r8000 rear derailleur not compatible with 6800?
 

I just put on a R8000 ultegra long cage rear derailleur and 11-32 cassette on my 2018 hi mod disc to replace my 6800 RD.

I've tried everything to try and set the alignment correct and yet the alignment is always off. The jockey wheels cannot line up with the cassette correctly.

I've heard the new r8000 sits differently from the 6800

Could I be having compatibility issues ?

Has anyone else ran into this problem ?

I might have to redo the install and this time get a 6800 RD. Before I bought it I read there was no compatibility issue but apparently that is not so

The 8000 is a Shadow Tech RD, so it sticks out less, but according to all of the Shimano compatibility docs, there shouldn't be a problem with any of the 11-speed STI levers.

https://c1.staticflickr.com/1/896/26...ca2a71a3_o.jpg

My rear shift/brake 6800 lever broke a few weeks ago and I had to use the R8000 lever from my new road bike as a temporary workaround. It shifted perfectly for hundreds of miles. I'm pretty sure the all the 11 speed systems are compatible.

For what it's worth I spent a few hours toying with mine and found riding it on the road vs on the stand was far easier for adjustments.

It shouldn't be a compatibility issue. Do you have the high and/or low limit screws too tight or too loose? I would look there first.

I have an R8050GS on my r785 gravel rig. Works fine.

Spent 4 hours today working on the bike.

It works, it was a cable tension issue and the RD was not sitting on the hanger correctly. There are 2 tabs. Shimano manual says to seat the RD on the upper tab but mine needed to be seated on the lower tab. Then everything came into alignment . Before I could not get the jockey wheels to align correctly.

Replaced the cable. Pulled nice and tight, works good.

I went with the RD8000 mainly cause we have roads here where I would enjoy the 11-34.

Now its working, but its near impossible to get the rear wheel off the bike, since the cassette will not clear the rear derailleur and chain, with the disc brake rotors being an issue, also not able to clear the frame. "Shadow tech" ftw but I heard this is also an issue with dura ace RDs.

So, I'll probably just go back to the 6800 and keep a 32. Sad I never got to try the 34 :( .

Apparently the bike shop (REI) that built the bike, who lost my pinch bolt and my cable housing btw, ran the shifter cable below the BB spindle, which is a big no no on this bike, and it was starting to cut through the spindle. And that explain tension issues since cable was not routed correctly and pinched internally. Never take your bikes to unknown mechanics if you're paying for it. I paid for it since I didn't have the time, waste of money, the job was not done right.

Will take it for a spin tomorrow and see how the cable tension holds up.

https://imgur.com/a/ivRG1

Not being able to take the wheel off has to be one of the more odd reasons that I've heard for someone switching a derailleur. Is it really that problematic when you shift to the 11t and try to remove it? Also, I wouldn't be surprised if the 6800 GS would work with a 34t just fine, so if you do go back to the 6800, you might as well give the 34t a whirl.

Yes. It's very difficult but I'm going to try to see how to work around it later on.

I like to do long rides in the mountains. If I can't get my rear tire off when I get a flat forget about it.

Seems to be a common issue with the new high end ****mano RDs because of the new "shadow" technology.

Ever considered going tubeless? I honestly can't remember the last time I had to remove a wheel on the road.

Ok, not entirely true... the other weekend I did get a flat, but that was on some pretty technical MTB trails on my CX bike with way over-inflated and a bit too narrow tires for the terrain so it doesn't count. I didn't remove my wheel, I just re-inflated it a bit after it sealed up, but if I did have a tube, I might have.

But... I can't remember the last time I had to remove a wheel on my ROAD bike short of just swapping between short and deep section wheels.

6800-GS is probably going to be hit or miss depending on the bike and length/angle of the hangar when trying to get a 34t in there. Top jockey with the b-screw all the way in on my Crockett is really close with a 32t. I'd be surprised if I'd be able to get anything bigger in there, but might be worth a try.

What do you mean it is hard to get off? How is the cassette getting in the way of the RD? Are you swinging the cage out of the way when you try to pull the wheel out?

It may be easier to remove the wheel if you take the QR skewer out completely (mind the springs!). The knob on the drive-side end of the skewer can foul on the RD body.

I have used both 6800 and 8000 rear derailleurs on my current bike. With the slightly longer 8000GS rd, it is slightly more difficult to remove the rear wheel. But here's the trick . . . you have to push the end of the cage down manually (a 1-finger operation) while moving the wheel downward. If you're in the 11 cog, the cage practically doubles back on itself and it doesn't want to pop loose as it does on the 6800.

Another idea would be to shift a few cogs up from the 11T so that the cage isn't at such a steep angle. If it's not at that sharp angle, the wheel should pop out just as on the 6800. Mine has thru axles, but I haven't had a problem since I figured out I have to push the cage down.

So, if I'm pulling out the wheel, RD fully extended, the RD does not swing wide open enough to let the cassette clear. And then, on the other side, my disc rotor will not clear the frame. I'm going to look more into this tonight.

Might go tubeless now. But, still on the fence.

Tried that, still won't clear.

Thanks, going to try this!

Are you using a larger-than-stock tire size?


The RD, with the QR skewer removed, should have nothing to do with the ease of removing a wheel. With the Shadow+ tech, the RD parallelogram and cage are (relative to the axle) more forward than 6800...of course if you're using a hanger-mount frame and not a direct-mount frame the geomoetry is a crapshoot. Which is part of the point of DM--standardizing the crapshoot of RD hanger non-standard placement of the RD.


https://www.bikeforums.net/20158928-post1.html

Yes I'm running 28C. Never had an issue with tires clearing before.

Wait, so new R800 can be direct mount or hanger? Wonder if I have mine on wrong.

The new Supersix ultegra comes with r8000, gonna see how its setup stock I guess.

There was a big thread over on WW about this. I forget some of the details, but the issue was with bikes that have little clearance for the wheel to move forward after coming down out the dropouts, usually because of a chainstay bridge or BB reinforcement that comes very close to the front of the wheel. It's a big enough issue that Sky created an aftermarket derailleur hanger to move the RD slightly rearward.

Yes. And IMHO it shifts better DM rather than hanger...but manufacturers are dragging their feet using DM on road.



Out of the box, the R8000 part comes with the "extra" B-knuckle installed for hanger-mounting. Have you asked a shop about this and had them look IRL at it? Something is hinky, and we can play 20-Questions all week, but we're not getting anywhere.