90/90-21 Street Motorcycle Tires

The 90/90-21 tire size is a widely used specification for street motorcycles, offering a balance of performance and versatility. This numerical combination provides valuable insights into the physical characteristics of the tire, including its width, aspect ratio, and diameter. Understanding these technical details can help you make an informed decision when selecting the right tires for your bike and riding conditions.

Decoding the Dimensions

The 90/90-21 tire size is composed of three distinct numbers:

• 90 refers to the tire’s aspect ratio, which is the ratio of the tire’s sidewall height to the tread width. In this case, the sidewall height is 90% of the tread width.
• 90 represents the tire’s width, measured in millimeters. This means the tire has a width of 90 millimeters.
• 21 denotes the tire’s diameter, measured in inches. This indicates the tire is designed to fit a 21-inch wheel rim.

Factors Influencing Tire Choice

When selecting 90/90-21 street motorcycle tires, several factors come into play, including:

1. Intended Use: Consider whether your bike is primarily used for commuting, touring, or performance riding, as this will influence the optimal tire characteristics.
2. Riding Style: Your riding style, whether aggressive or more relaxed, can affect the desired tire properties such as grip, handling, and durability.
3. Road Conditions: The terrain and weather conditions you typically encounter can impact the choice of tire compounds and tread patterns for optimum performance and safety.
4. Personal Preferences: Your personal preferences, such as ride comfort, noise levels, and overall tire aesthetics, can also play a role in your tire selection.