What is the method behind the sizing of motorcycle tires? Why do certain motorcycles have certain tire sizes? Do the fatter tires you see on most bikes make the motorcycle handle better? How does one read the tire specification numbers on the tire sidewalls?

These are some of the basic questions I had when I first got into motorcycling. I will address each of these questions based on my research and personal experience.

There are numerous reasons why certain motorcycles have certain tires. As any sales person will tell you in their showroom, the intended use and desired performance of the motorcycle help determine the tire size. For example, most dual-purpose motorcycles like the BMW GS 1200 R and Kawasaki KLX 250 and KLR 650 will have tires suited for both off-road and street use. The KLX 250 tires will be more aggressive on the knobby side than the other dual-purpose motorcycles. Street bikes like the Kawasaki ZZR1200, will have a differently size tire than a touring and dual-purpose bike. Again, it all comes down to the intended use of the motorcycle.

When it comes to replacing the OEM stock tires, it is always wise to use a replacement tire with the same size as the stock tire for which you are replacing. The main reason for this is that the rims on your bike were designed to be outfitted with certain sized tires. Therefore, you need the correct size to fit on the stock rim.

Installing the correct size also implies that the tires have the same circumference. Having two different tire circumferences will have negative effects on your motorcycle