Some possibilities came to my mind right way! Making wheels was one and the first result is here.
It's not a quality result, but it may be usefull.
I made 2 sizes: 2 of them about 4,7cm and other two were 5,5 cm. They... shrink.
Those were too small, and I had one problem with that other wheel...
You can compare the result of the 5,5 wheel with a cannon wheel from an Italeri napoleonic set. The cannon wheel is bigger.
Hope you like it.