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Tractor Tire Types & Sizes Explained

Tractor Tire Types & Sizes Explained

Tractor tires are designed with specificity because they have to perform on loose soil and soft field surfaces, without damaging your soil or crops. And because each tractor and plot of land is different, it’s important to look at all of your options and pick the right tires for you! 

In this blog post, we’ll help you make some of the choices it takes to choose the right tire for your tractor.

 

- Tractor Tire Construction: Bias Ply vs. Radial
- Tractor Tire Tread Design: Lugs vs. Ribs
- Tractor Tires: Tube vs. Tubeless
- Tractor Tires: Understanding Tire Sizes
- Best Tractor Tires

 

Tractor Tire Construction: Bias Ply vs. Radial

Both bias-ply and radial tires are essential in the agricultural tire market. While radial tires bring many important benefits to the farm, such as less soil compaction and more traction, there are a few reasons that bias tires continue to hold a share of the market. 

In order to make the best decision for your next farm tire purchase, you need to understand the differences between bias and radial tires and how their attributes affect their performance in the field (and on the road).

 

Bias Ply Tractor Tires

Bias ply tractor tires are constructed using multiple plies of rubber in a diagonal pattern from bead to bead. Because of this method, the tread and sidewall of a bias tire function as one unit. This creates a strong and stiff sidewall that can prevent any damage from stumps and rocks. And because they’re stiff, bias tires can offer excellent stability on hilly terrain. 

However, a bias tire’s stiff construction can cause a rough ride for the tractor operator. And when the sidewall of the tire flexes, so does the tread. This tread manipulation may lead to a smaller or distorted footprint, which can increase wheel slip, reduce traction, and result in more compaction in your fields.

 

Bias Tire Advantages: 

- Lower initial purchase price
- Stiff sidewall prevents swaying on hillsides
- Durable sidewalls protect against punctures
- A rounded tread profile that is easier on turf

Bias Tire Drawbacks:

- Rough ride for the tractor operator
- Increased compaction and rutting/sinking due to small footprints
- Higher fuel consumption due to increased rutting/sinking 
- Lower load capacities compared to modern radials
- Quick wear due to heat buildup with extended road travel

 

Radial Tractor Tires

Two-part construction is what sets radials apart from bias tires. The cord plies are placed at 90 degrees to the direction of travel, and the under-tread is wrapped around the circumference of the tire using radial belts of steel or fabric. 

With a radial tire, sidewall flex doesn’t manipulate the tread, allowing for more even wear. This is why the tread on a radial tire can last 2 to 3 times longer than a bias tire’s tread.

Unlike bias ply tires, a radial tire’s construction creates a larger, more uniform footprint. As you load up a radial tire, its footprint will actually grow longer, not wider. This provides better traction and efficiency. The larger footprint also limits soil compaction, which can decrease your yields. 

 

Radial Tire Advantages:

- Higher load capacities
- Less soil compaction (when properly inflated)
- Longer-lasting tread and more durability due to better heat dissipation
- Lower cost per hour due to longer-lasting tread
- Better fuel economy thanks to increased traction and decreased slip
- More comfortable ride for the tractor operator 
- More secure handling for the tractor operator 

Radial Tire Drawbacks:

​​​​​​​- More expensive than bias tires initially

 

Radial Tires: The Best Option for Farm Performance

You will want to mount radial tires on any tractor that tracks across your fields. You might be able to get by with bias tires on your smaller chore tractors, but when it comes to planting, spraying, harvesting, and tillage, you should be driving on a reliable set of radial tires.

 

Lug tractor tire tread impressions in the field dirt.

Tractor Tire Tread Design: Lugs vs. Ribs

A tractor tire's tread design is considered just as important as its construction. Agricultural tractor tires usually come with one of two tread pattern types: directional lug or raised rib.

Lugs

A tractor tire with an interwoven tread design usually also incorporates traction-grabbing lugs. The deep angles of the lugs have deep penetrating abilities, providing increased traction and self-cleaning capability. This also increases their tread life. Their opposing angles help to grip the ground with additional biting edges.

 

Lug Tread Design Advantages:

​​​​​​​- More stability and brake power
- Stronger traction 
​​​​​​​- Increased tread life
​​​​​​​- Good soft and hard terrain traction

Lug Tread Design Drawbacks: 

​​​​​​​- Less fuel-efficient than rib tread
​​​​​​​​​​​​​​- Less driving stability than rib tread
​​​​​​​- Lateral grooves make for a rougher and longer ride

 

Ribs

The ribbed tread improves the tractor tire's surface contact. Multiple or single-rib tires provide the extra steering control necessary for slippery field terrains. In addition, their consistent contact with the driving surface also offers a comfortable, quieter ride.

 

Ribbed Tread Design Advantages:

​​​​​​​- Even tread wear 
​​​​​​​- Increased fuel efficiency
​​​​​​​- Quieter and quicker ride
​​​​​​​- More driving stability
​​​​​​​- Decreased rolling resistance
​​​​​​​- Good for both wet and dry traction

Ribbed Tread Design Drawbacks:

​​​​​​​- Less traction than lug tread
- Less brake power than lug tread

 

The Best Option for Farm Performance: It Depends on Your Specific Tractor and Land Conditions

Lug tires are the ideal option if you are looking for maximum traction in soft and loose soil conditions (i.e. muddy fields, sandy terrain, or wet land). They work best for applications such as plowing, tilling, cultivating, and harvesting.

