Originally Posted by
jamestitin
i would like to know is that possible changing from 9spd free-hub to 11spd free-hub?
my new bike come with 105/11spd. but my old bike wheel set is ultegra 9spd hub. can i just change the free-hub to 11spd so i can use that old wheel set for training and will not waste money?
Even if it will not, which might be very likely depending on the exact hub you have, it's not costly to replace them on most hubs.
If you have the skill needed to unscrew and replace the cassette, then certainly you can replace the free hub body. There might be other things you'll encounter, but they too shouldn't be costly or insurmountable. You might find the wheel needs to be dished differently. Maybe not. You might need different axle spacers. Maybe not. Will it be perfect? Does perfection matter for the purpose you are using it for?
It all depends on exactly what you have and are getting. So finding out exactly what the hub and freehub body are that are on the wheel currently, going to the manufacturer's website and digging for specs will help you determine what you can expect.
Keep us updated on what you encounter.