bunsen

I've a Spesh Allez Sport 2020, 9spd. I have since installed Mavic Askium rimset and other things. I am wondering that since the cassette is 9spd, is it possible to somehow install an 11 speed cassette (R8000 11 spd). Installing shifter level set is a given and I've already installed R8000 callipers (which are very strong, compared to the stock Sora's that were installed.).
I checked the specs, since I currently have a 9s HG400 cassette installed. Differences noticed in specs are that the R8000 cassette is like 2.5 cm longer. Can I shave 2.5 cm from the existing stuff on the rim????

I do not want to damage the frame with chain rub. Thanks in advance.
Bunsen.

bboy314

Step one: check to see if the rear wheel you installed is 11 speed compatible.

HillRider

^^This. If it is not, you can install an 11-speed cassette on an 8/9/10-speed freehub body if the largest cog is 34T (check this, it may have to be bigger) or more since it will clear the spokes.

Iride01 

If the wheelset bought as a 9 speed wheelset, probably not. But knowing the part number and model of the freehub or hub might help get you better guesses from us.

Don't try to make it work. The designers and engineers probably didn't leave much extra material on anything that isn't needed for it to last a reasonable time in use.

If you want 11 speed then find out if the freehub can be changed or just have your LBS rebuild the wheel with the correct hub. A hub with a freehub and the labor to rebuild the wheel will probably be less than you imagine.

Better price the shifters and other stuff you'll need to go 11 speed.

redlude97

mavic wheels generally are all 11 speed compatible, they're designed with a spacer used behind 9/10 speed cassettes so the freehub bodies were interchangeable with campy freehub body lengths