In contrast, rib tires are ideal if you are looking for stability and less soil disturbance on hard surfaces (i.e. roads, concrete, or compacted soils). They work best for applications such as transportation, towing, or light tillage.
Depending on your tractor, soil, and terrain type, one tread type might be better suited for you than the other. Both lug and rib treads have important and necessary characteristics. If you are struggling to decide what would be best for you, consult with a qualified farm tire specialist. We can help you select the best tire for your needs!

 

Dirty lug tread tractor tires working in the freshly planted field.

Tractor Tires: Tube vs. Tubeless

These days, more tubeless tires are manufactured than tubed. However, this doesn’t necessarily mean that tubed tires are being left behind entirely. You can find both tubed and tubeless tires on the agricultural tire market, but which option is the best for your tractor?

  

Tubed Tires

A tubed tire includes a tube filled with air that’s fitted between the rim and the tire itself. The valve of the tube is attached to the rim and is used to inflate the tire. So, when a sharp object pierces the tire, the air in the tube will find its way out fast. This instant release of air can cause the tire to burst.

 

Tubed Tire Advantages: 

- You can use an inner tube to fix a slow or hard-to-find leak 
- Initially less expensive than tubeless tires
- Some farmers believe tube tires are best when working steep hillsides

Tubed Tire Drawbacks: 

- Will go flat quickly (if not immediately) when punctured
- Not a good fit with modern radial tires
- Inner tube is easily pinched, which can cause a flat tire
- Added tire repairs and maintenance because of the inner tube

 

Tubeless Tires

A tubeless tire is similar to tubed tires, but they don’t have the inner tube to hold the pressurized air. Instead, the rim of the wheel and the tire form an air container. The inner wall of the tire is lined with an airtight membrane to seal the air, which is called the inner liner. 

If a sharp object punctures a tubeless tire, the air escapes slowly only through this hole. As a result, the tire loses air slowly, giving the driver enough time to fix it, before it bursts.

 

Tubeless Tire Advantages: 

- Doesn’t require a separate air tube 
- Better operational efficiency
- Excellent heat emission
- Rate of deflation is slow, uniform, and safer
- Last longer and are more durable 
- Weigh less, reducing the tractor’s unsprung weight and improving performance, maneuverability, and handling
- You can ride on tubeless tires at low pressures as you improve traction off-road without the risk of pinch-punctures

Tubeless Tire Drawbacks: 

​​​​​​​- Initially more expensive
​​​​​​​- ​​​​​​​More complicated to install than tubed tires
​​​​​​​- Poor assembly can make tubeless tires seem inefficient
​​​​​​​- Rocks and obstacles can damage the rim flange resulting in air leakage
- The tire bead can separate from the rim due to a sudden impact or extreme cornering force

 

Tubeless Tires: The Best Option for Farm Performance

The sudden deflation of a tubed tractor tire is not only a pain because you’re stuck, but is also unsafe in many situations. Depending on how fast you’re driving, there’s the potential for accidents and even injuries. 

Because tubeless tires deflate at a much slower rate, you’ll have the ability to make it back safely  without a drastic impact if you puncture your tire on the field. That added safety grants you peace of mind each time you climb onto your tractor.

So, unless you’re outfitting vintage equipment, it’s best to go tubeless 99% of the time. With modern tractor tires, tubed tires are more useful for recreation than fieldwork.

 

Tractor Tires: Understanding Tire Sizes

Understanding tractor tires may seem confusing, but we promise it’s easier than you think! You’ll be able to find all the information you need on your tire’s sidewall. There are two types of sizing to keep in mind: conventional and metric.

 

How To Read Tractor Tire Size

Conventional sizing  

Conventional sizing is probably the most common size marking system in use today. Here are a few examples of what you might find on your tractor tire sidewall: 7.50-16, 11L-15, 13.6-28, and 18.4R38. 

The first number is the nominal cross-section in inches, which is followed by a dash (-) to indicate bias construction or an “R” to indicate radial construction. The number after the dash or “R” is the nominal rim diameter. 

 

Metric sizing 

This new tire marking system has the approval of the International Standards Organization (ISO). Here are a few examples of this type: 320/90R46 and 710/70R38. 

The number before the “/” is the nominal cross-section in millimeters. After the “/” is the aspect ratio, “R” indicates radial construction (“D” for bias or diagonal), and then the nominal rim diameter.

 

Wonderland Tire's expert agriculture tire technician replacing a large tractor tire on the field.

Best Tractor Tires 

At Wonderland Tire, we only want what’s best for your tractor and ultimately your fields. More often than not tubeless, radial tires will be the wisest and safest option on the market. And when it comes to tread, it will depend on the type of tractor and land you are working with. 
Have any questions or want to learn more about what tractor tires will work best for you? Contact us and we will be sure to answer all of your questions!

 

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