XTR di2 M8050 vs Ultegra R8050 RD for CX/Gravel

[raggi]

Title says it all really.

Going to be putting together a gravel grinding/winter bike with a 1x di2 setup for the coming fall/winter. I'll probably race CX on it, but more as a workout rather than competitively. Then it'll be used as a winter training bike, commuter and gravel grinder.

Should I go for an M8050 rear derailleur (clutch, more range (probably not needed?)) vs the new Ultegra R8050 rear derailleur (lighter, less expensive)?

I'll be using the R8070 shift levers+brakes and a single 40T chainring in the front (haven't decided on which).

[hmai18]

Just get the clutch. If you're using it for gravel grinds/winter duty, I wouldn't really care that much for the extra few grams to get the benefit of a clutch and the ability to throw an 11-42 on the back.

You always think you don't need the range until you're on grades in the double digits and you've run out of gear.

[cdncyclist]

I had this same question (for cx only though), and came to the conclusion that there probably isn't a 'best' answer.

Both will allow you to get to 32 teeth (which is the max I was thinking - as noted above if you think you need more, go with XTR).
You mentioned the weight / cost
I have heard there may be issues with friction with a clutch, but from what I hear this sounds like it is probably trivial
Then finally there is keeping the chain on with lots of options:
- narrow wide
- chain catcher / keeper
- clutch

FWIW I went with ultegra, narrow/wide, and a chain keeper, but after polling many there was no clear consensus.

[wheelsONfire]

Do you know if the XTR RD will work with the new shifters?
I heard the R785 worked with the XTR RD, but if the all new is compatible, i don't know!?

Back when my UP was built (begining of 2016) i called Shimano and asked about mixing components from different groupsets, that was not liked at all.
It seemed they were hellbent on us not cross-mixing road and mtb components.
They void all sorts of warranties if we do.
I asked about using mtb calipers in conjunction with R785 shifters and that was same, void all warranty.

But for 1*11 i would also look at a wider range cassette.
Or use 11-34 cassette and TA Specilaties 44/33 chainrings.

I run 6870 GS + Wolf tooth Roadlink. This to make the RD handle Sram PG-1170, 11-36 cassette.
I also run 44/33 chainrings at my 6800 crank.
This gives me a fair range to ride tarmac, fast gravel and even mtb tracks.

Check here:
https://specialites-ta.com/plateaux/roa ... nring.html

You can run even 42T large and down to 33T small.

Here is the plastic bits needed (for Ultegra 6800 crank, 9000 crank is another option)
https://specialites-ta.com/accessoires/ ... aches.html

[hmai18]

The warranty thing is BS when you consider that the current SuperX is factory spec'd with R785 levers and an M8050 RD:
http://www.cannondale.com/en/Canada/Bik ... =undefined.

[dmcgoy]

Title says it all really.

Going to be putting together a gravel grinding/winter bike with a 1x di2 setup for the coming fall/winter. I'll probably race CX on it, but more as a workout rather than competitively. Then it'll be used as a winter training bike, commuter and gravel grinder.

Should I go for an M8050 rear derailleur (clutch, more range (probably not needed?)) vs the new Ultegra R8050 rear derailleur (lighter, less expensive)?

I'll be using the R8070 shift levers+brakes and a single 40T chainring in the front (haven't decided on which).

I'm doing the same. R8070 + XT Di2 + 11-34 (9/10 speed hub). CX and commute bike. My commute has a 2 mile gravel stretch with tons of ruts that I'm hitting at nearly 20mph. So, lots of chain slap. I'm pretty excited at the idea of a quiet chain with a clutch derailleur.

I'm mostly annoyed that the R8070 is nowhere to be seen.

[FIJIGabe]

Since you're going 1x, there's really no option: you have to go with the XT RD. Ultegra requires you to use a FD/RD combination. My understanding is that the RD won't work w/o the FD plugged in. Any etube shifter will work with any etube derailleur, so you can use 6700/6800/8000 shifters with XTM8050 with no problem.

[raggi]

Since you're going 1x, there's really no option: you have to go with the XT RD. Ultegra requires you to use a FD/RD combination. My understanding is that the RD won't work w/o the FD plugged in. Any etube shifter will work with any etube derailleur, so you can use 6700/6800/8000 shifters with XTM8050 with no problem.

That can't really be true.. see this for example. Also, when I was setting up the 6870 on my road bike I had only the RD connected (and vice versa) while testing it out and it worked fine.

With regards to mixing MTB and road components, from what I've read it seems to be A-Ok as long as you don't use a MTB RD and road FD (or the other way around). Shifters and derailleurs can be mixed just fine.

Thanks for the input guys! I think I'm gonna go with the XTR RD to get the clutch, and I might end up using this bike to climb over some pretty hefty mountains for the fun of it, which I don't really fancy tackling with 40-34 as my biggest gear.

[dmcgoy]

Since you're going 1x, there's really no option: you have to go with the XT RD. Ultegra requires you to use a FD/RD combination. My understanding is that the RD won't work w/o the FD plugged in. Any etube shifter will work with any etube derailleur, so you can use 6700/6800/8000 shifters with XTM8050 with no problem.

That can't really be true.. see this for example. Also, when I was setting up the 6870 on my road bike I had only the RD connected (and vice versa) while testing it out and it worked fine.

