For off-road enthusiasts, purchasing tires can be quite tricky. The choice is dependent on what type of driving the vehicle is going to be used for. Both tire and thread construction should be considered in making a decision as to the tire that will suit the needs of the owner.
This type of casing is the best for highway use. The casing is generally made of polyester and gives a smooth ride. The tire is steel-belted, which helps hold the thread flat. The disadvantage with this type of casing is that the sidewalls are fairly weak and don’t resist impact very well. Another disadvantage is that the steel belts are fairly stiff and give a bad ride on road imperfections such as corrugations.
These tires have stronger construction than radials and have the same strength in the sidewalls as the threads. They also conform well to road imperfections. The casing is generally made of nylon. This type of tire was originally used for trail running and is still the best for off-road use, due to the flex in the thread. This flex means a smoother ride on off-road tracks. The disadvantage with bias ply is on blacktop: They have less directional stability than radials and tend to wear faster.
Bias belted tires are the best compromise for wheelers who do about 60% percent of their driving on the road. These tires have fiberglass or steel belting around the thread of the tire. This gives a ride characteristic of the radial on the road, but gives a stiff ride off-road unless used on a heavy vehicle.
When purchasing a tire, one should check the thread conformability by pressing down on the thread of the unmounted tire with a finger. Keep in mind, though, that the softer the thread, the faster it will wear. The stiffer thread will last longer, but will give a stiffer ride on off-road tracks.
When choosing a thread pattern, the size and weight of the vehicle has to be a consideration. Thread void ratio (the amount of open space between the thread blocks) will determine the amount of pressure per square inch the tire can put on the ground. A high void ratio will put more contact pressure on a smaller amount of rubber, given the vehicle’s weight. The same void ratio on a larger tire will decrease the contact pressure from the same vehicle. Hence a lighter vehicle, with the same tires, will give less contact pressure than a heavier vehicle. Now, imagine a lighter four-by with a wide, low void ratio tire. Contact pressure, in this case, would be low, giving less traction on any surface. Owners of lighter off-road vehicles should not overlook this potential problem.
This area is easily understood by off-road newbies. When buying a tire, these are the categories in which tires are presented for purchase.
As you can see, purchasing tires for your four-wheel drive vehicle is far from being a hit-and-miss affair, if you are armed with the necessary knowledge. Purchasing the right tire for your needs will enable you to enjoy longer tire life and have the right traction for the type of road traversed most often.