Yeah most Silent Spinners don't work very well any more. Strangely enough, Jasper has the new design (6.5 inch), yet can spin his with relative ease (not as easily as his Comfort Wheel). It is slightly harder for him yet he doesn't seem to mind putting the extra effort in. He weighs about 55 grams .
I only use he Silent Spinner for his travel cage though as the Comfort Wheel is too big
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I really like the Comfort Wheel. It spins very freely and are easy to get. I bought mine off Viovet, quite cheaply. It is also easy to dismantle and clean. The only downside is the noise but that's more of my little dwarf hamster's feet tapping loudly on the wheel when he runs.
The Silent Runner is supposed to be excellent, but expensive.