Tires: Your Only Link to the Ground

Your tires must accomplish two things: 

1. Tires provide the traction necessary to move your machine and implement forward. 
2. Tires also need to provide flotation, or prevent your machine from sinking too far into the soil.

Problem is, when you try to improve one, you generally hurt the other. Run with a setup that’s too light, and your wheel slip will be too high. You’ll work slower in the field, wear your tires faster, and burn more fuel than necessary to accomplish the job.

On the other hand, when you hang suitcase weights on your tractor to increase the downward pressure on your tires, you should see better traction. But at the same time, you’ll sink further into the soil and cause more compaction. Without a large enough footprint from your tires to support this extra weight, your fuel efficiency will take a huge hit.

You need to find an acceptable balance between flotation and traction to get the most performance out of your tractor. There are several strategies you can use to find this balance for your operation.

1. Run with the Largest Tire Footprint Possible

You see the problem: Traction and flotation compete with each other. You don’t want to sink too much. You don’t want to spin too much. Your job is to find the right balance for the operation you’re performing, because you have to do a little of both sinking and spinning. Your first step is to make sure you have the largest footprint possible for your machine. 

Dial in the Correct Tire Pressure

Do you know how much air is in your tires? Do you know why? You should calculate the correct pressure for any tire based on load and speed—how much weight the tire has to support and at what speed you’ll be operating. If you simply inflate your tires to whatever max PSI is printed on their sidewalls, you’re cooking up a recipe for wasted fuel. North Dakota researchers found that correctly inflated radial tires improve performance by 6 percent.

As your tire pressure decreases, your tire’s footprints increase in length. This brings 3 big benefits that will increase your efficiency: 

1. More lugs on the ground for increased traction.
2. A larger flat plate (contact patch) for better flotation.
3. More engine power dedicated to moving you forward. 

This is why correct air pressure is absolutely critical to achieving optimum fuel efficiency. However, you can only drop your tire pressure to the minimum safe pressure for your tires based on load and speed. And if you’re relying on old-tech bias-ply tires (or even standard radials), you may not be able to drop your pressure low enough for optimum performance. This is when you need to take the next step: mount larger tires or upgrade to IF/VF radials. 

Mount Larger Tires

The larger a tire’s air chamber, the more “support” it provides to carry the weight of your machine. You can increase your tires’ size by width, height, and aspect ratio. Larger tires will put significantly more footprint on the ground. However, there’s such a thing as tires that are too large for a tractor. Oversized tires actually tend to slip more because there isn’t enough weight on them to cause sidewall deflection. As the sidewall “squishes,” a tire’s footprint gets longer, which, as we learned above, provides better traction and flotation. 

‍Will a change in tire size (a “changeover”) increase your operation’s efficiency? Talk to an NTS Tire Supply tire expert today.

Replace Worn Tires

You’ve spent countless hours doing field work, so trust the feel of your tractor: If it seems to be slipping more than normal, and your tire tread is worn to some degree, it’s definitely time to replace them. Other factors may point to new tires in your future too, such as tires with excessive stubble damage, odd wear patterns, or a slow leak. (You’re checking your tire pressure often with a tire pressure gauge right?)

2. Upgrade to IF/VF Radials

Introduced by Michelin to the ag market in the early 2000s, IF/VF tire technology (increased flexion and very increased flexion) has been around awhile. These top-tech tires bring huge benefits to your operation because IF/VF radials put more tire—a larger footprint—on the ground thanks to lower air pressures and more sidewall flex. As we mentioned above, a larger footprint delivers more traction and flotation at the same time.

• IF radials can carry the same load as a standard radial at 20% less pressure.
• VF radials can carry the same load as a standard radial at 40% less pressure.
• Or, you can increase their maximum loads by 20% or 40% above a standard radial’s limits.

If your tractor’s standard radials (or bias-ply tires) won’t allow you to safely drop your tire pressure under 15 PSI in the field, you should look at an IF/VF tire upgrade.

Learn more: Increase efficiency and yields with IF/VF radial tires.

