Choosing the correct size for the rear tire for a dirt bike is a necessary step for every dirt biker. If the rear tire for a dirt bike has the wrong size, a dirt biker may lose traction or the dirt bike may behave in an unpredictable manner. If the rear tire has the correct size, however, a dirt biker will feel as if the dirt bike is more stable, and the dirt bike will effectively transmit the power from the dirt bike’s engine to the ground.
Tire size can be expressed through a series of number. The first number represent the width of the tire, in millimeters. The width of the tire impact the size of the contact patch of the tire.
How to Choose the Right Rear Tire for Your Dirt Bike
The contact patch is the portion of the tire that make contact with the ground. The larger the contact patch, the more traction the dirt bike will have, and the more that the tire will be able to “float” over soft surface with the dirt bike. The second number is an aspect ratio of the tire, which represents the height of the sidewall of the tire.
A taller sidewall will provide more cushioning for dirt bikes that ride over rocks or roots in the terrain, but it can make steering less precise on hard packed surfaces. Finally, the third number represent the diameter of the rim of the tire. This value must be equal to the diameter of the wheel of the dirt bike.
Additionally, you can calculate the height of the tire by taking the width of the tire times the aspect ratio, dividing that number by 100, then adding that number to half of the diameter of the rim of the tire. If the size of the tire does not match that of the wheel it is mounted upon, the tire can wear unevenly, or the tire can become displaced on the rim. The type of dirt bike that is ridden will impact the size of the rear tire that is use.
Dirt bikes that are used for motocross events tend to use rear tires with a 19-inch diameter and a relatively low aspect ratio, allowing for the dirt bike to turn quick on the loamy tracks that are used in those events. Enduro dirt bikes will tend to use rear tires with taller sidewalls to allow the tire to absorb the impacts from rocks in the terrain without nosediving into those rocks. Dirt trail bikes tend to use 18-inch rear tires, as those tires provides more stability when ridden over fire roads.
Finally, supermoto dirt bikes will use rear tires with wide tires and low aspect ratios to allow the dirt bike to better turn on asphalt roads. Another factor that will influence the size of the rear tire that a dirt biker should use is the terrain upon which they will be riding. If a dirt biker plans to ride in mud, for instance, he or she should use a rear tire that has deep knob on its surface and that has low air pressure to allow the tire to dig into the mud and to self-clean as it moves.
For those who plan to ride on sandy terrain, however, very wide rear tires or paddle tires should be used with low air pressure to prevent the tire from spinning in place. For those who plan to ride on hard-packed ground or rocks, a rear tire with short, dense lug on the tire can be used, as well as one with higher air pressure. Finally, dirt bikers by those who will encounter a variety of terrain types may best use intermediate treads for the rear tire, as the tires are designed to provide traction in a variety of different terrain conditions.
Another factor to consider for dirt bikes is the air pressure in the rear tire. If the air pressure is too high, the tire will bounce over rocks in the terrain. If the air pressure is too low, the tire could develop “pinch flats.” Air pressure should be checked while the tire is cold.
As the tire heats up due to the dirt biking, the air will expand and the pressure will increase 2 to 3 psi. If a dirt bike use a tube-type tire for the rear wheel, it is possible to use very low air pressure. However, the tube-type tire is more susceptible to “snake bite” punctures in the tire, though.
For dirt bikes with tubeless tires, you can use sealant in the rear tire to prevent these punctures from the rocks in the terrain. Dirt bikes also have symbols on the tire that indicate the maximum speed and weight that the tire can carry. If those symbols are ignored and the dirt bike rides at speeds above those indicated on the tire, the tire may fail.
When installing a new tire on a dirt bike, there are specific steps that must be followed. You must inspect the rotation arrow for the tire to make sure that the tire will spin in the correct direction. If the tire is spinning in the wrong direction, the tire will not be able to develop the proper traction with the ground.
Dirt bikes typically use soap to apply to the bead of the tire to assist in the mounting of the tire to the rim. Additionally, a rim lock may be used for the same reason to ensure that the tire does not spin on the rim while the dirt bike is in motion. Finally, the torque that is applied to the spokes of the tire should be checked after riding the dirt bike for a short period with the new tire.
Due to the vibrations that are created while riding, the spokes can become loosely mount.
