Campagnolo 8 speed cassette on 9/10/11 speed hub

Hello out there!
I am completely new to this, so if you want to help me, be nice and clear! Thanks!
Currently I am running 8 speed cassette on my F.Moser.
I am looking for Campagnolo Vento Asymmetric G3 Wheelset and I would like to know whether it would be possible to use my 8 speed cassette on those Vento wheels. Would it be possible to use spacer?
Or do I need to buy 9 speed cassette, but then I can't use all 9 speeds, because I have 8 speed ergo shifters.
Any help is appreciated!
Thank you in advance!

Greetings, Archie

If you want to run 8 speed on a later hub, you need to adapt a 9 speed cassette. Remove one of the sprockets and swap the Campag spacers for a set of Wheels Mfg Shift-8 spacers.

However, Wheels Mfg have discontinued the Shift-8 kit, so you will be looking for a second-hand kit (good luck with that).

I have seen an 8 speed cassette jammed onto a 9 speed freehub: trashed the freehub and the shifting was all over the place.

Campag 8 speed spacers in a 9 speed cassette won't work: 9 speed sprockets are thinner than 8 speed, so 8 speed spacers aren't thick enough.

An unmodified 9 speed cassette won't work with 8 speed shifters: centre-to-centre (ctc) 8 speed spacing is 5.0mm and ctc 9 speed spacing is 4.55mm.

TL/DR Technically it's possible to run 8 speed, but realistically you need to upgrade your drivetrain.

Thank you for your answer!
However, I dont get this part - "swap the Campag spacers for a set of Wheels Mfg Shift-8 spacers", and what is "Mfg"?

https://wheelsmfg.com/

The distance between 8 speed sprockets (the ctc distance) is different to 9 speed, so as well as removing a sprocket from the 9 speed cassette, you also need to change the spacing (increase it from 4.55mm to 5.0mm).

This is where the Wheels Mfg spacers come in.

I forgot to mention that you'll also need a 9 speed chain.

However as I said all this is pretty much academic, because they no longer make the kit (not that I remember it being readily available in the UK), so you'll need to find one second-hand.

And while you're looking for that, you might as well see if you can get a unicorn...

An 8 speed cassette does fit the splines of the modern freehub. You will get some gouging of the splines but it will work. You will however need a 1mm spacer behind the cassette for a campagnolo freehub, don't know where you will get one of those unless a standard freehub spacer fits and you know what I have never tried.

Those wheels manufacturing kits are no longer available finding one is not easy. Luck is required.

You will however need a 1mm spacer behind the cassette for a campagnolo freehub...

No spacer on the one I had in, which would explain why the shifting was so poor and the freehub trashed.

If my maths is right, an 8 speed cassette is 36.9mm in total and 9 speed 38.2mm. If you add a 1mm spacer, that leaves 0.3mm unaccounted for: what happens to that?

find a very thin spacer then. The width you have quoted is cassette width but the big cog is dished. the freehub length between 8 an 9/10/11 speed is less than 1.3mm i think. not sure exactly.