If you are serious enough to tow tires to an auto-x, you probably won't like the weight that that'll add to your car.
If it is JUST for a small tire trailer, i can make one out of aluminum for you... sure, it won't be as cheap as a made-in-taiwan uhaul unit, but it'll weigh a lot less
If it is JUST for a small tire trailer, i can make one out of aluminum for you... sure, it won't be as cheap as a made-in-taiwan uhaul unit, but it'll weigh a lot less