It's easy to take bicycle tires for granted. After all, with road models there's only about an inch of rubber meeting the road per tire, and only a smidge more even on mountain-bike knobbies and fat cruiser whitewalls. Yet, when you consider that you balance your bicycle on only two wheels at sometimes car-like speeds; that your tires have to grip on rain-slick pavement and muddy backcountry trails; and that they can corner with the fastest wheeled vehicles and climb and descend the steepest pitches, you begin to understand how important it is to have top tires on all your bikes.
Like road tires, mountain-bike tires are best evaluated by a trained eye based on how much tread they had when they were new. Another gauge is how they ride. As the knobs wear down, traction lessens and you'll feel this on climbs and in the corners. The smaller knobs also mean less protection for the tube, so it can lead to more flats, too. These are signs that it's time for new tires.
When shopping for tires, you must match diameters, so if you have 26-inch wheels, only 26-inch tires will fit. You can usually change widths if you want, however. And this is a good way to change the ride quality, too. For example, switching from a 26 x 1.5 tire to a 2.0 model puts you on a wider tire that holds more air, which you might like for more comfort, traction and control. Conversely, a roadie might switch from 700 x 28c tires to 23c tires to save a little weight for easier climbing and faster acceleration. While, if you were suffering frequent flats and a rough ride on narrow tires, you'd benefit by switching to wider tires for more protection and comfort
The tread is the rubber that meets the road or trail. On road tires more tread usually means increased wear along with additional weight, so it's a tradeoff whether you require top ride quality or durability. Road tread varies in hardness, too, with harder rubbers wearing longer while softer compounds grip better in corners. These are fine distinctions widely debated among riders. You'll even find tires with dual-compound tread designed for good wear and top traction. And tread specifically designed for wet roads, as well.
For off-road riding, the amount of tread and the pattern of the tread determine the ride quality, traction and control. Manufacturers strive to design tread that provides the exact handling and characteristics for the different types of off-road terrain, riding and conditions. For example, if you ride in the mud and snow, there are tires designed specifically for these conditions.
How to choose: What's best has mostly to do with how and where you ride so if you can tell us that, we can point out some of our most popular tires for different types of riding. Another way to determine which tires are right is to ask friends you ride with who may have found models they recommend.
We hope these tips help and we look forward to seeing you when need new tires!
Special thanks to BikeMine, Continental and Vittoria Tires for supplying the great pictures.