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A Tire for All Terrain

I am going to purchase a mountain bike for trail riding. I also do a bit of riding on country roads. Can tires be swapped on a mountain bike for the different conditions vs. buying two bikes?

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

For your first purchase, I think it's wise to bring home a mountain bike. Also known as an all terrain bike, an ATB is well suited to riding on the road as well as off. There are several approaches to solving your dilemma of riding with the appropriate tire.

First, of course, would be to buy an altogether different bike that comes equipped with not only slimmer and slicker treads, but also different gearing and handlebar design. This solution, however, comes at a pretty high price — that is, unless you run across an incredibly good deal on a new or used bike. But the advantages of having another bike (and it's almost impossible to have too many bikes) already set up for on-road riding may ultimately cancel out any financial burden.

But the reality for most of us is to look at another choice. The cheapest solution is to purchase different tires and change them back and forth according to which type surface you will be riding on. Since tires can be easily rolled up and stowed in a jersey or a fanny pack, it becomes possible to change tires in media res, so to speak. The obvious disadvantage to this method is that you will have to physically remove the tire each time you want to change tread design and tire size. But with practice, it isn't all that difficult. In ten easy minutes, you can change both front and rear tires and be on your way.

But you may not want or need to change both tires. If you are already running a fairly narrow front knobby tire, say a 26 x 1.75, you may elect to keep the front on unless you are planning a rather long ride on a smooth surface. Since the weight is placed more directly on the rear tire — which therefore is more subject to the effects of rolling resistance — you may want to change the rear tire's knobby, off-road design for a 1.5 slick.

And when I say"slick," I mean "slick." A rear tire can maintain perfect traction with absolutely no tread whatsoever. (For that matter, if all you are riding is asphalt and similar smooth surfaces, the front tire requires no tread either.) In fact, most manufacturers of road tires place tiny little ridges to make it appear as though there are functional treads because that's what uninformed cyclists expect works better.

Another approach is to buy an extra wheel or two for mounting the specific tire(s) you decide to use. This means, however, that you cannot easily change tires in the middle of a ride unless you plan on carrying them with you somehow, which is not practical for most day rides.

One tire that is available (but which generally does not live up to expectations for most cyclists) has a smooth interior tread, with outer knobs. While the theory appears sound (smooth tread for going straight and knobs for better cornering), in practice the outer knobs provide unpredictable performance and can suddenly "over-grab," which is a bad thing to happen with one's front tire.

Take some time to shop around for different tires and chances are good you will find just the right combination for the kind of riding you do.

Thanks for the question.