Off-road tires feature slightly different specifications, than the wheels for the regular vehicles. The first digit in the tire size stands for the outer tire diameter (in inches). The second number of the tire size measurement is the width of tire (inches).
The 3rd number of the off-road tire code reading is the same as in the regular automobile tires and identifies the inner diameter of the tire.
Not every owner of an off-road vehicle knows, what is the outer tire size of the tires they use, and it may be somewhat inconvenient to measure it at a spot.Though, knowing the standard tire size, one may easily calculate the outer diameter with the help of formula. It is important to note, however, that this formula is calculated in millimeters, not inches.
As an example, let us consider the standard wheel size being 245/75-16:
- In the 245/75-16 wheels, the “245” denotes, that the width of the tire is 245 mm;
- The “75” means that the sidewall height is 75% of the tire width (245 mm);
- Sidewall height in mm: 245 mm x 75% = 183.75 mm;
- Conversion of the sidewall height from mm to inches: (183.75 mm x 2)/25.4 = 14.47 inches;
- Height of the side wall in niches has to be added to the wheel diameter in inches (in the example 245/75-16 it is 16): 14.47+16=30.47.
If an owner decides to replace the factory tires will the off-road ones, it is important to consider not only the measurements, but the material and off-road wheel thread specs. Off-road tires are made of way softer rubber with wide and deep treads. Such tires do their job off-road and when travelling over rocky or muddy paths, but they wear fast when used on highways. Besides, off-road tires do not provide that maneuverable cornering, especially at speeds.
Off-Road Tires Specifications (Recommended)
| TRUCK | WEIGHT | TIRE HEIGHT | WHEEL WIDHT |
|---|---|---|---|
| Super light | 1000-1400 kg | 31" - 33" | 10" |
| Light | 1400-1800 kg | 35" - 36" | 12" |
| Medium | 1800-2200 kg | 38" | 14" |
| Heavy | 2200-3000 kg | 44" | 16" |
| Super heavy | 3000+ | Find something bigger! | Find something bigger! |
More about Off-Road Tires
In general, the off-road tire fitment is a little bit more complicated for 4×4 vehicles in comparison with regular cars, because you have to consider the vehicle lift height, suspension travel, and the presence of other modifications that may interfere with larger tires. Wide wheel-to-wheel running boards, mud flaps, bumpers, and other exterior components may require trimming to install bigger wheels and avoid rubbing. If you are looking to upsize in tires but not sure what fitment to choose for your Jeep, truck or SUV, it may be a good idea to check 4x4projects.com to see common examples of modified vehicles with off-road tires and lifts.
