I would recommend either the plastic Trixie wheel or wooden Trixie wheel - I have both these wheels but the 28cm size. I find they are both fairly quite and all you can hear is the pitter patter of their feet. The wooden wheel can be Plastikote to protect the wheel and also aid with cleaning.
Here are links for both ...
Plastic 20cm -
Trixie Small Pet Exercise Wheel | Free P&P on orders £29+ at zooplus! (also avialble on amazon)
Wooden 21cm -
Trixie Wooden Exercise Wheel | Free P&P on orders £29+ at zooplus!
A couple of other 8” wheels I can think of are the junior wodent wheel (
https://www.petplanet.co.uk/product_...446&pg_id=2767). Their is also the silent runner however that’s not available in 8” but 9” -
Silent Runner 9 Inch. I don’t have any experience with these 2 wheels though.