What is the 91W on a tire?
While a Z-speed rating still often appears in the tire size designation of these tires, such as 225/50ZR16 91W, the Z in the size signifies a maximum speed capability in excess of 149 mph, 240 km/h; the W in the service description indicates the tire’s 168 mph, 270 km/h maximum speed. Z-rated high-performance tyres are rated for speeds in excess of 149mph. Confusingly, W-rated tyres are rated at a higher speed in excess of 168mph. Y-rated tyres are rated in excess of 186mph.You can fit tyres with a higher speed rating than recommended by your vehicle’s manufacturer.Essentially, it means that your tyres will be able to handle a specific maximum speed while carrying a load. Typically, tyres with a W rating can handle a maximum speed of 168 mph.Using tyres with different speed ratings can also cause uneven wear and tear on the tyres, leading to a shorter lifespan and potentially compromising the safety of the vehicle. The only exception to this is a winter tyre.But the development of faster vehicles brought us two new speed ratings: W and Y-rated tires, both of which are rated for higher speeds than the Z despite their earlier place in the alphabet. These speed ratings provide a more precise indicator of a high-performance tire’s speed over 149MPH.
What does the 91 H mean on a tire?
A: Hello, the number stands for the load index (91 means tires tested up to 1358lbs), and the speed index (H rated tires tested up to 130mph, T tested up to 118mph). The speed rating on tyres usually comes at the end, after the load rating. How to read a tyre speed rating. For example, 205/55 R16 91W denotes a W speed rating, which means the tyre can handle speeds of up to 168mph (assuming it is not overloaded).The primary distinction between 91w and 95w tyres lies in their load-bearing capacity. A 91w tyre has a maximum load of 615kg, whereas a 95w tyre can bear up to 690kg. The ‘w’ denotes the tyre’s maximum speed capability of 270 km/h.Some manufacturers will insert a “Z” in the middle of the tire size description (right after the aspect ratio) when the tire is rated at “W” or “Y. And if a tire is rated in excess of 186 mph (300 kph), manufacturer’s usually will list a “Z” within the size description, per industry standards.The higher rated tyres, specifically W rated tyres, tend to be required on high-performance sports cars. So, what does tyre rating W mean? It means that you have a car that is capable of driving safely at high speeds up to 168 mph.
What does 225-45 R17 mean on tyres?
R17 on UK car tyres indicates a 225mm wide tyre with a 45% aspect ratio (sidewall height) designed for 17-inch wheels, using radial (R) construction. This tyre size is common on popular UK models like the Volkswagen Golf, Ford Focus, and BMW 1 Series. Section Width in millimeters. Aspect Ratio. R – Designates the tire has radial construction. Wheel Diameter. Load Index.Understanding Tire Sizes 225 or 235: This is the tread width in millimeters. A 235 tire is about 10mm wider than a 225.
What is a 91 rating tyre?
A tyre with a load index of 91, for example, can hold a maximum load of 615 kg at the correct PSI up to its rated speed. Yes, the 91W / 95W are the load and speed rating. It’s always* safe to go up from your vehicles standard spec, but not always to go down. A higher rating should not be a problem, but going lower than you need is a risk.