Bias Ply vs. Radial Truck Tires

The question of bias ply vs. radial truck tires actually has its roots in mid-twentieth-century tire development and the technological breakthrough that was the radial tire.

Radial vs. Bias Ply
Radial vs. Bias Ply

Let’s get into some basic definitions first, which will help illuminate the discussion, and well, why in the twenty-first-century, the debate is all but closed – nearly every modern truck tire is of the radial variety.

What is a bias ply tire?

The earliest forms of automotive tires were all bias ply. Think Ford’s Model T and the like – they were all shod with bias ply tires.

The term “bias ply” is a reference to the tire’s type of construction. Underneath a tire’s external tread are many layers of construction materials, including “plies” that serve as the structural foundation of the tire.

Layers of plies give the tire its strength and support
Layers of plies give the tire its strength and support

On a bias ply tire, the plies are placed in a layered, angled, overlapping/crisscross pattern and extend throughout the entire tire. So to put the bias ply concept into tire tour guide type terms, you could think of each ply as starting at one bead, heading “up” the tire sidewall, across the center/crown section of the tire (the part that makes contact with the road), and then “down” the opposite tire sidewall to the opposite bead in 40-60-degrees of the tire’s direction of travel.

What is a radial tire?

Invented in 1946 by Michelin, the radial tire also uses plies as a structural foundation of the tire. However, unlike with the bias ply tire, which overlaps and weaves the plies, the plies of a radial tire are “stacked” across the center/crown section, and specifically, these same plies don’t extend down the tire sidewalls to the bead in 90-degrees of the tire’s direction of travel.

The separation of crown and sidewall ply elements permits these two key areas of the tire to function independently. Gone is the interconnectedness of the bias ply tire that means the tire always functions as one unit.

How radial works
How radial works

The advantages of radial tire construction include:

  1. Improved comfort. Just about every road bump you’ve ever experienced was minimized thanks to radial tire technology. With plies not extending across and down the entire tire, the tire sidewall is permitted to flex and absorb impact independently without transferring that impact through the entire (interconnected) structure of the tire.
  2. (With some exceptions – bias ply tires can be an advantage over particularly rough terrain at slow speeds.)

  3. Superior heat management and dissipation. The radial tire improves tire tread life due to superior heat management.

Tires develop heat while under load/in use, and more heat, as in the case of a bias ply tire means higher tread wear.

  1. Excellent tire flexibility and road surface interaction. It’s easy to think of tires as fixed, rigid objects, but in fact, there’s a high degree of ongoing interactivity between the tire and road surface as the tire rolls. Everything from routine vehicle maneuvering to water evacuation on wet roads, to traction in off-road conditions is aided by tire malleability.

Bias ply tires were particularly limited in this department because of just how stiff the whole tire structure was.

  1. Superior handling. Radial tires create a better, more consistent tread contact patch when cornering and under load. The end result is a more responsive, better-controlled vehicle.

Simply put, a vehicle with radial tires is just plain easier to drive and control, especially in the case of emergency maneuvering.

  1. Lower rolling resistance. Radial tires achieve superior fuel economy thanks to lower rolling resistance, and again, less heat buildup.

The advantages of radial tires were so overwhelming that it quickly became the predominant form of tire and grew in popularity in the 1970s.

A 1968 Consumer Reports study comprehensively documented the advantages of the radial tire and sealed the deal. In 1970 Ford fitted radial tires as original equipment (OE) for the first time on a production vehicle.

Are there any advantages to bias ply tires?

Yes, in certain applications. Bias ply advantages include:

  • Less complicated tire construction and, therefore, typically lower cost
  • The stiffer sidewall can be an advantage in certain applications, e.g., as trailer tires where a bias ply tire may deliver less sway and bounce than a radial
  • Rugged design and sidewall puncture resistance (some agricultural tires are bias ply)

But today, bias ply tires on automobiles have mostly been relegated to classic car/truck restoration projects and car shows. If the goal is to replicate the true classic look, then bias ply tires achieve that best.

When it comes to your truck though, radial tires are almost certainly the ticket. There are a few modern manufacturers of bias ply truck tires, but almost no matter where and how you drive, you’ll be at an advantage with radial options.

Every major truck tire category – mud-terrain, all-terrain, and all-season – is dominated by radial tires.

Have further questions on this topic, or need some help tracking down the right tires for your truck? We can help narrow your search. Gives us a call at 866-961-8668.

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