Hello. The Silent runner is a great wheel but I opted for an open wheel for our robo as I was worried he'd miss the gaps/holes in the wheel when jumping out and hurt himself. Assume it's the 9" one. A 9" wheel is fine for a robo though
The 9" wood trixie wheel might be good. But it would need plastikoting or it'll get pee stained. Plastikote enamel paint (the water based paint on one) is pet safe, doesn't smell, quick and easy to paint on and it makes it wipe clean - I painted the cork surface as well as the wood wheel.
https://www.zooplus.co.uk/shop/small..._wheels/609617
The plastikote comes in clear or various colours. Dry in a couple of hours although I usually wait till the next day to do a second coat. A little pot goes a long way.
https://www.amazon.co.uk/Plastikote-...4&sr=8-11&th=1
I actually had the Rodipet version of this wheel which our robo loved, but it's a bit expensive. It's height adjustable.
https://www.rodipet.co.uk/exercise-w...ise-wheel.html
Both are silent