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Hi
Ordered a medium cage XTR M9000 11 speed derailleur to go on my XTR 11-40 cassette and my m9020-2 hollowtech2 26-36 crankset, will i need a long cage for that configuration? gearing will be 2x11 on my setup.
You're a couple of teeth over the capacity of the GS/med derailleur (37, I believe), so unless you're really careful not to crossring max to max, which w a 2x should be possible either by race or accident- change to a long cage and never worry.
 

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thanks,
glad i asked before my return policy expires.

You're a couple of teeth over the capacity of the GS/med derailleur (37, I believe), so unless you're really careful not to crossring max to max, which w a 2x should be possible either by race or accident- change to a long cage and never worry.
 

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I will be running 2x9: 36/22 front and 34/11 rear.

Total chain capacity / chain wrap = 37

Is my math correct?

Should I be getting a medium SRAM or long Shimano cage?

Will the medium cage shift faster, in this case SRAM will be better?

Thanks!
 

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I will be running 2x9: 36/22 front and 34/11 rear.
Total chain capacity / chain wrap = 37
Is my math correct?
Should I be getting a medium SRAM or long Shimano cage?
Will the medium cage shift faster, in this case SRAM will be better?
Thanks!
Your shifter will have to match your derailleur brand -they have different cable pull ratios (for the rear).
A med does not shift faster than a long.
Math is correct but...
I have always been able to fudge a med Shimano past capacity by a couple of teeth.
I personally have a Shimano preference; I've found the springs on Sram (lower end especially) derailleurs to be a bit weak, thus shifting more finicky over time.

I will go check a couple of my older (still) 9speed 2x bikes and see how far I have been able to overshoot w success. Until then, when in doubt, go long.
 

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I ordered an SRAM Attack Twist Shifter 9 speed RD shifter to use with a Shimano Acera 9 speed RD. I will also get an SRAM X9 microshift for the front Acera RD (2x10 crankset). That way I can keep using Shimano RD/FD.

I'm looking into upgrading the RD mech. Considering a used long cage Shimano XTR RD-952. Good or bad idea?
 

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Hmmm....

Different "long" & "medium" derailleurs from different model-change years, or epochs really (Shimano / mountain), are not always the same, speaking of the 952. And you do not know the history o' that used XTR. Nice derailleur and all, I have a couple in the bin that will go on older bikes for sure.
But $55 gets you a new Shadow M772 9 speed long cage though (strong spring), and w new Sram Attacks 2:1, you are guaranteed as crisp shifting possible for such a combination -and that's a pleasure. You will be able to concentrate on riding more.

Poor shifting is like a disease, it can creep up on you. You put up w it for a while, making further accommodations i.e. slight overshifts for slop etc... Instead plunk down for new, longer shifting "life".
 

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You have a good and valid point about that. I'm just so tired of our environment piling in heaps of throw away items instead of rebuilding or restoring products. Pet peeve. :)
 

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You have a good and valid point about that. I'm just so tired of our environment piling in heaps of throw away items instead of rebuilding or restoring products. Pet peeve. :)
I can definitely respect that ethic.
But since you are overhauling the whole drivetrain, spend what is relatively very little -especially now- on that Shadow M772. The rear derail is a hardworking, complicated part, and an important place to start new & fresh, truly.
 

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I'm about to order the M772 as you suggested. Jenson says to get medium because it's double front with 36/22 and 34/11 .. agree or disagree?

Shimano XT RD-M772 9SPD Rear Derailleur > Components > Drivetrain > Mountain Rear Derailleurs | Jenson USA
I always assume w a double, I am fine w a GS. I run my newer shadow plus on my 10sp w 35 capacity w actual 37 existing (11x36, 26/38), and I can't afford more overshoot really.

Your 9sp Shadow GS has specs of 33 to 35 depending on where you read it (Shimano says 33 on spec sheet for the M772)
So, reasonably go over a couple of teeth, but if it is really 33, and your 37, you're too short. Call Jenson back and give them the figures. Answer back here for narrative/informative sake, thanks.
 

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If this was for a raucous MTB, downhill et al, I would say GS (but then safe assumption a dual suspension, then might worry about chain-growth between front and rear depending on design, so on and so on...)

But for your hardtail, less-antic riding style, less worry if big/big, less stress on upper spring arm, SGS is the way to go!
 

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After reading all this, I'm wanting to clarify. I have a nice 2x10 setup I've been using with a saint shifter pod and an m780-SGS XT rear mech. It's shadow but not shadow "plus" with the extra tension and stuff. Now I really want to drop the front derailleur and switch to 1x10 with a Sunrace 11-40 1x10 cassette.

The thing that worries me is that I'll probably be using a 28T front cog (I live among high mountains and I really need the bottom end more than the top)

Do I need to worry about chain slap or having chainline problems with this setup? From reading all this, I grok that GS might be optimal. Should I plan on using a chainguide since my rear mech is only Shadow and not Shadow + and it's also SGS? Or can I proceed and not anticipate any problems?

Thanks. [:)
 

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real life question..

Without any theoretical explanations.. can a shimano GS (not the new 8000 model.. older ones) with a shimano rated capacity of 35T work with a 39T combo?

I found all different explanations.. yes... no... wont work in cross gears...

I need real life application (talking STRICTLY about HT bikes).. can a man use GS RD for a 39T combo and drive around without sitting on a dissaster waiting to happen?? I know that SGS is a proper way to go, but I know there are people runing GS on 39T.. so .. people... enlighten me. I got into a discussion (theoretical mostly) without real life ridfing to back it up.... One guy broke a chain, although don't know how to relate the capacity with chain breaking...if it shifted normally up to the breaking point...
 

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I just got my package of new M8000 1x11 group today for my Fatboy
and think I may have ordered the wrong deraileur..

The cassette is the 11-46t 11 speed and I thought I needed the M8000 GS deraileur but I'm afraid it won't hit that last 46t cog, am I okay or do I need to exchange for the SGS. Probably should have asked before I ordered :/


Sent from my SM-N920V using Tapatalk
 

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The GS cage is the right cage for 1x, the SGS cage is for 2x and 3x.
The size of the cage has nothing to do with the biggest sprocket it can clear.
And the M8000 can clear sprockets up to 46 teeth. You have to put a chain in there and adjust the B-screw.
 
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