Kokiafan

I have a bike that has an Ultegra 6800 drive train and rim brakes, with a long cage rear derailleur.
I am buying a new frame, and will be buying Ultegra 8000 series hydraulic brake levers and brakes.
I would like to keep the old drivetrain, front and rear derailleurs and crank, and I am wondering if I am going to run into trouble using the 8000 series shifters.
Yes, the frame I am buying is set up for disk brakes, and I already have the wheels.

Do you think there will be an issue using the old front and rear derailleurs with the new shifters?
TIA

deacon mark

I have 6800 but I actually upgraded the rear derailleur to the r8000 about 2 years ago and it shifs better. I got the long cage and the angle to the anchor bolt is better. There will be no problem with cranks assumimg yours is in the Shimano recall I am sure, just make sure the cranks are ok. Visual inspection. If you really need to save money they you are ok with the current derailuers and cranks. However, if this were me I would go ahead get the new derailluers and then you have a spare 6800 groupset in effect. You could sell or build another bike. To me this is a no brainer for the difference in money of just 2 derailleurs.

Like I said they a whole new group upgrade including the cranks would not be a downside unless money is simply the issue. A used 6800 groupset that works is nice. Mine has 50000 miles or close on them they shift great.

Iride01 

Does your frame have mount points for disc brakes? Is it wide enough for wheels with disc brakes?

Or is there a hydraulic rim brake option I'm not aware of for the 8020 series?

Never mind, I went back and read the rest of your post a little slower this time.

Kokiafan

UPDATE:
After long covid and an injury, I am back in the game for this build.
I am looking at something like this: Shimano ULTEGRA R8000 R8020 2x11 Speed Groupset R8070 Hydraulic Disc Brakes Set | eBay
Where I get everything I want, and then I could sell almost my entire groupset on the rim brake bike either whole or in parts...

Combine it with something like this: OG-EVKIN CF-025 Carbon Road Frame V-Brake Bicycle Frame Super Light BB86 700C x 25C Di2&Mechanical Bike Frames Frameset Racing (ogevkinbike.com) where I can use my current handlebar setup.
I love the Elves bikes but they all seem to have proprietary stem/handlebar requirements and they use a non-standard seat post. The OG Evkin solves both of those problems.
I really really like having aero bars on my road bike simply to take pressure off of my palms and wrists from time to time, having one piece carbon bars means I have to bin my Profile aero extensions. Which kind of puts the Elves bike out of the running.

Seat, post, and handlebars would come over to the new bike. Crank set would come over to the new bike. Wheels and tires are already purchased, I can take them off the gravel bike and use them on the road bike.

The only thing I am waiting on is a word back from the OG-Evkin people about sizing.
It is crazy, I have been told my current carbon frame (a 52) is too small for me, yet the CF-025 has a recommended size that is almost exactly the same as the road bike I now ride. I really dislike the idea of buying a frame that is too big and then having to figure out what to do with it. I am also sad about not being able to get the Elves bike I want--does anyone here have experience putting regular handlebars on a bike with hidden cables? Maybe that deserves a post all it's own...

BTinNYC 

Looks like a cool build.
IMO the 11 speed Ultegra group is a pinnacle of mechanical shifting.