Technical FAQ: Drivetrain compatibility for 10- and 11-speed

This week, we’ll address a number of questions on cross-compatibility between Campagnolo, Shimano, and SRAM drivetrains. I’m just about done with a whole lot of testing of shifting cross-compatibility of 11-speed systems and will tell you all about it soon.

Campy and SRAM 11-speed?

Dear Lennard,
I’d like to take advantage of SRAM’s WiFli 32T cogset for my aging legs. If I convert my bike to all SRAM 22, but retain the bike’s present Campy 11-speed Super Record (50/34) crank, will my front shifting be compromised?
—Mark

Dear Mark,
No, your front shifting will not be compromised; it will work fine.
―Lennard

Champy and Shimano 11-speed?

Dear Lennard,
I can’t recall if this has been asked on your tech column or not, but do you know the real-world compatibility situation between Campagnolo 11 and Shimano 11 wheels? Specifically, do you know if a Campagnolo 11spd wheel will work on a Shimano 11spd bike?
—Dave

Dear Mark and Dave,
Yes, a Campagnolo 11-speed wheel will work on a Shimano 11-speed bike. I’m just about done with a whole lot of testing of 11-speed cross-compatibility of the three brands and will tell you all about soon.
―Lennard

Using an 11-speed Ultegra derailleur in a 10-speed system

Dear Lennard,
Can I drop an Ultegra RD-6800 GS rear derailleur into a 6700 system with the intention of moving to a 10-speed 12-32T cassette? I’m pretty sure I could do it with a RD-6700 GS, but if I could “step up” and put more money into the economy, what the hell? I’m fearing the newly-designed cables could be my downfall, leading to needing the right shifters and then the whole system is committed to 11-speed.
—Bruce

Dear Bruce,
Yes, you could certainly do it with the 6700 GS rear derailleur. Depending on the length and orientation of your derailleur hanger, you may need to really crank in the b-screw, or even turn it around and put it in from the backside to get it to rotate the derailleur further back, but it will work.

As for using the 11-speed 6800 GS rear derailleur, I haven’t tried it. I’m not sure why you’d want to put that in unless you’re planning on gradually converting your whole bike to that over time. I’d be surprised if it didn’t work, but no guarantees. It is possible that the wider 10-speed chain might scrape a bit through the narrower jockey wheel cage, but when we went from 9-speed to 10-speed, it wasn’t an issue running a 9-speed chain through a 10-speed rear derailleur on a 9-speed system. There has been a change in cable pull ratio for the new 11-speed Shimano front derailleurs, so I doubt you could substitute one of those into your system, but I don’t have knowledge of that having happened with the rear shifting.

As for the cables, the new cables for Shimano 11-speed are coated and the housing is still a standard 4mm diameter. This will work fine on a 10-speed system, and I’d be surprised if standard cables and housing didn’t work with the substitution you’re pondering. Let me know what happens if you try it.

I won’t use my usual method to find out about Shimano compatibility issues in this instance. My source for questions like this, if I haven’t tested it myself, is Shimano VP Wayne Stetina. He is currently bedside with his brother Dale in Boulder Community hospital after a terrible bike crash on Saturday. Let’s all keep them in our thoughts for Dale’s full recovery. Updates are here.
―Lennard

Forcing 11-speed on 10-speed hubs

Dear Lennard,
I’ve just ordered an Ultegra 6800 group to build up a new bike. The group I ordered does not include hubs, as I intended to use wheels I already have that use Ultegra 6700 hubs. But now I’m seeing information (or mis-information) that the 11-speed cassette that comes with the Ultegra 6800 group won’t work with the Ultegra 6700 hubs. So, what’s the real story here? If the 11-speed cassette won’t work on a “stock” 6700 hub, is there any workaround, like replacing the freehub?
—Tom

Dear Tom,
Indeed, that information is correct. The Shimano (and SRAM) 11-speed freehub is wider than the 10-speed one, because the 11-speed Shimano (and SRAM) cogset stack height is taller than 10-speed. Even if you were to get the cassette lockring engaged by shoving those 11-speed cogs together as tightly as you could while you were screwing in the lockring, you wouldn’t get much thread engagement, and the first cog’s splines would not overlap the 10-speed freehub body’s splines. I’ve tried this; the lockring will thread in maybe one turn, but the first cog is not engaged; it will spin until the lockring binds it down as it turns it together with it. But if you were to apply a chain load, that cog would either just spin or it would continue to force the lockring to screw in more until the one or two threads holding it stripped, and then all of your cogs would come loose.

And even if you were to feel comfortable with the thread and spline engagement you got, the face of your lockring would rub on the inner face of your dropout when you installed the wheel in your bike. Yes, you could throw a little washer in there between the end of the hub and the dropout, but you’d still have the problem of a disengaged first cog and a lockring only holding on by the hair of its chinny chin chin.

The fix on some wheels is to get an 11-speed freehub body and a different set of axle end caps or spacers or a new 11-speed axle, but not all generations within a given brand are interchangeable. The fix is to interchange the freehub bodies and put more spacing on the axle’s drive end and less spacing on the axle’s non-drive end. Then you’d re-dish the wheel more to the drive side. I recently went through this with Zipp, and the re-dish amount was 1.85mm. Thing is, only 2012 and later Zipp wheels can be converted to 11-speed.

However, there is a fix for those with wheels that are not convertible to Shimano 11-speed freehubs but that offer Campagnolo freehubs (as you might imagine, Shimano is not one of those). You can install a Campagnolo freehub body on your wheel and get a Campagnolo 11-speed cogset. It will shift fine with a Shimano or SRAM 11-speed system.

And in case any of you were wondering, if you have a 10-speed Shimano or SRAM system and buy a wheelset now, you can still run 10-speed cogs on that wheel. To put a 10-speed cogset on an 11-speed freehub, you just put a spacer behind the largest cog. Many 11-speed wheels come with this spacer.
―Lennard