# What derailleur length for 1x10



## kikoraa (Jul 25, 2011)

I have a 2012 giant trance x and want to go 1x10. I will probably use 32t up front with 11-36 in rear. Should I stick with medium or could a short cage work?


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## 29Again (Mar 27, 2005)

I can't see the stickies when using Tapatalk, but I recall this one:
http://forums.mtbr.com/drivetrain-s...ong-cage-vs-short-cage-derailleur-284688.html

It is always good to get another forum's opinion and flavor on a topic. Perhaps this forum has more mechanics and fewer Fred's like me.

As I understand, if you don't want to buy a new RD, then what you are using on the bike will work presuming it is 10-spd.

If you want the benefits of a shorter RD, then a short cage SRAM or GS (Medium) Shimano will work fine. Shimano doesn't make a "mountain bike short cage" any more. Since you are going 10-spd, using a Shimano short cage road RD is no good, but that is another can of off topic worms.

Your particular equation is:
0 + (36T-11T) = 25T
This is well under the SRAM Short cage or Shimano GS capacity.

You will of course more than likely need to take countermeasures to keep the chain solidly on the front chainring with a chain guide of some type/form. But that is mostly independent of your RD cage.


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## kikoraa (Jul 25, 2011)

I will be buying a new RD. I bought the base model trance and it has 9 spd deore. I also have a bashguard and a jumpstop laying around but I may pick up an mrp down the road. I used a long cage for a 1x9 once and it was fine. I just figure a med or short would be more efficient and quicker. I don't care if its sram or shimano. Ive used both high ends and enjoy both. I'll just gather some dough and wait out for a good deal. Thanks it the help. I thought since ill be using 36t max I may need medium. How did you get that equation?


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## 29Again (Mar 27, 2005)

For the equation, check that link I gave.


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## Rippingdale (Jun 22, 2009)

I have three 1x9 setups. Ring diameters should be the same even though you’re considering a 1x10. I used a short cage on two of my builds with the following sizes.

Saint short cage, 32t front, 11-34 rear, bash ring, no inner ring or inside chain-stop, chain does not drop.

X0 short cage, 32t front, 11-34 rear, bash ring, no inner ring or inside chain-stop, chain does not drop.

XT long cage, 32t front, 11-34 rear, bash ring, inner ring (1/16" alloy ring), chain does not drop with the inner ring. The long cage did not provide enough chain tension to prevent drop. The inner ring solved the problem. I can supply a photo if interested.

Also, I recall 34t being the maximum rear gear size for most short cage MTB derailleurs.


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## kikoraa (Jul 25, 2011)

I will be using an 11-36 cassette. If 34 is max for short then ill go with med. I hate long cage derailleurs. They just seem clumsy and I've destroyed a few while riding.


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## RED5 (Jan 4, 2004)

For any 1x application, no matter what size ring or cassette short cage is best choice and always works.


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## kikoraa (Jul 25, 2011)

Awesome. Thinking about it I may go with med for future 2x10 use when I move to rougher terrain.


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## Rippingdale (Jun 22, 2009)

RED5 said:


> For any 1x application, no matter what size ring or cassette short cage is best choice and always works.


Shimano saint short cage will not work with 36t. Nor will SRAM's XX downhill. The other SRAM short derailleurs may work.


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## Guy.Ford (Oct 28, 2009)

Rippingdale said:


> Shimano saint short cage will not work with 36t. Nor will SRAM's XX downhill. The other SRAM short derailleurs may work.


I assume you mean cassette, not ring. As long as your using a 9/10sp cassette with 9/10sp der it will work. :thumbsup:

There is no max wrap for running single ring. There is a formula somewhere that shows the science but frankly Im too lazy to search for it.


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## Rippingdale (Jun 22, 2009)

Guy.Ford said:


> I assume you mean cassette, not ring. As long as your using a 9/10sp cassette with 9/10sp der it will work. :thumbsup:
> 
> There is no max wrap for running single ring. There is a formula somewhere that shows the science but frankly Im too lazy to search for it.


I'm talking about the largest ring on the rear cassette. OP wants to use 36t.in rear (i.e. 11-36). I've never tried using a 11-36 but both manufactures say no-go. 34t max for short saint and 28t max for X0 downhill. See Lnks:

Saint

SRAM X0 DH Rear Derailleur | SRAM

I'm running a 11-34 with short saint. The upper pulley is very close to touching the 34t ring. A 36t will most likely cause interference. Other SRAM derailleurs may work, not sure.


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## Guy.Ford (Oct 28, 2009)

Rippingdale said:


> I'm talking about the largest ring on the rear cassette. OP wants to use 36t.in rear (i.e. 11-36). I've never tried using a 11-36 but both manufactures say no-go. 34t max for short saint and 28t max for X0 downhill. See Lnks:
> 
> Saint
> 
> ...


Hmmm speaking strictly about the Saint, I'd be willing to bet the limit is based off the fact that at the time Saint came out there were no 36t cassettes. Of course this is all conjecture on my part.

However, what I can tell you for a fact is that I'm running an 09 SRAM X9 short cage with a 36t cassette on my bike, without any issues and it clearly states in the following SRAM tech manual http://www.sram.com/sites/default/files/techdocs/my10-sram-tech-manual-rev-a.pdf that max sprocket is 34t. :thumbsup:

I dont doubt the validity of the SRAM XO DH not working however, seems they took very large steps to keep it a DH only option. But I still say Saint would work - again conjecture.

Edit: FWIW here is the formula for figuring 1x systems...
http://forums.mtbr.com/5776304-post6.html


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## kikoraa (Jul 25, 2011)

So medium it is...


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## samdemo (Oct 25, 2005)

running a 11-36 10spd cogset with a short x9 derailluer....no issues so far.


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## RedBen (Nov 4, 2010)

Both X7 and X9 are listed as working with 36t rear cogs. Since it doesn't mention which length works with 36t, I would assume that short, medium, and long all work.


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## Dispatch (May 16, 2011)

*Does work*

I was asking myself this same question but apparently the new saint does work with 36 in the rear cassette as per their april 2012 press release:Announcing New SAINT M820

_New chain control and silencing technologies in the new RD-M820 are a game changer for gravity riding. In addition to the proven Shadow Plus RD design, a Saint specific, high durometer urethane bump stopper (between the RD and the dropout) was added to reduce impact noise. Now 10-speed, the new RD-M820 features a durable super wide link that serves as the backbone of the DH parallelogram. Ready for track and trail, the mode converter easily adapts between two settings for MTB cassette gear ratios (11-32, 11-34, 11-36) and road (11-23, 11-25, 11-28)._


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