parts required for 2x10/gear ratios

andrewyzfr6

im putting xtr 2x 10 on my 5. Its currently running a 22/32/42 up front and an 11-32 on the rear. What sprokets should i fit? I currently use the lowest gears(the top half of the cassette with the 22) and all of the cassette with the 32/middle ring. How do i calculate the gear ratios,i used to know how to years ago, but with the mists of time its been forgotten!!!!

cooldad

Doubt you'll have that much of a choice. Have you looked at the options.
Expensive upgrade though once you've bought new mech and shifters

andrewyzfr6

Well, i need a chain, cassette and chain rings anyway. Plus i dont really use the outer ring(ive been watching for the last few months!) Plus ive damaged my rear mech. And I was hopeing there would be deals on 2011 kit.
On heavy landings my chain has been known to come off, and i see there is a few good chain guides on the market now to work with twin and bash set ups.
anyone know how to calculate gear ratios?! please.....

njee20

If you use the absolute lowest gears then you'll have to go for no higher than a 24t inner ring (with an 11-36 cassette) or you'll lose the lowest ratio.

You could go for 24/36 or something with an 11-36, but not in XTR. The lowest you could go then is 26/38, which will lose you the very bottom gear as you have now.

There's a calculator on Sheldon Brown where you input sprocket sizes and it'll tell you roll out, speed at a cadence etc. However they are just simple ratios - just divide cassette sprocket by chainring to tell the extremes. 22/34 < 26/36

composite

I was under the impression that you can't go above 36 tooth on the middle ring on a Five because it fouls on the pivot. Is that right?

Kaise

you dont need to change your front mech or your rear mech (as long as they were trunning 3x9 previously.

i have kept my sram x-0 kit and gone 2x10 and just adjusted the limit screws to allow for the larger range on the rear and and tighter range on the front. You will need new shifters as the indexing will be wrong on the rear. When the front mech is constrained by the limit screws the shifter wont know any different.

i am waiting for someone to till me am wrong now, and i can tell them to jolly over to bristol and have a look at the bike thats been ridden a fair bit in the past few weeks with this very set up.

andrewyzfr6

Hi thanx for the help! I've ordered shifters and a rear mech. Just going to calculate rails to order chain rings and cassette. I'll see what happens about a ft mech and chain device.
I take it the cranks have no problems running two chainrings instead of 3?! And a chain device?

anjs

yes you do for shimano kit as the pul ratios are different

cooldad

kaiser83 wrote:

i am waiting for someone to till me am wrong now

You are wrong. Shimano 9 speed mechs will not work with 10 speed shifters.

Frodo1095

This is the link to Sheldons page which I found really handy:
http://www.sheldonbrown.com/gears/

This is my 2x10 set up.
SRAM 2x10 26/39 on 12/13/15/17/19/21/24/28/32/36 with 175mm crank
84.3
77.8
67.4
59.5
56.2
53.2
51.9
48.2
45.0
42.2
39.7
36.1
35.5
32.1
31.6
28.1
28.1
24.1
21.1
18.7

dusk

cooldad wrote:

kaiser83 wrote:

i am waiting for someone to till me am wrong now

You are wrong. Shimano 9 speed mechs will not work with 10 speed shifters.

can you elaborate please, i'm looking at going 10 speed and was wondering about compatibility

Dirtydog11

Is my 2011 frame compatible with M980 and M985 XTR cranks?

The 10-speed Shimano XTR crank has now been split between two categories, the ‘race’ oriented M985 and the ‘trail’ dedicated M980.

The ‘race’ inspired 2x10 specific M985 option is built for the race purists who want the lightest possible build, with a close gear ratio ring combination for a smaller but more dedicated range. The decreased cadence change between shifting maintains momentum, with the narrower Q-factor having apparent efficiency advantages, but compatibility issues with most frames.

The ‘trail’ inspired M980 is designed for more all condition use, with wider gear ratios and broader functionality being the mainstay of design. Increased rigidity, durability and reliability with little weight compromise over the ‘race’ version. The M980 is also interchangeable between two and three rings depending on model.

Five

The Five SE is fitted with the FC-M980 and 42-32-24 ring combination. This provides ample frame clearance and the broadest shift combination for all-mountain and trail applications.

The 38/26 version of the FC-M980 is NOT compatible with the Five frame, neither is the FC-M985 range, all having ring clearance issues with the main pivot.

supersonic

Ten speed shifters must be used with the same brand of ten speed rear mech.

njee20

The M985 Race cranks have bigger rings, rather than a closer range. They also have a unique 88mm BCD, so you can't get other off the shelf rings.

cooldad

dusk wrote:

cooldad wrote:

kaiser83 wrote:

i am waiting for someone to till me am wrong now

You are wrong. Shimano 9 speed mechs will not work with 10 speed shifters.

can you elaborate please, i'm looking at going 10 speed and was wondering about compatibility

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