Easily Calculate Tire Inflation Pressures Based on Load


Farmers can determine the optimum inflation pressure for their metric radial tires, based on load now thanks to Goodyear® Farm Tires, a Titan Tire Corporation brand. The company recently launched a mobile-friendly website called TirePressureCalculator.com.

By visiting TirePressureCalculator.com, the user simply indicates the dimensions of the tire and the load index (which can both be found on the side of the tire) as well as the axle and implement weight,* and the calculator will provide the optimum inflation pressure for the user’s application, as recommended by the Tire and Rim Association.

The calculator works for any brand of metric, agriculture radial tire and is easily accessible from a smartphone, tablet or computer. This eliminates the need for farmers to carry around handbooks and consult large tables of load and inflation data whenever making tire inflation adjustments.

“Inflation pressure is the most important aspect of tire maintenance and should be adjusted based on load. The balance between load and inflation directly affects key performance metrics such as traction, flotation, tire wear and fuel efficiency,” said Scott Sloan, product engineering manager for Goodyear Farm Tires, “but, because load and inflation tables aren’t always accessible in the field, the tendency for farmers is to estimate or simply ignore inflation altogether. Doing so, however, can severely inhibit performance and tire longevity. That’s why we introduced the calculator.”

Overinflation causes loss in performance
According to a study conducted by Ohio State University, overinflating a 20.8R42 radial tire by as little as 8 psi can decrease the footprint area by 33 percent. Experience has shown that a smaller footprint can decrease traction and increase ground-bearing pressure, thereby causing surface soil compaction, which can lead to lower yields.

Another study conducted by the University of California showed that overinflated tractor tires waste fuel and reduce productivity. In a field experiment, a tractor with tires inflated to the proper air pressure used 20 percent less fuel and was 5.7 percent more productive when compared to a tractor with overinflated tires conducting the same stubble-disking operation.

Dennis Buckmaster, an agricultural engineer at Purdue University, says loss in productivity and fuel efficiency is related to the machine’s tractive efficiency, which is the percentage of axle power transmitted to the ground.

“At best, average tractive efficiency is 60 to 80 percent, depending on soil conditions,” said Buckmaster, “but proper inflation pressures can increase efficiency by up to 10 percent. That shift in efficiencies can translate into substantial fuel savings and increased productivity. So, maintaining the proper inflation pressure does have a positive effect on a farmer’s bottom line.”

“In real terms, a typical tractor today has a 160 gallon fuel tank and a 10 percent increase in efficiency results in reduced fuel consumption of 16 gallon per fill,” says Sloan. “That’s the equivalent to saving almost $50 per fill at today’s diesel prices. Over a year’s time, that savings can add up just by adjusting your air inflation pressure.”

Finding the load/inflation sweet spot
There is no factor more important to tire performance and longevity than inflation pressure. The recommendations of the Tire and Rim Association differ based on the size of the tire and the load it will be carrying, and until now, farmers have been inconvenienced with having to consult manufacturers’ handbooks every time they make an adjustment to the load and/or inflation pressure of the tires.

“In order to get the most from your tires, you have to find the sweet spot between load and inflation,” said Sloan. “Doing so hasn’t always been easy, but now that farmers can access an easy-to-use tool from their smartphones, tablets and computers, farmers can find their sweet spot and get the performance they need to achieve maximum productivity.”

Visit TirePressureCalculator.com to find your load/inflation sweet spot.

*Calculating axle weight

This is the calculation of the tractor axle weight plus the weight of the implement. Determine the weight of the front and rear axle of the tractor and implement by referencing the operator’s manual. Run a separate calculation for the front and rear axle as follows:

MFWD tractors

  • Rear axle weight = 60 percent of total tractor weight
  • Front axle weight = 40 percent of total tractor weight
  • Add weight of implement to front or rear axle depending on where it resides

4WD tractors

  • Rear axle weight = 50 percent of total tractor weight
  • Front axle weight = 50 percent of total tractor weight
  • Add weight of implement to front or rear axle depending on where it resides