[racinghamster]

I would need to find a link to the cage cypher but the base is deep. I was able to use a medium silent spinner in one with the metal wheel base nailed onto a 1" inch slab of wood! This was to prevent the wheel rattling about or moving. I just covered the base with substrate. I suppose if the wheel was sat on top of five inches of substrate however this might make the top of the wheel hit the top of the cage! But my base being wood, I was able to have a thin layer of shavings underneath it and then cover it over with just enough shavings for the robo to leap on and off comfortably without the area being too deep.

I found that my robos never dug down deep except inside their next, so I would `top-up`the shavings as necessary when spot cleaning but never found the depth needed to be more then a few inches.