Size and Tractor Tire Pressure
Larger tires require different (typically lower) pressure settings compared to smaller tires.
Contact Patch Area
The main reason is that larger tires have a bigger contact patch area when inflated to the same pressure as a smaller tire. This increased contact patch area distributes the load over a greater surface area, allowing the use of lower pressures while still adequately supporting the weight.
The larger contact patch provides:
- More traction and grip
- Less ground pressure/compaction
- Smoother ride by enveloping obstacles better
Tire Deflection
Larger tires can deflect and deform more at lower pressures compared to smaller tires. This increased deflection provides better shock absorption over bumps and obstacles while still maintaining sufficient air volume to prevent bottoming out.
Sidewall Flexibility
Larger tires tend to have more flexible sidewalls that can flex and deform more easily at lower pressures. This sidewall flexibility enhances the tire's ability to conform to the terrain.
Rim Width
Wider tires need wider rims to properly support the tire's shape and air volume. The wider rim allows the tire to be run at lower pressures without excessive sidewall bulging or risk of the bead unseating.
Hoop Stress
For a given pressure, the hoop stress (tensile force) on the tire casing is higher for a larger diameter tire. Running lower pressures in larger tires reduces this hoop stress to acceptable levels to prevent casing damage or tire separation from the rim.
In summary, the larger air volume, bigger contact patch, and more flexible casing of larger tires allows them to be inflated to lower pressures compared to smaller tires, while still providing adequate load support, traction, and shock absorption. Proper pressure is critical to optimizing the performance of any tire size.
If you need any further help or have any questions about service, tractors, implements, or anything else equipment-related, please contact your dealer, local mechanic, or call us at 602-734-9944. Please ask about our current new and used tractor supply.
If you are looking for old, vintage, classic, or new tractor parts, send us a part request.
Team Tractor Ranch - #1 Tractor Dealer in Arizona. We sell and service most major brands of tractors including Yanmar, Kubota, John Deere, TYM, Mahindra, Kioti, Case, New Holland, Massey Ferguson, Ford, Deutz, Case IH, Farmall, International Harvester, Branson Tractors, LS, Shibura, Claas Tractor, McCormick Tractors, Valtra, Solis, YTO, Montana, and Nortrac.
