985 race rings fit, and the only other size available is 42, which would be even worse!

  6. #6
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    Good point. And it looks like they are referring to the Race version in that link. It's a confusing comment though because Race is not available in 38/26. So, they are somehow referring to both Race and Trail at the same time. I wish there was a way to get a hold of Niner today to find out for sure. I can still cancel the order for the frame I just purchased. This could be a deal-breaker to go with the Jet 9 RDO for me.

    One think really odd is that Competative Cyclist seems to be specing XTR Race by default on the Jet 9 RDO frame when choosing a custom build.

  7. #7
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    I really hope you reconsider keeping your j9 rdo on order. It's one amazing bike, even without XTR cranks on it! I'm usually a shimano guy, but for this specific frame I chose a SRAM offering to take advantage of the bb30 cranks with pf30 bb. Why not just go with an xo or xx crank? If it makes you feel any better...I'm running an XT drivetrain with an x9 bb30 crank I got for dirt cheap at jenson. It shifts perfect and actually much lighter then I thought it would be. I just didn't wanna deal with adapters for the shimano cups. Figured one day I'd give the xx1 or xx cranks a try.

    Here's an afterthought...what about running an additional spacer on the drive side? I think the problem with the XTR is on some frames, the chainrings can rub the carbon. I asked my dealer about it before I bought the frame and said they've never physically seen these issues, but niner came across a few bikes that had problems. Could just be a few frames that were out of tolerance? I dunno , but don't give up on the niner yet!

  8. #8
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    Ok, I've decided to stick with the Niner. I was concerned about 28/40 chainrings being bigger than I wanted, so I'll sell them. I do want to keep the XTR front shifter. Are you running a complete Shimano drivetrain other than the X.9 crank? What front shifter/derailleur combo are you using?

    Quote Originally Posted by drz400sm View Post
    I really hope you reconsider keeping your j9 rdo on order. It's one amazing bike, even without XTR cranks on it! I'm usually a shimano guy, but for this specific frame I chose a SRAM offering to take advantage of the bb30 cranks with pf30 bb. Why not just go with an xo or xx crank? If it makes you feel any better...I'm running an XT drivetrain with an x9 bb30 crank I got for dirt cheap at jenson. It shifts perfect and actually much lighter then I thought it would be.

  9. #9
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    I dont have the bike in front of me right now, but i believe I have the M980 rear der and shifters. I lied, i actually have the XT front der only because I had a hard time finding the XTR direct mount version. I will be using the XTR if i can get my hands on one. Not because i think it will perform better..but only to keep everything matching.

    The only non shimano part on my drivetrain is the X9 cranks. I originally only bought them because Jenson had them on sale for 90 bucks shipped to my door with a coupon code. I wanted a true BB30 crank, so this was the best value i could find. the PF30 bb and BB30 cranks seem to be the simplest way to go. I actually might keep the cranks on my bike. I didnt realize how nice the X9 stuff was. They weighed only 700 grams not including the bottom bracket. Which is not much heavier then the XTR, and lighter then XT. I wouldnt be surprised if the x9 cranks with bb, weigh within a couple grams of the XTR cranks with the adapters. Ive run 100% xtr drivetrains in the past...and it feels exactly the same with the sram crank thrown in the mix.

    So yes..all Shimano with the exception of the X9 cranks. I wouldnt have it any other way at the moment. I could never get used to srams shift actuation. Even if i wanted to...the only way for me to shave anymore weight on most of the drivetrain is to go with XX or XX1. Even then, i dont know if it would improve feel or performance. The shimano stuff works so well, and may be disappointed in the end.

    You made a good choice! Youll love the jet9 rdo build. Any other questions, let me know!

  10. #10
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    good to hear the SRAM stuff is working out for you. i'm going to throw the XTR cranks on the frame just to see what the interference/clearance issue is. but i must admit, i do like the idea of going PF/BB30 and not dealing with adapters.

  11. #11
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    I was in the same boat. I love Shimano stuff; I've run XTR on my past bikes exclusively, but I wasn't super excited about having to adapt a BB/PF30 frame just to run an XTR crank, so I opted to run the XO 38/2whatever (tooth count escapes me) just to keep the BB/PF vibe going. As much as I love XTR, I have absolutely no regrets w/ the XO crank. It works perfectly with an otherwise complete XTR grouppo.

    I say do it!

  12. #12
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    glad I read this thread....I love shimano and wanted to go with XTR using 40/28 chain ring. But I was also disappointed Shimano did not make a 30 spindle for the PF30 bottom bracket to take advantage of the bigger spindle. I rode another bike with full XX and was amazed at how well the drivetrain shifted. So im not looking for XX or XO PF30 cranks and might have to go with SRAM for this RDO build.

  13. #13
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    I remember Niner coming out with being able to go ahead an run the xtr cranks on their full suspension models, but not hardtails. This was recent and it was not updated on their literature.

  14. #14
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    So what did you go with? I went with Sram XX 39/28. So far so good. It looks like a 28/40 XTR 2x10 race crank will fit. I've got room with the 39t.

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