Two kinds of tires for specialized performance
Due to their soft sidewalls, the crowns of radial tires stick to the road on contact. Their footprint, shorter but wider than that of a bias tire, provides added grip when leaning in heavily on corners. The pressure of the air in contact with the tire surface is distributed more effectively with radial tires, which results in more even tread wear over time.
Radial tires also provide greater comfort at higher speeds, once again as a result of their soft sidewalls, which absorb the impact of imperfections on the road surface. On the other hand, bias tires are able to carry a greater weight because their sidewalls are more rigid. At high speeds, bias tires can become so deformed that their performance is affected. Ultimately, bias tires are suitable for vehicles travelling at moderate speeds, with small to medium-sized engines and flexible chassis. They are also suited to heavy or heavily loaded motorcycles. Radial tires are needed for more powerful vehicles with very rigid chassis and for more sporty purposes. They allow you to reach ZR speed ratings, above 241 km/h.
FAQ
Read our Frequently Asked Questions.
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The difference is in how the internal cord structure is built. Bias (diagonal) tires: cords run diagonally across the tire at angles less than 65° to the tread centerline, creating a criss-cross pattern throughout—the sidewall and crown have similar mechanical properties. Radial tires: cords run perpendicular (90°) to the tread centerline, and a separate belt reinforces the crown. The result: the crown and sidewall have distinct, independent characteristics—the sidewall can flex while the crown remains rigid, which is the key to radial tires' performance advantages.
Larger, more stable contact patch: soft sidewalls allow the crown to conform to the road at lean, providing more grip when cornering.
More even tread wear: more uniform pressure distribution across the contact patch extends tread life.
Better high-speed comfort: soft sidewalls absorb road imperfections more effectively.
Lower heat generation: less internal friction means cooler running at high speeds.
Better handling feedback: more communicative response to road surface and lean angle changes.
Heavy or heavily loaded motorcycles: bias tires have stiffer sidewalls and can carry greater loads at moderate speeds without deformation.
Low-to-medium performance bikes: bikes with small to medium engines and lower top speeds that never stress a bias tire's performance limitations.
Off-road and rough terrain: bias construction is more robust for impacts from rocks and rough surfaces.
Classic/vintage bikes: many vintage motorcycles were designed for bias tire profiles and geometry—fitting radials can affect handling unpredictably.
Budget-sensitive applications: bias tires are often less expensive for applications where radial performance isn't required.
No—unless explicitly approved by the motorcycle manufacturer. Radial and bias tires have completely different flex characteristics and profiles. Fitting them on the same motorcycle creates a fundamental mismatch: the suspension and frame geometry is tuned for one construction type, and mixing creates unpredictable handling, particularly in mid-corner transitions and during braking. The tires respond differently to the same inputs, which can cause the bike to behave unexpectedly. Always fit matching construction types front and rear.
Your owner's manual specifies the construction type. Alternatively: if the current OE tires have an 'R' in the size designation (e.g., 120/70R17), they're radial. If there's no 'R' (e.g., 120/70-17 or 120/70B17 where B indicates bias-belted), they're bias or bias-belted. Modern sport, sport-touring, and large-capacity motorcycles almost universally use radial tires. Smaller-displacement scooters, cruisers, and vintage bikes often use bias tires. Never guess or substitute—use what the manufacturer specifies.
