OVER INFLATION MAY CAUSE:

• Loss of tire traction
• Excessive soil compaction
• Fast wear both in field and on road
• higher fuel consumption
• Fewer acres tilled per day
• Harsh ride
• Impact breaks

UNDER INFLATION MAY CAUSE: 

• Sidewall damage
• Poor ride
• Bead un-seating
• Fast wear

Whether you are working with tractor tire or heavy equipment tire pressure, understanding the correct psi and how to correctly determine the right tire pressure for your situation. 

When calculating the right tire pressure, you should consider: 

• Traction
• Compaction
• Wear
• Fuel Efficiency
• Acres worked
• Ride

Tire size and tire location along with the weight of the axle loads of tractors and equipment are important to know when calculating the total load configuration. When you combine the load, with the tire size and speed of the operation you need to perform, you can determine the recommended tire pressure. Utilize these tire pressure charts to calculate the correct minimum psi based on tire size and load limits. 

Single tractor tire load pressure chart
Dual tractor tire load pressure chart
Triple tractor tire load pressure chart

This is a myth from the bias tire days when ANY kind of sidewall bulge meant the BIAS TIRE was low on air. RADIAL TIRES MUST HAVE A CERTAIN BULGE in order for the tire to develop its superior traction. (DIAGRAM INSERTED) BIAS TIRES, at their proper inflation, will OUTPULL an OVERINFLATED RADIAL. The radial's superior performance is realized only with proper inflation. 

Unfortunately, they do not always set the inflation properly. New tractor tires are normally inflated to 30 psi when shipped from the factory to minimize bouncing on the trailer. Dealers may overlook reducing the tire pressures or may not reduce the pressure to the proper level for the load on the axle. Tire changers often times inflate tire to 35 psi to set the tire beads on the rim. Again, the pressure must be reduced to match the load on the axle. 

SAFETY WARNING: Never exceed 35 psi when mounting. For complete instructions, consult the 1991 Firestone Farm Tire Data Book (D402) available at all Firestone stores and dealers. (do we have anything more recent?)

• Determine the axle load for your tractor.
• A grain elevator scale is best.
• If an elevator scale is not available, call you tractor dealer for the tractor's front and rear axle load.
• Include any cast or liquid weights, tanks, loaders and the implement hitch weight. * 
• Enter your numbers into the Firestone Tire Pressure Calculator and set all of the tires on that axle to the recommended tire pressure psi.**

Follow these steps for the second axle.

*When using heavy 3-point hitch mounted equipment, adjust rear inflation pressures based on the weight being carried on the rear axle with the implement raised. Return to the lower rear inflation pressures when using towed implements. NOTE: For towed implements which transfer heavy vertical loads to the drawbar (i.e., laser scrapers, grain carts), weigh tractor with maximum axle load and adjust inflation accordingly.

**It is very important to use an accurate tire gauge. Checking with a gauge that is off by 2 psi can lead to serious tire durability problems when setting tires at these lower pressures. Tires pressures fluctuate with air temperatures and should always be rechecked on a weekly basis.