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Hi, quick question, will a 24-38 double chainring set up with shimano xtr fit on a 2010 air9?
I run a 22-36 but need some extra gears on the flat.

By the way, great bike!
 

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cabbgage said:
Hi, quick question, will a 24-38 double chainring set up with shimano xtr fit on a 2010 air9?
I run a 22-36 but need some extra gears on the flat.

By the way, great bike!
Cabbgage,

No, it won't fit. The new 2x10 XTR gruppo has a crankset with a 38t outer ring, however this crankset is based on their 3x XTR front crank, so the 2 chainrings are set in the small and middle chainring respectively. This is probably the same as what you're looking at and it's a no go. The 38 is too big to be mounted in the position of a middle chainring. The cranks designed around 2x gearing have a slightly different spacing, and therefor fit fine (SRAM will be making this chainring config for their 2x10 cranks from X7-X0 and it will work fine).

Steve
Niner Bikes
 

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Wow, that would be great if SRAM comes out with that gearing combo (24/38).
I know that Specialized is using a similar SRAM dedicated OEM version, and if this would become easily as aftermarket available and would fit the Niner Air AND Niner Air Carbon, that would be awesome and (at least for me) the perfect 29er gearing set up.

Anything know about target availability?
 

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these chainring configs should be available on 2012 product which should start shipping mid-year. Not sure of the exact roll-out for each crank, but figure by Aug. these should be in stock for aftermarket.

Steve
 

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Niner Bikes said:
these chainring configs should be available on 2012 product which should start shipping mid-year. Not sure of the exact roll-out for each crank, but figure by Aug. these should be in stock for aftermarket.

Steve
Steve, can you tell us if they will keep the 120/80 standard for the 38/24 combo or if they will use the 104/64 BCD ?

thanks.
/ktm05
 

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I have installed the XTR Trail 2x10 cranks (24/38) on an Air9 with the new style round stays. Measured with my vernier caliper there is 2.59mm clearance between the 38 ring and the chain stay.

These look ok to me. Any thoughts?

-dan
 

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I think the issue is going to be when shifting to the smaller chainring and from smaller to bigger...

The chain will move outwards a bit and when going to and from, it will most likely dig right into the frame...

I think it is too close, but Steve can verify.
 

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The chain doesn't go anywhere near there.

The clearance of the 38 in middle position is the same as the clearance of the 44 in the outer position.

Also, the XTR race cranks with 28/40 rings is designed as a double. The XTR trail cranks are triple cranks offered with two or three rings.

-dan
 

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darnold said:
The chain doesn't go anywhere near there.

The clearance of the 38 in middle position is the same as the clearance of the 44 in the outer position.

Also, the XTR race cranks with 28/40 rings is designed as a double. The XTR trail cranks are triple cranks offered with two or three rings.

-dan
I was thinking chain suck... Sorry.
 

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I think this is a good amount of clearance and I don't think the chainstays will flex over that much, but chain suck is an issue (maybe use the K-Edge anti chainsuck devise). We do have tolerances called out on our chainstays, and these are on the narrow side of the tolerance, which makes it okay to use this combo for this bike. If there's another Air 9 out there where the chainstays are on the outer limit of the tolerance call out, these would be too close. That's why we generally say that these XTR cranks are not compatible. In this case though, without dealing with chainsuck, these should be okay.

Steve
Niner Bikes
 

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I am looking at buying an older version (not sure what year) of the Air 9 with the diamond-shaped rear chainstays from a friend. I am going to be putting a Sram XX 2x10 (28/42) Q-factor 156 crankset on. From what I've read from a little on here and other posts this will not work correct??? Can somebody let me know yes or no? Will it work with the new 2011 Air 9 frames? I need to figure this out quick so I can make a decision on what to buy as my other race frame (Gary Fisher) is cracked and done and I have some other races coming soon. Thanks in advance!
 

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trz42 said:
I am looking at buying an older version (not sure what year) of the Air 9 with the diamond-shaped rear chainstays from a friend. I am going to be putting a Sram XX 2x10 (28/42) Q-factor 156 crankset on. From what I've read from a little on here and other posts this will not work correct??? Can somebody let me know yes or no? Will it work with the new 2011 Air 9 frames? I need to figure this out quick so I can make a decision on what to buy as my other race frame (Gary Fisher) is cracked and done and I have some other races coming soon. Thanks in advance!
Why would you put a 28/42 on a 29er? that is like a 32/46 on 26er, do you live in flat lands or have the legs of a T-rex?

here is a thread that says the 42t xx is to tight of a clearance to work

with my diamond stays I have just enough clearance with my xtr cranks with an extra 1.5mm spacer on the drive side with a 36t ring. honestly I find that 24/36t is perfect for racing, I haven't been in a race or on a ride yet where the speeds were so great that a 36t (40t 26er equivalent) can't keep up.
 

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I did a quick search on the interweb and found this on both bike198.com & PinkBike.com regarding the 2012 Shimano Deore XT 2X10 cranksets:

"A trail oriented 2X10 crank debuts with a 38-26T ring set as well as a more XC oriented 40-28T combo. Both double cranks feature a unique crank with a 48.8mm chainline for better frame clearance and best compatibility on a wide range of bikes."

mountain.bike198.com/2012-shimano-deore-xt

Sorry, the forum won't allow me to post the link to pinkbike.com since I don't have enough posts.

