All RC tires (and really, all tires) are out of round to a point. The bigger they get, the more out of round they are, it's just a simple fact of life. ThunderbirdJunkie's cheap tires on his Toyota Paseo spun nice and true compared to the $200+/ea tires on his Jeep that are much bigger and generally of higher quality.

On a touring car, 1/10 buggy, or something similar, you can usually take a bit of shake out of the tire with balancing. With MT tires, ThunderbirdJunkie doubts anything significant would come out of it; the tires are just out of round.