With regards to mixing MTB and road components, from what I've read it seems to be A-Ok as long as you don't use a MTB RD and road FD (or the other way around). Shifters and derailleurs can be mixed just fine.

Thanks for the input guys! I think I'm gonna go with the XTR RD to get the clutch, and I might end up using this bike to climb over some pretty hefty mountains for the fun of it, which I don't really fancy tackling with 40-34 as my biggest gear.

The only concern I have is that Shimano will update the firmware to disallow mixing Road/MTB parts. It USED to be possible to have mixed road/mtb derailleurs...then Shimano updated the firmware.

[FIJIGabe]

Since you're going 1x, there's really no option: you have to go with the XT RD. Ultegra requires you to use a FD/RD combination. My understanding is that the RD won't work w/o the FD plugged in. Any etube shifter will work with any etube derailleur, so you can use 6700/6800/8000 shifters with XTM8050 with no problem.

That can't really be true.. see this for example. Also, when I was setting up the 6870 on my road bike I had only the RD connected (and vice versa) while testing it out and it worked fine.

With regards to mixing MTB and road components, from what I've read it seems to be A-Ok as long as you don't use a MTB RD and road FD (or the other way around). Shifters and derailleurs can be mixed just fine.

Thanks for the input guys! I think I'm gonna go with the XTR RD to get the clutch, and I might end up using this bike to climb over some pretty hefty mountains for the fun of it, which I don't really fancy tackling with 40-34 as my biggest gear.

The only concern I have is that Shimano will update the firmware to disallow mixing Road/MTB parts. It USED to be possible to have mixed road/mtb derailleurs...then Shimano updated the firmware.

Don't update the firmware, and you'll be fine

Regarding the Ultegra FD/RD, if you plug it into the etube software, I'll venture a guess that a trouble code is being thrown for missing FD. I guess it works, but that wasn't my understanding. Either way, you are correct, you can mix any type of shifter, but you can't mix derailleurs.

[wheelsONfire]

The warranty thing is BS when you consider that the current SuperX is factory spec'd with R785 levers and an M8050 RD:
http://www.cannondale.com/en/Canada/Bik ... =undefined.

That's cool, but this is what i was told talking to Shimano Nordic and a german shimano center.

[Nefarious86]

How are they going to know what other components you used?

[wheelsONfire]

How are they going to know what other components you used?

Is this question for me?

If so, i have had issues with batteries draining very quick.
I have had two batteries exchanged so i am on my third now.
I also carry a spare all the time.

Shimano can actually have the bike shipped over to them and check it out.
That is if a Shimano center can't solve the issue.
This could lead to changing components which is covered by warranty.
If you cross-mix and the say NO, you're own you own.
If you others don't care, fine by me!
But if it happens again and again and you can't rely on the bike it's really worth having warranty and help.
Also, if fails do happen quite often a suggestion is to check all connectors and update firmware.

Electronic groupsets may suffer some issues old school wired simply won't.

However, i admit it's a bit weird that both German shimano center and ours says it's like this.
A guy just showed a Cannondale bike is factory built with XT RD and R785 shifter.
So i must admit this is a bit strange.

I ordered my bike as a custom build. I actually considered trying 1*11.
So i asked about using XTR RD. But the dealer refused to build like this.
This was due to the fact Shimano deny all warranty or anything really if we do this.

Anyway, a nice example is me just asking about using XTR 9000 calipers with R785 shifters.
Even this is a not liked by the Shimano centers or Shimano Germany or Shimano Nordic.

[raggi]

A guy just showed a Cannondale bike is factory built with XT RD and R785 shifter.

Same with the 2018 S-Works Diverge, comes with the XTR M9050 di2 rear derailleur and R785 levers.

Surely someone at Shimano would have caught onto two big manufacturers providing this as build specs and pulled some strings?

[motorapido]

There a a fair few bike builds, including factory sponsored riders mixing up XT or XTR Di2 with Road Di2. so Shimano are obviously aware of it. in fact I remember one shop build monster Cross Santa Cruz Stigmata build in the UK where they got a Shimano UK tech to set it all up.

link found http://www.sprocketscycles.com/blog/stigmata/

Not sure why the Shop mentioned by wheelsONfire would be so scared of warranty issues. its not like you would send the whole Di2 setup back if a component didn't work, its surprising what will work together. Most of my builds would be a shop warranty nightmare but i'm willing to risk it to get the setup i want. I have built and use the following mashups.

Scott Scale 29er MTB 1x10 11-42 cassette, Alfine shifter operating an Ultegra 6770 rear mech which has a modified B knuckle to take a clutch to with an XT M8000 cage and Road link. and have been running the rear mech originally with a One Up Rad cage since before there was an XTR Di2.

MY CX bike is a Niner BSB, i did run the same mech setup as above on an earlier build with a RAdr cage,

but now run an XT Di2 mech with Goatlink and just the brain from a Di2 climbing shifter operated by momentary switches,
just to mix it up a bit more, the momentary switches are in Sram hydro brakes and operated by the Doubletap lever paddles RH up LH down.

Road bikes are both 6870 2 x 11 Di2 one with the electronics in Sram HydroR rim brake lever bodies with the the Ultegra Di2 lever modified to operate the hydro piston inside the Sram lever body, Second bike is the same setup but runs discs. both also have Custom Sprint and climbing shifters, and have been no issues with setup or running them.

Anything is possible, but your warranty might be voided.