XT di2 rear derailleur Cassette Options

[velobob]

I am thinking of replacing an Ultegra Di2 short cage rear der with an XT Di2 medium cage on my giant tcx advanced 1 cross bike. I have RS785 hydraulic shifters. The goal is twofold - first to increase the size of the cassette to 11-32 (the max I can run now is 11-28) and second to get the clutch system.

I believe the shifters are compatible but the question I have is - can I run 11-32 road cassettes or would I have to run 11-40 or 11-42 mtn bike cassettes? I've read conflicting things on this. I have noticed however that the new Cannondale SuperX top model is spec'd with the XT Di2 rear derailleur and an 11-32 105 cassette so I think I should be fine.

Any insights much appreciated!

[boots2000]

Shifters are compatible, but in my experience the mtb derailleur plays better with the 11-40 or 11-42.

[ooo]

xt di2 can do 11-28
ultegra ss can do 11-32
for 1x ... clutch is 2 step forward, but longer cage (gs vs ss) is one step back

[velobob]

xt di2 can do 11-28
ultegra ss can do 11-32
for 1x ... clutch is 2 step forward, but longer cage (gs vs ss) is one step back

why is longer cage one step back?

[Bhaalgorn]

I'm running RS785 brifters + 11-28 cassette + long-cage XTR Di2 derailleur in 1x right now with no problems. I also run with 11-32 and 11-36.

[velobob]

I'm running RS785 brifters + 11-28 cassette + long-cage XTR Di2 derailleur in 1x right now with no problems. I also run with 11-32 and 11-36.

this is good to know - thx!

[hurricanejosh]

the shimano 11 speed road & MTB chains and cassettes use the same spacing. the difference is how it sits on the freehub body. XT and XTR cassettes will fit on 10 speed road wheels, where 11 speed 105/ultegra/duraace cassettes require a wider 11 speed freehub body.

[velobob]

I'm running RS785 brifters + 11-28 cassette + long-cage XTR Di2 derailleur in 1x right now with no problems. I also run with 11-32 and 11-36.

what kind of cassette is the 11-36?

[wheelsONfire]

I'm running RS785 brifters + 11-28 cassette + long-cage XTR Di2 derailleur in 1x right now with no problems. I also run with 11-32 and 11-36.

what kind of cassette is the 11-36?

You can use Sram PG-1170, 11-36.
I do with 6870, 6870 RD medium cage + Wolf tooth Roadlink.
But i run 2*11 if it matters.

[Bhaalgorn]

I'm running RS785 brifters + 11-28 cassette + long-cage XTR Di2 derailleur in 1x right now with no problems. I also run with 11-32 and 11-36.

what kind of cassette is the 11-36?

I don't think it matters.

11-28 is an Ultegra. 11-32 is a PG1170. 11-36 is PG1140. All with SRAM PG1170 and KMC X11SL chains.

[DutchMountains]

I'm using 14-32 (combination of Ultegra 14-28 junior cassette and 11-31) with XT Di2 and RS785 shifters. Works fine. Front rings are 34/42.

The only thing is that syncro shift doesn't work with the XT Di2 when you have the regular road junction, you MUST have the SC-MT800

[ultimobici]

Are you planning on ditching the front mech? If so it is compatible. If not it will not work as the system can only function with both mechs being MTB or both being Road. If you want to use an 11-32, why not just swap out the mech for a 6870GS mech?

[wheelsONfire]

I'm running RS785 brifters + 11-28 cassette + long-cage XTR Di2 derailleur in 1x right now with no problems. I also run with 11-32 and 11-36.

what kind of cassette is the 11-36?

I don't think it matters.

11-28 is an Ultegra. 11-32 is a PG1170. 11-36 is PG1140. All with SRAM PG1170 and KMC X11SL chains.

That is not correct.

I have two PG-1170, 11-36.
https://www.sram.com/sram/road/products ... 13fys5wzrw

As mentioned, you easily use these with 6870 GS (medium cage) + Wolf tooth Roadlink.
https://www.wolftoothcomponents.com/products/roadlink

On top of that, you can run TA Specialities 44T or even 42T large chainring and 33T small chainring.

I run Shimano CN-HG901 chain.

[Bhaalgorn]

I'm running RS785 brifters + 11-28 cassette + long-cage XTR Di2 derailleur in 1x right now with no problems. I also run with 11-32 and 11-36.

what kind of cassette is the 11-36?

I don't think it matters.

11-28 is an Ultegra. 11-32 is a PG1170. 11-36 is PG1140. All with SRAM PG1170 and KMC X11SL chains.

That is not correct.

What isn't correct? The brand of the cassette doesn't matter.

[wheelsONfire]

PG-1170 is for sure 11-36 as proven by the link.
Or did you mean what you yourself use?
If so, my mistake. I thought you ment PG-1170 is not available as 11-36, only PG-1140,