My reasons are #1) most ATVs already have enough power for people that are new to the sport, #2) the correct set of tires for your style of riding may not only add to the comfort of riding, the correct tires may also mean a safer ride.

To choose the correct tires for you,you must first ask yourself what kind of riding you prefer to do, and what kind surface will you be riding on. Will you be trail riding on a nice easy soft clear path ? Will you be riding in lots of mud , sand ,or snow ? Will you riding fast or slow? Or how about some kind of competition riding, MX racing ? Hillclimbs ? Flat track racing ?

I guess my point is with all the different kinds of riding ,tire selection can be important. It is not uncommon for experianced atvers to have more than one set of tires.

Things to consider when purchase a set of tires and why:

1. If you're going buy a set of tires and put them on rims you already have, make sure you purchase the correct WIDTH tire for the rim size that you have because if the tires you buy are to narrow they WILL come off the rim.
2. Do you want a flat tire or a round tire ?If at this point your thinking WHAT ? Walk around to the back of your ATV ,squat down and take a look at the top of the tire (fully inflated to its correct pressure), is the top of the tire flat or is it rounded? Most of the people I know prefer a flat tire. WHY? Because a round tire has a tendancy to roll under during HARD cornering. A flat tire tire puts more rubber to the road, so to speak.
3. Do you want a tall tire or a short tire? If you need to have lots of ground clearance you will need a tall tire,a tall tire will lift the ATV higher off the ground and give you a softer ride, but on the other hand a tall tire has more sidewall flex which will give the atv a feeling of being loose during hard cornering.If you choose a short tire you get more stability during hard cornering and high speeds, but you loose ground clearance and the ride may be a little more bumpy.
4. Tread pattern .There are so many different tread patterns to choose from for different kinds of terrain that if your working with a limited budget (like most of us ), try to choose a tire that will work under general condititions. If you have big bucks and you can afford to buy mud tires, trail tires, sand tires,etc.. then go for it.