What Does 91h Mean on Tire Size?
The “91H” on a tire size refers to the load index and speed rating of the tire. The load index of 91 means the tire can support 1,356 pounds at maximum air pressure. The “H” is the speed rating, indicating the tire is safe for speeds up to 130 mph.
Basics of Tire Codes
Before diving into “91H,” it’s essential to understand the basics of tire codes. Tire sizes are usually expressed in a format like “205/55R16 91H.” Each part of this sequence provides specific information about the tire’s dimensions and capabilities.
- 205: This number indicates the tire’s width in millimeters.
- 55: This number represents the aspect ratio, which is the height of the tire’s sidewall as a percentage of its width.
- R16: This indicates the tire’s construction type (“R” for radial) and the diameter of the wheel in inches that the tire fits.
Now, let’s focus on the “91H” part.
What Does the “91” Mean?
The number “91” in the tire code is the load index. The load index tells you how much weight the tire can safely carry when fully inflated. It’s a numerical code that corresponds to a specific weight capacity.
For instance, a load index of 91 indicates that each tire can support up to 615 kilograms (approximately 1,356 pounds).
To determine the total weight your tires can carry, multiply the load index weight by four (since a car typically has four tires). In this case, a vehicle with tires rated at 91 can carry up to 2,460 kilograms (about 5,424 pounds) in total.
Why Is the Load Index Important?
Understanding the load index is crucial because it affects your vehicle’s safety and performance. If you choose a tire with a load index lower than what’s recommended for your vehicle.
The tires could be overloaded, leading to premature wear, reduced handling, and potentially dangerous blowouts. Always ensure the load index of your new tires matches or exceeds the manufacturer’s specifications.
What Does the “H” Mean?
The “H” in the tire size code refers to the speed rating. The speed rating indicates the maximum speed at which the tire can safely operate under its recommended load capacity. This is represented by a letter, with each letter corresponding to a specific speed.
- H: This speed rating means the tire can handle speeds up to 130 miles per hour (210 kilometers per hour).
Why Is the Speed Rating Important?
The speed rating is crucial for maintaining the safety and performance of your vehicle. Even if you never drive at the tire’s maximum speed, the rating also reflects the tire’s overall durability, heat resistance, and ability to maintain performance at higher speeds.
Using a tire with a speed rating lower than what’s recommended could lead to decreased handling performance, especially at highway speeds, and increase the risk of tire failure.
Load Index & Speed Rating
When replacing your tires, it’s essential to match or exceed both the load index and speed rating specified by your vehicle manufacturer. These specifications can typically be found in your vehicle’s owner’s manual or on a sticker inside the driver’s door.
If you frequently carry heavy loads or drive at higher speeds, opting for a tire with a higher load index and speed rating can provide added safety and performance.
However, remember that higher-rated tires might be more expensive and could have a stiffer ride due to their design for increased loads or speeds.
Importance of 91H in Tire Size
The “91H” in your tire size isn’t just a random set of numbers and letters—it’s a crucial code that tells you how much weight your tire can carry and how fast it can go safely.
By understanding what “91H” means, you can make informed decisions when purchasing new tires, ensuring your vehicle remains safe, comfortable, and capable on the road.
Always check your vehicle’s specifications and consult with a tire professional if you’re unsure about the right tires for your needs.
Remember, your tires are the only part of your car that touches the road, so choosing the right ones is essential for a smooth and safe driving experience.
Meet Caitlin McCormack, a Tire Size Expert and Blogger Passionate About Everything Related to Tires. With Years of Experience in the Tire Industry, Caitlin Has Become an Expert in Tire Sizes and Their Impact on Vehicle Performance.