# Ultegra 6800 cranks 10-speed compatible?



## eickmewg

I'm looking to get a new crankset to replace a 105 10-speed set. Is the new Ultegra 6800 crankset 10-speed compatible? I'm happy with the rest of my 10-speed group. Currently using a KMC X10SL chain. Thanks for any input.


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## tihsepa

Yah, it will work fine.


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## Jay Strongbow

You can probably get a smoke'n deal on 6700 right now....fyi.

Supposedly that crank is only compatible with an 11 chain and using one might mess up your rear shifting because they are thinner than 10 speed chains. It may actually work though but with nothing to gain over a 6700 (or another brand of 10 speed crank) I probably wouldn't chance it.


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## eickmewg

I can get a 6800 and a 6750 crankset for the same price. I would prefer the 6800 because of its ability to take both standard and compact chainrings with its "secret" BCD and four-arm design.


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## Jay Strongbow

eickmewg said:


> I can get a 6800 and a 6750 crankset for the same price. I would prefer the 6800 because of *its ability to take both standard and compact chainrings* with its "secret" BCD and four-arm design.


ah, forgot about that. My mistake for saying nothing to gain over 6700.


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## SNS1938

eickmewg said:


> I can get a 6800 and a 6750 crankset for the same price. I would prefer the 6800 because of its ability to take both standard and compact chainrings with its "secret" BCD and four-arm design.


That's my thinking too. One set of arms and you can run what ever ratios you want.

So Shimano say it won't work, but someone has actually run it and there is no noticeable difference?


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## jmess

I have done 2000 miles using a 9750 crank and Ultegra 10-speed (DI2 10-speed in this case). I am using a 6700 10 speed chain. No issues that I can tell. Some say an 11-speed chain shifts better with 11-speed crank and 10-speed gears. The the outer plates are thinner on the 11-speed chain but the rest of the chain dimensions are supposed to be the same.


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## richrugby

Hello newbie here,
have you implemented this? How does running the 6800 crankset with the 10 sp groupset work? I am considering the exact same mix for the same reason. I have the Ultegra 6600 10p set (std crank, FD, RD, 11-28 cassette, chain) and am looking at the 6800 compact crankset (to give the flexibility of std, mid compact, and compact).
- are you using a 10 speed chain? does the front shift ok?
- did you have to go to 11 speed chain? any issues?

Thanks!


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## eickmewg

I ended up piecing together a Dura Ace 7900 group. With careful shopping I got the Dura Ace stuff new for a very reasonable price since the 9000 stuff was out. So, I stayed with 10 speeds and I never did the 6800 crankset experiment. However, everybody seemed to think the 6800 crank would work fine with a 10-speed chain. The downside to the 6800 crank would be the expensive chainrings.


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## richrugby

Thanks. I had hear that the 11 speed chain would fit, but could jam / not shift well in the 10 speed cassette and the issue with the 10 speed chain is that it would not sit well on the 11 chain ring and would 'wobble' on the narrower chain rings and wear the rings more quickly.

Thanks again.


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## Z'mer

richrugby said:


> Thanks. I had hear that the 11 speed chain would fit, but could jam / not shift well in the 10 speed cassette and the issue with the 10 speed chain is that it would not sit well on the 11 chain ring and would 'wobble' on the narrower chain rings and wear the rings more quickly.


Been running a 6800 compact crank for 8 months now with 105 10 speed shifters /derailleurs, 10 speed cassette, and KMC 10 speed chain. 

Works incredibly well. Zero issues, highly recommended. 

The chain you use should follow the cassette, not the crankset. And 11 speed chain is (a lot) more expensive, and likely will wear faster, so I would never use it with 10 speed rears even if it did work fine.

And BTW, the 6800 crank chain rings have the same width as the 6700. This is because the 10 and 11 speed chain inner dimensions are the same. The 11 speed chain has thinner outer plates.

Official word from Shimano is the combination is not supported, but I think that's really for sales reasons. They want people to buy the whole groupset. 
FWIW, I notice the new 105 cranks look just like the 6800 too. They will apparently be available to buy in June, and are $199. list. 
Some UK suppliers show the new 4 bolt 110mm 105 cranks in their listings, but no stock.


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## richrugby

Thanks, I have been on the fence 6750 vs 6800 and am going to pull the trigger on the 6800.

Just to confirm, you don't see any excessive wear on the chain ring teeth?

Thanks!


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## Z'mer

richrugby said:


> Thanks, I have been on the fence 6750 vs 6800 and am going to pull the trigger on the 6800.
> 
> Just to confirm, you don't see any excessive wear on the chain ring teeth?
> 
> Thanks!


No wear problems on the teeth for me. The black anodizing will wear off the surface, but that happens on any black ring. 

Shimano uses the hardest type of alloy rings, which are cold forged. This means a big press machine whacks the teeth area with many tons of pressure to form the shape of the teeth. This process work hardens them in that area, making them extremely strong and resistant to wear. 
In contrast, the previous crank on this bike was an FSA Gossamer. It had machined teeth, meaning a CNC machine removed material to form the teeth shape. Not as good. 

Still, for most cranks, if you keep the chain lubed and replace it when needed, the ring will last a long time. 

I would replace the chain when going with a new crankset, if it has some measurable wear. An old worn out chain can greatly accelerate wear on the chain rings. So I would replace it unless it is new, or close to new. Cassettes are steel, so typically not as vulnerable.


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## richrugby

Thanks for the feedback. I am pretty meticulous wrt to chain care and replacement (new chain waiting for new cranks, now in transit!).

Thanks again.


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## Ventruck

Z'mer said:


> Been running a 6800 compact crank for 8 months now with 105 10 speed shifters /derailleurs, 10 speed cassette, and KMC 10 speed chain.
> 
> Works incredibly well. Zero issues, highly recommended.
> 
> The chain you use should follow the cassette, not the crankset. And 11 speed chain is (a lot) more expensive, and likely will wear faster, so I would never use it with 10 speed rears even if it did work fine.
> 
> And BTW, the 6800 crank chain rings have the same width as the 6700. This is because the 10 and 11 speed chain inner dimensions are the same. The 11 speed chain has thinner outer plates.
> 
> Official word from Shimano is the combination is not supported, but I think that's really for sales reasons. They want people to buy the whole groupset.
> FWIW, I notice the new 105 cranks look just like the 6800 too. They will apparently be available to buy in June, and are $199. list.
> Some UK suppliers show the new 4 bolt 110mm 105 cranks in their listings, but no stock.


sorry for the thread dredge, but this info is EXACTLY what I needed as I've repeatedly heard I'd need an 11-speed chain. I'm still on 10 speed, running a Centaur/7800/Apex mix. Need a new crankset as my RaceFace one is hating me (wearing out at the splines), and while I'd like a 7800 crank, I could get a fresh 6800 for just a bit more.

Thanks.


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