Short Answer
Complete Explanation
The sidewall marking “98T” is a standardized code that conveys two key performance characteristics of a tire: its load‑carrying capacity and its maximum safe speed. The numeric part (98) refers to the load index, while the trailing letter (T) designates the speed rating. These values are defined by international standards such as the ECE R30 regulation and the U.S. DOT requirements, and they appear on every passenger‑car tire alongside the DOT identification code.
- Load Index (98):
The number 98 corresponds to a load index of 750 kg (approximately 1 655 lb) per tire, according to standard load‑index tables used worldwide. - Speed Rating (T):
The letter T denotes a maximum continuous speed of 190 km/h (118 mph) for the tire under normal operating conditions. - Combined Marking:
Together, “98T” tells manufacturers, mechanics, and drivers the permissible load and speed limits for that specific tire model. - Regulatory Context:
The marking appears on the sidewall together with the DOT code and is required by both U.S. Department of Transportation (DOT) regulations and United Nations Economic Commission for Europe (ECE) standards.
Common Misconceptions
98T means the tire can only be used on vehicles that weigh exactly 98 kg.
The number 98 is a load index, not the vehicle weight; it specifies the maximum weight each tire can support, which is 750 kg per tire.
The “T” speed rating limits the vehicle to a top speed of 100 km/h.
“T” indicates a maximum sustained speed of 190 km/h; it does not cap the vehicle’s top speed, but exceeding this speed may compromise safety.
FAQ
How do I convert the load index 98 to kilograms?
The load index chart assigns the number 98 to a load capacity of 750 kg (approximately 1 655 lb) per tire when the tire is inflated to the recommended pressure.
Can I use a tire with a 98T marking on a vehicle that requires a higher speed rating?
Using a tire with a lower speed rating than the vehicle’s maximum speed is not recommended. If the vehicle is rated for a speed higher than 190 km/h, a tire with a higher speed rating (e.g., H or V) should be selected.
Is the 98T marking the same for all tire manufacturers?
Yes. The load index and speed rating system is standardized internationally, so a 98T marking has the same load and speed specifications regardless of the brand.
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