In reply to Bjartur i Sumarhus:
I’m a shimano man not a campag but if this situation was for shimano, an 11 speed wheel would fit a 10 speed set up quite easily by using a 1.8mm spacer on the free hub before dropping the 10 speed cassette on. I do this all the time as my winter bike is an 8 speed claris and nice bike 11 speed, all my wheels are 11 speed but all fit the 8 speed with this spacer.
note though that you can make wheels for higher number of cogs fit wheels for lower numbers but not the other way around, that is, 8/9/10 speeds can’t fit the 11 speed cassettes. you have to have the 11 speed free hub to start with.
I imagine campag are similar, just need a campag rider to confirm this.
Post edited at 11:07