1. Pick The Right Design For The Job

Tire and Rim Association tire type codes are an excellent guide for determining the type of service for which a tire is intended. Use an R-1 tire (UltraTorque® radial or Duratorque® for example) for general dry land farming. Use an R-1W (Super Traction Radial, DT800™, DT810™ or DT820™) for farming in wet, moist, heavy clay soils. An R-1W offers about 25% more tread depth than a conventional R-1 tire to give good traction without clogging in wet, heavy clay soils. Use an R-2 for farming in wet muck and mud, such as rice or sugar cane farming. An R-2 tire has twice the tread depth as an R-1 tire to dig in the mud without clogging. Using a tire for any service not listed for it will result in poor performance and/or poor tire life. An R-2 (Special Sure Grip® TD-8) tire used in general dry land farming will wear more quickly, not pull as well and provide a rougher ride than the R-1 that you should be using. An R-1 used in sand service will bury itself quickly when asked to pull, whereas an All Weather® Radial (R-3) will be better able to stay on top of loose sand.

Special Cases

Rear tractor tires used on the drive wheels of combines are applied using special consideration for the cyclic loading encountered in this service. For proper loads and inflation pressures in this application, refer to the extended load tables.

Speeds Other Than Field Service

Usually, transport conditions require a decrease in load. Read the notes at the bottom of the appropriate load table to find out how much.

Hillside Combines

Increases in tire load are not permitted for tires on hillside combines. (A hillside combine is a combine designed to operate on slopes steeper than 11 degrees or 20% grade.) The inflation pressure in the downhill tire may be increased four psi for stability.

Furrow Wheels

If you are plowing with one wheel in the furrow, you should increase the inflation pressure in that tire to four psi over the pressure shown in the tables.

2. Pick A Tire To Carry The Load

A tire must be large enough and/or of high enough ply rating to be able to carry the maximum load that you intend to place on it. When determining maximum load, remember to include the weight of full bins or tanks, tillage tools carried on the tractor, and all ballasts including liquid fill in the tires. The air in the tire enables it to carry the load – thus, you get more load capacity by either using a bigger tire (more air volume) or by using a higher ply rating tire (more air pressure) or both. A ten ply rating tire operated at six ply rating pressure will only carry the load of a six ply rating tire. To get the best results, a tire should be inflated to a pressure appropriate for the load on it. See Weight Distribution Front/Rear below.

3. Pick A Tire To Handle The Horsepower

All tires must be sized for the load requirements that they encounter, but a rear tractor tire must meet an additional requirement – it must be able to get the tractor horsepower to the ground. Each rear tractor size and ply rating has a maximum amount of pull that it can handle without shortening its life. Since the horsepower a tire transmits can be calculated from knowing its pull and travel speed, the horsepower capabilities tables show the maximum PTO horsepower that each size and ply rating will handle at different speeds – five mph and three mph. Notice that as speed decreases the amount of horsepower that a given tire will handle also decreases. Virtually all tractor manufacturers agree that higher plowing speeds result in less wear and tear on both tractor and tires. The best speed to pull your implement is at least 5 mph.

4. Check The Size

These measurements are useful when trying to match different sizes of tires. Section Width or SD is the overall width of the tire cross-section. Overall Diameter or OD is the diameter of a new inflated tire measured at the centerline. Static Loaded Radius or SLR is extremely important for mechanically driven front wheel assist tractors. The Loaded Section Width is important for determining whether a tire will fit between crop rows. When changing to a larger size tire, please leave about two inches of clearance between the tire and any machine parts that it comes close to. The distance between sidewalls for duals should be 1.5 inches plus 10% of the section width (SD) for bias tires and 2.5 inches plus 10% of the tire width for radial tires.

5. Weight Your Tractor Properly

A tire on a tractor can meet all of the other criteria and still not provide optimum service because the vehicle is improperly ballasted. Generally speaking, you may choose between traction or flotation – whatever you do to increase one will decrease the other. For flotation, a large low ply rating tire operating at relatively low pressure with a light load on it is needed. Traction requires a higher ply rating tire operating at maximum pressure with a heavy load. Since the amount of pull that a tire will generate before spinning is strongly dependent on load, keeping a certain amount of flotation will require very large tires or duals. Duals can provide either flotation or traction depending on how they are weighted and inflated. Unballasted at 12 psi, duals will give good flotation. When ballasted to maximum rated load at maximum rated pressure, however, duals will produce considerably more drawbar pull than the same size single tire. Note: Be careful not to exceed the manufacturer’s recommendations for total axle and/or vehicle weight. Weight distribution is also very important in farm tractors. Recommended front/rear weight distributions for various types of tractors are shown below:

These weight distributions will be suitable for most general farming applications.
Consult your tractor manufacturer for special cases.

6. Consult Your Titan/Goodyear Dealer

If you have checked all of these points and still have questions, read the sections titled “Things You Should Know About Farm Tires” and “Optimum Tractor Tire Performance” or consult your local Titan/Goodyear Farm Tire retailer.