I find a lot of 1:25/24 scale tires fit reasonably well on a Dremel sanding drum tool. I chuck that up in a variable speed dremel, and hold a sheet of sandpaper against the tread area while I turn the tool at a slow to medium rpm.
This brings up a discussion I had yesterday. A few of us from the local model car club got together to celebrate black friday at one of the LHSs. We met for lunch afterwards, and a long discussion began between folks who liked rubber tires and those who liked styrene cast tires. Those of us who liked the later were ones who liked to paint tires, either for correcting the shade of color or for weathering. The vinyl they use on the "rubber" tires cannot be painted with anything anyone in the group could find. The styrene tires can always be painted. Both types, however, can be sanded, to remove mold lines and to take the sheen off of them.
I guess the advantage of the vinyl/rubber tires is that they look almost okay with no work, but if you want them to look really good you have to do some work on them anyway, and it may take as much work or more than what you have to do on styrene tires.