Whenever you go tire shopping and come across the different brands, the term “radial tires” will always pop-up. For most passenger vehicles, radial tires is the way to go. The question is, what is on the other side of the tire-type spectrum?
This short article simply differentiates between the two. Bias-ply, or bias, tires are the earlier type of tires. The inner workings of the bias tires are made of nylon or rubber belts that are placed on top of each other in alternating 30 and 45 degree angles. This gives the tires a woven look under the surface. The nylon belts also compose the sidewall, making the sidewall toughness just as much as the tread area. Bias tires were the norm on passenger and industrial vehicles until the late 1970s. Radial tires swooped in with its steel construction during this period of time, and have remained the norm for passenger vehicles.
Radial tires are made of steel belts that are in line with each other and not woven over. The steel dissipated heat better and lasted longer given its nature as a metal. It also allowed for more cushioning since the tread and the sidewall could function independently. With further innovations in radial tire technology, these tires increased fuel efficiency and facilitated the energy transfer from the car to the ground, making a more efficient overall drive. Finally, radial tires were proven to be last longer.
Bias tires nonetheless still have their applications. The distinct appearance of bias-ply tires lends itself to a vintage vibe that vintage car enthusiasts are particular about. Since the belts of bias tires run from the sidewall all the way to the tread, the sidewalls are stiff. This is an advantage for motorcycle riders on thinner tires.
Overall, radial tires will be the norm given their sturdiness, heat dissipation, fuel efficiency, and accessibility. Nonetheless, bias tires are still being produced for different applications, especially heavier, industrial uses.