This is in line with the 48.8mm chainline that's currently spec'd on the XTR 28/40 crankset. It looks like this was Shimano marketing as the quotes are identical. Hopefully this is the case, as I have just ordered a MCR with the 2012 Deore XT 26/38 crankset.
 

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Follow-up

Can anyone say definitively that a Shimano M785 XT 26-38 crank can be used on a Air 9 carbon frame? I have the threaded CYA insert in the frame.

Mine was shipped with Sram x9 GXP 28-42 and want to switch to the above crankset.
Johnny Rocketz post suggest but I was hoping someone could post some more definitive info.

thanks
 

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Can anyone say definitively that a Shimano M785 XT 26-38 crank can be used on a Air 9 carbon frame? I have the threaded CYA insert in the frame.

Mine was shipped with Sram x9 GXP 28-42 and want to switch to the above crankset.
Johnny Rocketz post suggest but I was hoping someone could post some more definitive info.

thanks
From the Shimano Service & Installation documentation on the 2011 XTR and 2012 Deore XT front drivetrains, these are the listed chain line specs:

2011 Shimano XTR FC-M980 (38-26T): 46.8mm
2011 Shimano XTR FC-M985 (40-28T): 48.8mm
2011 Shimano XTR FC-M985 (42-30T): 48.8mm
2011 Shimano XTR FC-M985 (44-30T): 48.8mm
2012 Shimano Deore XT FC-M785 (38-26T): 48.8mm
2012 Shimano Deore XT FC-M785 (40-28T): 48.8mm

Here are the links to the Shimano product documentation:
techdocs.shimano.com/media/techdocs/content/cycle/SI/XTR/SI_5M80A/SI-5M80A-002-00-ENG_v1_m56577569830726445.PDF
techdocs.shimano.com/media/techdocs/content/cycle/SI/Deore-XT/SI_5MZ0A/SI-5MZ0A-001-00-Eng_v1_m56577569830746328.pdf

I also e-mailed Niner about the 2012 Deore XT 2x10 crank compatability, and this was their response:

"Theoretically you shouldn't have any issues with the new crank. I can't however confirm that with certainty having not set up one of those bikes yet. But if the new standard is inline with the (XTR) 40/28 chain line of 48.8 there should not be any issues."

From that statement, I think it's safe to assume that so long as the chain line of the crank is 48.8mm, then the crank is compatible with the Niner A9C frame. From the list above, the only crank that does not have a 48.8mm chain line is the Shimano XTR FC-M980 (38-26T). I'm not sure why Niner has yet to install and test the 2012 Deore XT mech on any of their frames. I wonder if it's a sign that a change to SRAM is coming.
 

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You rock

Awesome info. Truly appreciate it!:thumbsup:
From the Shimano Service & Installation documentation on the 2011 XTR and 2012 Deore XT front drivetrains, these are the listed chain line specs:

2011 Shimano XTR FC-M980 (38-26T): 46.8mm
2011 Shimano XTR FC-M985 (40-28T): 48.8mm
2011 Shimano XTR FC-M985 (42-30T): 48.8mm
2011 Shimano XTR FC-M985 (44-30T): 48.8mm
2012 Shimano Deore XT FC-M785 (38-26T): 48.8mm
2012 Shimano Deore XT FC-M785 (40-28T): 48.8mm

Here are the links to the Shimano product documentation:
techdocs.shimano.com/media/techdocs/content/cycle/SI/XTR/SI_5M80A/SI-5M80A-002-00-ENG_v1_m56577569830726445.PDF
techdocs.shimano.com/media/techdocs/content/cycle/SI/Deore-XT/SI_5MZ0A/SI-5MZ0A-001-00-Eng_v1_m56577569830746328.pdf

I also e-mailed Niner about the 2012 Deore XT 2x10 crank compatability, and this was their response:

"Theoretically you shouldn't have any issues with the new crank. I can't however confirm that with certainty having not set up one of those bikes yet. But if the new standard is inline with the (XTR) 40/28 chain line of 48.8 there should not be any issues."

From that statement, I think it's safe to assume that so long as the chain line of the crank is 48.8mm, then the crank is compatible with the Niner A9C frame. From the list above, the only crank that does not have a 48.8mm chain line is the Shimano XTR FC-M980 (38-26T). I'm not sure why Niner has yet to install and test the 2012 Deore XT mech on any of their frames. I wonder if it's a sign that a change to SRAM is coming.
 

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Cabbgage,

No, it won't fit. The new 2x10 XTR gruppo has a crankset with a 38t outer ring, however this crankset is based on their 3x XTR front crank, so the 2 chainrings are set in the small and middle chainring respectively. This is probably the same as what you're looking at and it's a no go. The 38 is too big to be mounted in the position of a middle chainring. The cranks designed around 2x gearing have a slightly different spacing, and therefor fit fine (SRAM will be making this chainring config for their 2x10 cranks from X7-X0 and it will work fine).

Steve
Niner Bikes
I have set up an Air 9 Carbon with the XTR trail 980 in a 38x26. The 38 is pretty tight, has anyone ever added an additional spacer to the crankset on the driveside to push it out just a little more.

Niner does say a 38 XTR in the front will work with the Air 9 Carbon
 

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I have set up an Air 9 Carbon with the XTR trail 980 in a 38x26. The 38 is pretty tight, has anyone ever added an additional spacer to the crankset on the driveside to push it out just a little more.

Niner does say a 38 XTR in the front will work with the Air 9 Carbon
 
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