Larry77

I'm pretty sure they are compatible but I wanted to check with the experts before I make my purchase. I'm upgrading my stock wheelset to the Shimano 6800 which is 11 speed compatible and I figured it was a good opportunity to also upgrade the rear cassette to the Ultregra 11 speed version.

Will I need to do anything besides adjust the rear derailer after the install?

Bike is a 2014 Scott Speedster s20 with stock Syncros wheels and 10 speed Tiagra rear cassette, looking at changing to Shimano 6800 wheelset with Ultregra 6800 11 speed rear cassette.

Thanks for any help,

Jamminatrix

No, it will not work. You need to stick with a 10-speed cassette. The cable pull ratio is different.

dr_lha

To go 11 speed you'd need to get new shifters and derailleur as well. You can't just stick an 11 speed cassette on a 10 speed drivetrain. Well, actually you probably could (as the cog spacing is the same for 10 and 11 speed), but you'd only be able to reach 10 of the 11 gears.

fietsbob

Replace the 10 cassette when it needs it with another 10.. that costly spending for that 11th speed likely is not going to mean much ..

Explain what are you Expecting to get out of It?

Larry77

Well burst my bubble...lol. No worries, will replace with my existing 10 speed cassette. Thanks for your expertise it was amazingly difficult to get the answer online.

I was only looking to add another gear if it was easy, not necessary at my skill level at this time.

fietsbob

Double to triple crank would be a more significant '1 more' probably better to make the Motor work stonger.

HillRider

You can install a 10-speed cassette on an 11-speed freehub using the requires spacer and all of your existing 10-speed components will work fine. If you install an 11-speed cassette, a lot of expensive other things will be needed to make it work, like shifters, rear derailleur and front derailleur.

CafeVelo

You need shifters and derailers, and the spacing is not the same. It's close, but not the same. You probably also need a wheel since bikes spec'd with 10 speed typically dont come with an 11 speed freehub. You could run 10 of 11 cogs but then what would the point be? That upgrade would cost upwards of $500, and more if you want your wheels to match.

HillRider

The OP is already buying 11-speed compatible wheels, which is what started this entire discussion.