I'm going to Moab in April for a week to ride. I currently have Specialized Team Control/Team Master tires on my bike. Will the fat knobbies suffice, or should I get semi-slicks or some other type of tire?

Steve Jones's Answer.

	Steve Jones The author of four mountain-biking books, Steve Jones has logged thousands of miles of trails and backroads. Meet Steve Answer Archive Biking Forums

The most important parts of your bike, besides the frame, are the tires. The most important consideration, obviously, is whether or not they hold air. The most expensive tire is nothing but a hard rim if it is flat. Fortunately, most tires don't have a problem keeping air in them as long as the tube is in good shape. (Fixing a flat, even on the trail miles from nowhere, is relatively simple. It is extremely important to find the cause of the flat before re-inserting the tube. A thorn or other sharp object still poking through the tire will produce another flat almost before you can get back on the trail again.)

Let's look at which tires work best for which conditions.

Many mountain bikers, while not actively participating as racers, seek to achieve the most control at the highest speed. That's why there are literally hundreds of different types of tires to choose from.

I would suggest that, unless you are a hard-core mountain biker looking for every edge you can gain on your competition, you stay with a general purpose"knobbie," no matter where you may be riding. While it's true the raised knobs of a fat tire won't be the best style for every off-road situation (for instance, the slick-rock riding you will find in Moab), its overall performance is hard to beat.

If you have a generous budget for tires and you are generally unhappy with the way your current tires handle for the riding you most often do, by all means, experiment. Ask around and check out other tires you see at races and festivals. But I would hesitate to change my tires before heading to a different area of the country (and different riding conditions) without first trying the tires under similar conditions at home. Remember: if it ain't broke, don't fix it.

No matter which type of tires you run on your bike, it is also important to keep the recommended air pressure in them. An under-inflated tire can give what's called a "pinch flat," caused when the rim "bites" the side of the tube after a particularly hard impact. It is interesting to note that an over-inflated tire has its own tendencies to create flats. A thorn, or other sharp object, is much more likely to penetrate the tire than one slightly under-inflated. Also, a softer tire — especially if you're riding a "hard tail" (a bike with no rear suspension) — gives a softer ride.