[Kissa]

Syrians need an 8 inch wheel minimum, and a majority need an 11 or 12 inch wheel, which will not fit in rotastak cages. It is likely the wheel is too small for him and it is uncomfortable for him to use. Their backs need to be straight when running on the wheel.

What you should probably do it get a good 11 or 12 inch wheel and make a bin cage/bin addition to the rotastak home out of a good sized plastic storage bin (there's a bin cage tutorial on the top of the housing section). I'd watch him in the rotastak, though, the tubes are a bit small for Syrians and it's difficult to get a cage big enough for a Syrian without spending loads of money on addons. The RSPCA guidelines for cage size is a single level cage of 75 by 40 cm, which I'm 99% sure is impossible with rotastak.