Have you tried the Quality Cage Chin Spin? It's also a great wheel, and costs much less than the Leo Braun used to. I just wanted a Leo to see what all the fuss was about.
I have a white leo braun wheel in my garage that I need to get rid of...I'm pretty sure it's the bigger size. It came with a surrendered pair I got about 3-4 years ago. Any interest? lol I'll have to find it, take pics and measurements...
Have you tried the Ware Flying Saucers? They're real cheap, so they're easily replacable, they're quiet, and you can take them out of the cage really easily.
It took a day or two for my chins to figure it out but they love it now.
I got mine Here