Ballasting a tractor correctly is vital to efficiency. An underweight tractor suffers from excessive tire slip, resulting in faster tread wear and wasted fuel — because the wheels need more revolutions to move the same distance. But an overweight tractor results in compacted soil and wasted fuel from lugging around the extra pounds.
A good rule of thumb, according to Wayne Birkenholz, manager of field engineering for Bridgestone Americas Tire Operations Firestone Ag Tires, is that at 5 mph, a four-wheel-drive tractor should have 100 to 110 pounds of weight for each unit of engine horsepower; mechanical front-wheel-drive and two-wheel-drive tractors should have 130 and 145 pounds of weight per PTO horsepower, respectively.
There are two main ways to get this added weight: dry weights made of solid iron or steel, or liquid ballast placed into the tractor’s tires. Each method has its advantages.
All tractors on radial tires should be ballasted with dry weights rather than any type of liquid ballast. This allows the radial construction to perform as it was designed. Solid weights can be either donut-shaped wheel weights or suitcase weights hung on brackets on the front or back of the tractor. They don’t stiffen tires, so they don’t significantly affect the vehicle’s ride. However, they tend to be more expensive.
Also known as hydroinflation, this ballasting method has been popular due to its relatively low initial cost. While not recommended for radial tires, liquid ballast may be appropriate for loader or utility tractors on bias tires. However, the additives in liquid ballast can corrode your rims. And liquid ballast stiffens the tire, which can lead to a rougher ride, power hop, or even impact breaks.
“To help alleviate some of these concerns when using liquid ballast,” Birkenholz says, “never fill a tire more than 75 percent full with ballast.”
But whichever type of weight you choose, remember that it’s important to balance the weight correctly.
“Most 4WD tractors should have no more than 55 percent of the load on the front axle, while FWD tractors should have 35 percent,” Birkenholz says. “Check your owner’s manual if you’re unsure for your specific model.”
For more information, contact your local Certified Firestone Farm Tire Dealer or visit http://www.firestoneag.com.