[glassdoctor]

Back in the day, most racers put holes in the wheels. Now I think most do holes in the tires... as mentioned, this allows water to get out and lets in less dirt than a hole in the wheel. I use body scissors to notch a small hole in the center of the tread... small leather punch would be cool though, as long as you remember to do it before gluing. :)

But if you are running in mud, etc and not racing... you shouldn't need any holes.