We do have wheels and tires available for your 2004 Trailblazer. You would need a 22x11-10 to replace the stock size. Any rear tire in that size will be correct for your ATV. If you need a wheel for your model please profile your bike on the website and it will show you available options.
For racing these are not going to be your best bet. They are a fairly heavy wheel and not intended to be used for that application. For racing i would look at either the ITP T-9 wheels in either standard or beadlock. We also have our house brand, Rock racing beadlock wheels for a good price. Make sure your ATV is profiled correctly so you get the correct bolt pattern and offset.
the price you see is for one tire or wheel. if your looking for a set of tires you would order 2 tires, if your looking for a combo you would get 2 tires, 2 wheels, free valve stems, free mounting and free ground freight, when purchasing a combo you get a little more savings.