Radial Vs Bias Ply Tires (What is the Difference?)
Posted by Priority Tire on Sep 16th 2022
The radial tire vs bias ply debate has been talked about since radial tires appeared on the market. Are radial tires really that much better than bias models?
In today's society, passenger vehicles demand a lot from their tires - performance, traction, handling, fuel economy, service life, comfort, etc. are all requirements. But, which tire construction can offer all of these?
What is the difference between radial and bias ply tires? Read on and find out!
What are Bias Ply Tires?
Bias ply tires, or tires that feature a bias ply placement, have the plies in their internal structure placed diagonally. This diagonal pattern is angled at 30-40 degrees to the center line.
Due to the crisscross pattern of bias ply tire models, they feature thicker sidewalls and narrow footprints. This tire construction type offers better load durability. However, since their sidewalls don't flex, their tread life is affected as the footprint deforms instead.
So, what is a bias ply tire used for?
To put it simply bias ply tires offer better load capacity, which makes them perfect for heavy-duty applications. But, let's talk about their pros and cons in the next section.
The Advantages of Using Bias Ply vs Radial Tires
Both radial tires vs bias ply models come with advantages and disadvantages. If it wasn't like that, we would not need to write this blog post!
Therefore, when talking about what these tires provide, the radial vs bias tires debate needs to be scrutinized a bit more. First, let's talk about bias-ply tire models and what they have to offer!
The main difference between bias and radial tires is the placement of the tire plies. How the tire cord structure is set up will greatly affect the tire's performance, durability, and functionality. This is true for both radial and bias tires.
However, a bias-ply tire construction ensures the following advantages:
- Lower prices
- Sturdier sidewalls
- Damage resistance
They Usually Cost Less
When comparing prices of bias vs radial tire models, a bias ply tire will always cost less. This is due to the lower manufacturing cost tire brands need to spend to create one bias ply tire, compared to a radial tire.
However, this comes at a price. The treadwear rating of bias models is not the best and their tread life won't last as long as radials'.
Bias Tires Come with a Stiffer Sidewall
Due to the bias ply placement, these tires feature stiffer sidewalls. This makes them perfect to perform as a heavy-duty tire, and even ensures its trailer applications.
For this reason, many construction trucks and trailers are equipped with a bias-ply tire set, as these tires are able to provide the necessary load durability. Stiffer sidewalls ensure straight-line stability, preventing trailer swaying.
As the construction of these specialty tires does not deform, they are capable of handling heavier loads with ease.
Outstanding Sidewall Puncture Resistance
Nowadays, bias plies are considered unique tires, yet they are still used. Most specialty tire sets are manufactured with bias-ply cord placements, which are used for heavy-duty machinery. This makes these tires perfect to be created in big tire sizes.
A high flotation tire, a construction tire, and even agricultural tires must offer damage resistance. This protects their structure from external damage throughout their performance, which is especially important for industrial and flotation tires.
The Problem with Bias Ply Tires
Now let's take a look at the issues of a bias-ply tire set.
While the bias-ply structure is perfect for heavy-duty applications, it also comes with its downsides. The main issue with these models (whether they are industrial or trailer tires) is caused by their structure.
The interconnecting plies create a stiff sidewall, but they do not provide the same support to the tread area. This results in an uneven surface contact area, placing different degrees of driving pressure onto various tread areas, which leads to different problems.
First, it shortens the tread life. The stiff structure causes pressure build-up along the tread area, accelerating tread wear. On the other hand, the tread center will bulge out slightly due to load pressure, resulting in irregular wear. This combination greatly decreases a bias-ply tire's service life.
The other issue is the wandering feeling drivers have, which can reduce controllability. The bias structure makes the footprint follow cracks in the pavement while the tires are in motion. This requires drivers to pay more attention to the vehicle and driving conditions to maintain control.
Here's Why it Pays Off to Buy Radial Ply Tires
We talked about one side of the bias vs radial tires debate. Let's give the same attention to radial tires.
What is a radial tire?
Radial tires or standard tires (as they are now known) feature structures where the plies are added at 90-degree angles from one bead to the other. This does not create the known crisscross pattern of bias-ply tires.
The radial construction allows minimal sidewall flexing, which improves the passenger car's performance. The main reason for this is the heat resistance of radial tires. But, radials also offer other advantages:
- Damage resistance
- Enhanced traction
- Comfortable drive
- Resistance to heat build-up
- Better fuel economy
- Increased controllability
When it comes to bias-ply tires vs radial models, the difference is overwhelming. Most advantages are in favor of radial tires. But, why? Let's take a look.
Cut and Puncture Resistance
Radial ply cords protect the tire's tread area during its performance. These tire models offer better resistance to punctures and cuts that happen during the tire's regular use.
This is thanks to the ply placement of radial tires. A radial tire structure consists of both rubber-coated radial plies and steel belts that protect the tread area and casing from external damage.
Major Impact on Traction
The flexibility of radial tire sidewalls ensures better traction. This structure makes sure the tire's entire footprint is in contact with the driving surface, generating traction in its intended conditions.
The wider footprint and stabilized tread elements optimize pressure distribution, preventing pressure build-up on certain tread areas. Not only does this increase tread life, but it also optimizes the tire's performance and road grip.
