Radials vs Bias Ply: Choosing the Right Tires Makes All the Difference

Tires are on the front line when it comes to a vehicle’s motion, meaning they see some pretty intense abuse. For this reason, it seems to go without saying that it’s really important to pick the best option for your vehicle application. In the world of drag racing, you’ll find a lot of guys running both radial and bias ply tires. In which case, doesn’t this dispute one being better than another? Not really because it’s situational. Choosing the right tire comes down to a few factors, and understanding the difference between the two is an important part of the decision.

Bias Ply vs Radial

Bias ply tires are an older technology that became known in drag racing as “slicks” during the early days of performance competitions. Often described as “balloon tires” because of their air-filled rubber construction, bias ply tires secure their internal reinforcement from overlapping plies of nylon cords. These cords crisscross from bead to bead inside the tire, to give the sidewall support. The advantage of these tires is a soft flexibility. After all, the classic sidewall wrinkle is notoriously associated with slicks.

Radials are born from newer technology and are growing in popularity, primarily for both their track and street performance capabilities. Radials also use nylon reinforcement but instead of crisscrossing in the tire, the cords run across from bead to bead. Additionally, cord or steel belts are used to run the length of the tire’s contact patch. These belts help keep both the contact area and the sidewall stable, resulting in stiffer and more stable tires. They are also praised for offering longer tread life and better fuel economy.

Construction vs Performance

Construction characteristics go a long way, but real-world performance really does the talking here. The softer design of a slick allows for higher RPM’s when launching. The sidewalls give and absorb a lot of the shock that could otherwise damage moving parts, like the differential or transmission. However, they do tend to wobble. And the slightest jerk of the wheel can mean the driver will be fighting to keep the car straight. One thing to keep in mind is that both styles of tire can be constructed of the same compound. It’s only the structural support that differs. Radials do tend to be stiffer and bite into the track differently. There’s not as much give in the sidewall, so they work more to grab-and-go. Additionally, since they are a lot more stable, they will help with keeping the car straight.

John Potucek, a lifelong drag racer and trusted employee at Keystone Automotive, offered his two cents on the matter and really helps give definition to making the right selection.

“Stick cars tend to lean towards a slick, as the sidewall handles the initial shock better. Auto cars can get away with a drag radial, assuming the surface is prepped somewhat … If you run a slick [bias ply tire] out back, you should really be matching it to a bias ply tire up front. That’s another nice thing about running a drag radial out back—you can run a radial up front. Sure you can mix-match radials and bias ply, but it’s going to handle less-than-ideal.”

Consult a Pro

Ultimately, it isn’t as clean cut as one style being better than the other. As Potucek mentioned, stick drivers usually do lean on the give of a bias ply. But in our conversation, he also made it known that the tires are only a single part of the equation. Aside from road conditions and driving habits, the entire vehicle’s setup will have a bearing on tire performance. For example, suspension will play a factor in dictating which tires will work the best. Because there are so many different circumstances affecting tire selection, it’s impossible to tell readers exactly what to choose. A sure bet when selecting tires is to speak with qualified service professionals and use their expertise to your advantage. Their industry knowledge can help you decide what’s best for your unique ride.

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