calgarc

I am working on my new bike build. i want to buy the ultegra 6800 11 speed derailleurs but run 105 10 speed shifters and cassette. I know i can run the FD just fine, but I should also be able to run the rear derailleur as a 10 speed right?? Or would there be too much slack??

dtrain

From everything I've heard, it should be fine. I actually have a 6800 braze-on FD available for sale:
https://www.bikeforums.net/road-bike-...leurs-new.html

zymphad

You may want to check on that FD too. 6800 has an extended arm so the pull would be different than the 105. It may work, I don't know, but you may want to find out. Unless you already have, then that's good news for me too.

Quite different, 6800 vs 5700.

dtrain

The official Shimano charts don't really show any 11 speed and 10 speed mixing. I know the 5700 shifter wouldn't take advantage of the 6800's redesign...but I thought I'd heard that it'll still work.

The bigger question is why. If wheels and/or shifters are holding the OP back from a full 11-speed build, that's fine. But why not build with 10 speed derailleurs? I don't no about 'slack', but the RD jockey wheels are likely different.

rpenmanparker 

If OP has 10 speed wheels that be doesn 't want to replace, he can run a complete 11 speed group but just remove the smallest cog from the 11 speed cassette. According to an older thread this works with certain lock rings. Then he would adjust the limit screws to only allow 9 shifts to use the 10 cogs.

calgarc

its a new build, I want to go with ultegra mechs purely to make future upgrades easier. especially when the 11 speed 105's come out, i can just swap the wheelset and the shifters

this allows me to enjoy my new bike while i can afford to without having to wait for the 105 set to come out. i am thinking ong term with this as well with this.

BoSoxYacht

a "new" build, but I'm guessing you have the 10 speed shifters?

rpenmanparker 

Considering the occasional phenomenal deals offered by the UK online stores, I would just go Ultegra now. The difference may well be negligible.

calgarc

I do not have money to go full ultegra right now. I can go full 105 with an ultegra FD and save the rest for later. maybe even shell out for a RD if this idea works

calgarc

I have a frame, fork. i recently ordered a headset and bottom bracket

fstshrk

I doubt the FD would work. The 6800 has such short throws, I think you would get very interesting shift behavior with the 105 shifters.

fstshrk

Then wait. 5800 is right around the corner.

kleng

Read the section on "a cautionary tale about ultegra compatibility"

Technical FAQ: Revisiting drivetrain cross-compatibility - VeloNews.com

TheSame

Why not bite the bullet and just buy the entire 6800 group? it's cheap from the UK sellers. I can't imagine 105 5800 being that much cheaper.

Kiko1027

Hey! quick question I have a bike that has 105 components looking to upgrade a piece or two from the components of my bike now to the ultegra 6800? What parts can I switch right off and have no problem since my bike 10 speed and the new groupo is 11 speed?

Kiko1027

I have a question, right now my bike is 10 speed and has 5700 components (shimano) looking to upgrade to some ultegra 6800 parts. Can i switch a thing or two from my current bike parts to the new ultegra 6800 without a problem? or should I just change everything like buy the whole groupo?

dtrain

Calipers are the exact same pull, but 6800 is nicer (from what I hear).

calgarc

i could also go 5700 and upgrade the rear mech and sti for it next year... hell maybe even satisfy a few of my other foot powered obsessions

zymphad

Again, where are you getting that 6800 derailleurs are compatible with 5700 shifters? I just don't see it. The pull and indexing are not the same. The shape and design of 5700 and 6800 are not the same for both RD and FD. Where the cables are attached aren't the same either.

I just don't see how you can upgrade piece by piece. If you upgrade RD and STi, you'll need to upgrade the cassette, chain, crank, wheel (11 spd compatibility), FD, etc.

Just curious where are you getting info you can upgrade piece by piece and where it says the Shimano 10 and 11 spd are interchangeable. I'd like to see a thread with multiple people verifying this is possible.

calgarc

lol what i should have said was upgrade next year when the 5800 is out lol.

ILbikebuilder

I know this an older thread but i think it's still very relevant as millions of 10 speed bikes are getting older and need upgrade and 11 is the new platform. I just tried this scenario with 5603 105 triple shifters and new 5800 double derailleurs front and rear. Front shifts well but requires the entire stroke of the triple shifter to shift the 1 cog of the new 5800 double crank. The rear does not work well though. You can get about 7 or 8 cogs but you can't get the whole 10 speed cassette with the 11 speed rear derailleur. The pull rate is slightly different. I researched this and read elsewhere that the pull ratio would be the same in 11 speed as 10 but it doesn't seem to be true. As an aside for others blending parts the 11 speed front derailleur and crank shifts great with conventional 10 speed chain. I had bought a new directional 11 speed chain thinking it'd be needed for proper front shifting but it's still in the box.

franswa

Millions of 10 speed bikes suddenly useless.

rpenmanparker 

The pull ratios for Shimano 10 and 11-speed derailleur a and levers are different you can't mix 10 and 11-speed in Shimano. That is all.