Smooth and Comfortable Ride
The stable footprint and close road contact of a radial tire guarantee better driving comfort. This is thanks to the reinforced stability of the radial tire's structure, which minimizes road vibrations and noise levels.
When it comes to the comfort levels of radial vs non-radial tires, the difference is easily noticeable. Radial models are able to decrease both vibrations and noise generated while the tires are in motion.
Resistance to Heat Build-up
Often a popped tire is the result of heat accumulation, which ruins the tire's integrity. Radial tires help to minimize this occurrence as they are designed to keep cool for longer periods of time.
The stronger structure does not allow heat from building up on sensitive tread areas. Tire temperatures can be dangerous, as they can cause blowouts if drivers are not careful. Equip your vehicle with a radial tire set to minimize the possibility of this happening.
Fuel Efficiency and Longevity
Another important feature of a radial tire structure is that it offers lower rolling resistance. The rolling resistance is the pressure that determines the vehicle's fuel intake. By reducing it, fuel consumption and CO2 emission levels are also decreased. This significantly boosts the tire's fuel economy.
Additionally, along with the footprint's stability, lower rolling resistance also helps prevent premature and irregular wear. As they work together and prevent pressure accumulation on sensitive tread areas, the radial tire can easily combat uneven wear.
For these reasons, between bias-ply vs radial tires, radial tire models are more economic and cost-efficient.
Better Handling and Overall Flexibility
Again, the slight flexibility of radial sidewalls boosts controllability. The sidewalls and wider footprints are able to separately function, which optimizes the road contact to boost steering responsiveness and driving stability. This does not matter if we are talking about performance tires or truck tires.
Furthermore, the optimized road contact patch upgrades the tire's maneuvering capabilities as well. Cornering and braking are enhanced with consistent road contact, even when it comes to bigger tires.
But, but... Bias Tires Look so Good on Vintage Cars (Sob)
Yes, we agree - muscle cars look best with aesthetic tires!
However, in order to get that "look", you don't need to sacrifice ride quality.
A bias tire vs radial tire set will let the muscle car perform differently. The problem is that even modern bias-ply tires for vintage cars do not offer the necessary quality and performance.
Yet, the tire market is vast. Finding a specialty tire set, with beautiful white sidewalls, is not that hard.
Designed for 70's American Cars
Radial tires were not always the norm. Up until the 1970s, bias-ply tires ruled the market. Furthermore, these tires featured the well-known wide white sidewalls that look phenomenal on vintage muscle cars.
However, a demand for more durable tires set bias tire production back and pushed radial models into the limelight. This led to bias-ply passenger car tires becoming almost extinct. They are definitely endangered!
Still, many vintage vehicle owners want the authentic look of a bias-ply tire set. They are in luck!
The specialty tire market still has tire manufacturers who supply such products. These modern bias tires are designed and created with modern rubber materials, more durable cords, and state-of-the-art technologies to ensure their longevity.
Who are these brands? Well, Firestone, BFGoodrich, and U.S. Royal are the tire brands that come to mind.
Calm Down, Bias-Looking Radial Tires are Here
Yet, there is another way to make vintage cars look authentic!
Some tire brands specialize in creating tires that provide the best of both worlds. They provide the advantages of both bias-ply and radial structures. Such tire manufacturers create tires that offer the special look of bias models, without their downsides.
These tires ensure the durability and handling safety necessary for everyday driving, without ruining the vehicle's aesthetic appeal. Products such as these are DOT approved for highway use.
The only negative we can find with these combination tires is their price. Due to them being classified as specialty tires, buyers will need to dig deeper into their wallets to pay for a set.
Radial vs Bias Ply Tires in Construction
One of the categories, where bias tires dominate in the 21st century, is construction. A truck with big tires, which is used for transport, earth moving, or various other construction applications, needs the durability a bias structure offers.
Therefore, in construction, the radial vs bias tire debate is in favor of bias tires.
That is not to say that radial tires are not manufactured for such applications... there are just more bias-ply tires designed and produced for these vehicles.
Bias-ply tires do not deform under larger loads and offer better flotation capabilities. Two characteristics are crucial for work-site performance. So, equip your construction vehicles with stronger bias models.
How to Tell if a Tire is Radial or Bias?
The easiest way to tell if a tire is radial- or bias-ply is to look at the tire size. If they are radial tires, the tire sizes will have an R between the aspect ratio and rim diameter numbers. However, when it comes to bias ply tires, their tire size only has a hyphen (-) between those numbers.
What does Tire Ply Mean?
Plies are the internal layers that create the tire construction. Depending on the number of plies a tire has in its structure, the tire ply rating will vary. These plies determine load and driving durability, as they are responsible for maintaining the optimal shape.
How to Tell What Ply a Tire is?
The ply rating on tires is located on their sidewall. Most tires for passenger cars feature a 4-ply rating, while light and commercial truck tires offer better durability. Heavy-duty truck tires are usually available with ply ratings starting at 10 and going up.
What is the Load Index on Tires?
The load index on tires shows the load durability of each individual tire. This is a number system that corresponds with the lbs one tire construction can handle. The load capacity of each tire should not be exceeded in order to ensure the tire's safer driving experience.