3. Maximize Efficiency in the Field and Down the Road with a Central Tire Inflation System

When you equip your tractor with a central tire inflation system, you’ll discover additional performance because you’re able to set the ideal tire air pressure for every situation. Your tractor lives in two worlds: the road and the field. If you’ll remember, most tire manufacturers recommend staying below 15 PSI in the field. Run down the road with tires at this pressure, however, and you’ll slash your tires’ life, burn extra fuel, and deal with mushy handling. On the road, you want your tires as firm as possible. 

Your tires aren’t optimized for anything if you choose a compromise pressure between the ideal field and road PSI.

According to Michelin, the owner of PTG Central Tire Inflation Systems, a system can deliver:

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Installing a PTG central tire inflation system on your tractor will finally put you in complete control of your tires’ air pressure—and tractor’s performance—in every situation you’ll face.

Learn More: Boost fuel economy, traction, and flotation with a central tire inflation system.

4. Set Correct Ballast and Weight Distribution

Remember that your goal is to find a good balance between traction and flotation to optimize your tractor’s fuel efficiency and other performance aspects. A good way to gauge this balance is by wheel slip percentage. The ideal amount of wheel slip is between 8 and 12 percent for a 4WD tractor and 10 and 15 percent for a 2WD tractor. 

Learn More: Discover if your tractor’s slip percentage is optimized.

In order to dial in your slip rate, your tractor will need to run with the correct amount of ballast. For a 4WD tractor, your target weight is generally 95–110 pounds of ballast per engine horsepower for ag operations. For example, if you have a 500 hp 4WD tractor, you’ll want its weight to be between 47,500 and 60,000 pounds. 

You also need to make sure that the weight is distributed correctly by operation type and implement.

Ideally, it’s best to use metal weights whenever possible. Liquid ballast works, especially when you want to ballast a tractor for stability reasons, but it will impair a tire’s ability to flex. Plus—weights are much easier to take on and off when you need to adjust the weight of your tractor for different operations. (Wrangling ballast-filled tires to mount or dismount them can be dangerous.) Remember: you don’t want to load your tractor to its maximum weight for every application. Sure, you’ll have low wheel slip, but you’ll also be burning more fuel just to climb out of your ruts all day.

5. Operate Efficiently

To get the most work out of your tractor’s engine for the amount of fuel consumed, the engine should operate at or near its maximum load. If a particular operation doesn’t require your tractor’s ultimate amount of grunt, you can gear up and throttle back to save fuel. According to Michigan State University Extension, when used correctly, working in a higher gear at a lower throttle setting for the same field speed can increase fuel efficiency by 13% to 20%. 

However, it’s best  not to lug the engine. Keep an eye on your tractor’s power meter display as you play around with gear and throttle settings. If your tractor isn’t equipped with one, try this simple test instead: Increase the throttle as you’re moving along at your higher gear/lower throttle setting. If the engine speed advances as normal, you’re good to go. If engine RPMs take a moment to ramp up, you’ll probably want to go back to your original gear/engine speed setting for the application at hand. 

Don’t Neglect Basic Maintenance

You probably have this one covered already, but since we’re close to spring planting, now is a good time for a reminder: 

• Check your tire pressure with a gauge often. Are your pressures set correctly?
• Replace fuel filters at intervals recommended by your tractor or engine’s manual. 
• Replace (or at least blow out) your air filters. 
• Keep your radiator screen free of debris.

Want to Boost Your Fuel Economy? Pay Attention to Your Tires.

Because tires are your tractor’s only link to the ground, they play a big part in your machine’s efficiency (or inefficiency). Unsatisfied with your tractor’s performance? Give NTS Tire Supply a call and talk with one of our tire experts. Would swapping skinny duals for larger tires pay? How many dollars could a central tire inflation system return to your operation? Is your tractor ballasted correctly and are your tires set to the correct tire pressures? Our tire experts can answer all your questions. And NTS Tire Supply will help you get the right tires and wheels on all your equipment to drive your farm forward.