As combines, tractors and grain carts roll into fields this fall, one simple, yet often overlooked, tire tweak can protect next year’s yields, prevent ruts in wet soils and cut fuel bills: setting the correct tire PSI.
While Matt Danner, a fifth-generation Iowa farmer, is a few days away from harvest, you can bet he’ll be keeping an eye on tire psi across his fleet.
“You’ve got to [monitor PSI] preemptively. It all precipitates into larger problems if you don’t take care of [checking psi] up front,” says Danner, co-owner of Templeton Family Farms in Iowa. “It’s about safety first and foremost, and you don’t want tires over-inflated or underinflated.”
Why Harvest Puts Extra Pressure on Tires
Harvest machines carry massive fluctuating loads, making tire management distinct from planting or spraying. While many farmers stick with one tire pressure year-round, the correct tire PSI depends on tire design, weather, field conditions, operating speed and total machine/load weight.
The correct inflation pressure elongates the tire footprint, giving you better flotation, greater traction and lower rolling resistance, so you’re far less apt to get stuck,” says James Tuschner, founder of Ag Tire Talk. He recommends consulting with a certified tire dealer before adjusting tire pressure.
Ignoring tire pressure can lead to a variety of problems, including:
- Deep soil compaction, affecting the following year’s yields
- Increased fuel consumption and slippage
- Premature sidewall and tread wear
- Equipment damage
- Safety risks
Dry field conditions offer some forgiveness, Tuschner explains, however, when wet weather sets in, farmers should be on alert.
“That’s when the tires become more front and center, and every part of the [PSI] being correct is super important to make sure you don’t get stuck,” he adds.
The Science Behind the Footprint
Overinflating tires makes the contact area significantly smaller, concentrating heavy axle weights into a narrow footprint that drives compaction deep into the soil profile. Running the correct, lower PSI allows radial tires to flex, elongating the footprint in both length and width.
The right air pressure distributes machine weight evenly, reducing soil compaction so roots, water and nutrients can move freely through the soil profile rather than hitting a dense barrier.
Every machine has a recommended road pressure and field pressure. Modern tire technologies give growers significantly more flexibility:
- Increased Flexion (IF) tires carry 20% more load at the same PSI compared with standard radials.
- Very High Flexion (VF) tires carry 40% more load compared with standard radials.
Tuschner recommends a Central Tire Inflation System, which allows farmers to adjust tire pressure from the cab. Aftermarket options are available from manufacturers such as NTS Tire Supply and Michelin.
Small Effort, Big Returns
With record-high diesel prices, dialing in tire pressure can reduce fuel consumption by reducing wheel slip and rolling resistance.
“If you get your tire pressure right, you will reduce fuel costs,” Tuschner says.
Underinflated tires cause excessive sidewall wear, while an unevenly inflated tire impacts the other tires because they carry a disproportionate amount of the load.
Before heading to the field, Michigan State University recommends:
- Weigh each axle after the tractor has been properly ballasted.
- Use load and inflation tables available from the tire manufacturer and inflate tires to the lowest recommended pressure for the weight carried per tire.
- Use a high-quality tire gauge that is easy to read, accurate, consistent and graduated in at least 1-PSI increments.
- Check the inflation pressure often and when the tires are cold, preferably in the morning.
- If fluid ballast has been added to the tires, measure inflation pressure with the valve stem in the same position for all tires.
- For optimum performance, set all tires on an axle to the same pressure.
“It’s pretty critical we check everything from planters all the way to fertilizer and harvest equipment,” Danner says. “Now with current diesel prices, it is even more important.”
