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Discussion Starter · #1 ·
I've got a 2011 jamis xcr team 26r with a shimano xtr m985 2x10 drive train. I'm really struggling with the lack of a granny gear for tough technical climbs. The stock gearing is 28/40 on the front and 11-36 on the back. I have not been able to find any options for switching out gears except to go even taller. As far as I can tell ( but consider I don't know much!) is that I need to switch to a triple in the front as well as a new front derailer. This seems like a lot of dough just to switch my gearing. Does anyone have any thoughts or other options?
 

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Mantis, Paramount, Campy
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Discussion Starter · #3 ·
Thanks, I think it's a combo of not being very strong and that I like to use a granny gear to rest between obstacles or short bursts up steep sections. I've tried to adjust to the 2x10 but I end up walking up stuff that I previously didnt have to on my old setup.

Anyway, thanks for the links. So I think I'm going to contact wolf tooth and see what would work out. Going from a 36 to a 40 gives me a 10% reduction I think ? 40/36= .9. That might do the trick. Please keep commenting if there are other ideas
 

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NedwannaB
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I've got a 2011 jamis xcr team 26r with a shimano xtr m985 2x10 drive train. I'm really struggling with the lack of a granny gear for tough technical climbs. The stock gearing is 28/40 on the front and 11-36 on the back. I have not been able to find any options for switching out gears except to go even taller. As far as I can tell ( but consider I don't know much!) is that I need to switch to a triple in the front as well as a new front derailer. This seems like a lot of dough just to switch my gearing. Does anyone have any thoughts or other options?
XTR 28/40 is their "race" gearing crank setup. You may be able to get the 26t granny ring (from the 26/38 "trail" set not sure of bcd matching) to work with the original front der tooth spread. If not switch crank sets. You could probably sell and buy an XT 24-26/38t set with leftover, or get someone to trade if they aren't too badly worn.

Or make the mod to your cassette. Not too many doing that setup on a 2x/3x setup tho.
 

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NedwannaB
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FWI, the M960/M970 triple cranks come with a 22T granny ring and you can find them used starting at around a $100..


Note: they are 9speed but so far they work great with 10speeds too..
Awe I miss my 960's. But I think they have a different bcd than the 985's. I know the mid/big are specific to that series. Could be standard on the 22t tho. Not sure.
And again, not sure the 2x derailleur would drop to the 22t and still work on the 40t, and vice verse.
 

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XT cranks use the standard 104/64 BCD. Which means you can go as low as 21T on the granny without modifying the cranks and down to 20 with some filing.

You might have a problem with getting a 40T big ring to play nice with 20/21/22 granny tho. Even if you get the shifting right, the 18-20T gap is kind of unpractical. Thus a switch to a smaller big ring is also advisable. Once again - 104/64 is as standard as it gets.

I make 35/21 rings ( pm me for details ). You can also get quality rings in 36/22 ( the standard setup ) from multitide other vendors ( truvativ, blackspire, praxis works, wickwerks - from the top of my head ).
 

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Hi,

I have a XTR M985 38/26 that was standard on my bike. I found the 26 was a bit big climbing the mountains in the Drakensberg (South Africa). The XT comes out with a 38/24. I replaced the current chain rings with the XT ones. There is a 2-3mm thick spacer that is needed on the smaller chainring to get to offset correct for the M985 crank. Parts Numbers:
Y1ML98040 38T-AM
Y1ML24000 24T-AM

From my investigations 14 is the biggest gap that one can go to, however I want to try a 40T for the large flat terrain that I often ride.

I have a feeling that one only needs to change the 26T to a 24T, but I decided to do both.

I hope this helps.


Gregg
 

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Discussion Starter · #16 ·
After much research, I've read that my m985 2x10 race crank setup will not support anything less than a 28 tooth chainring.

I went ahead and ordered the 42t from wolf tooth. Thanks for all the help and I will report back with results.
 

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I have an XT drivetrain, but I use an X0 triple crankset with the big replaced by a bash ring, so it's 22/33/bash. This gearing allows me to do about 80-90% of my riding in the 33t ring, but I have that nice low granny ring available when I want/need it.
 
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