In the United States, the Office of Vehicle Safety Compliance, a component of the Department of Transportation, is one of the agencies tasked to enforce the Federal Motor Vehicle Safety Standard (FMVSS).
P indicates that the tire is engineered to TRA standards, and absence of a letter indicates that the tire is engineered to ETRTO standards.
The testing method consists of pressing the tire against a large diameter metal drum to reflect its appropriate load, and run at ever increasing speeds in 10 km/h (6.2 mph) steps in 10 minute increments until the tire's required speed has been met.
Prior to 1991, tire speed ratings were shown inside the tire size, before the "R" construction type.
An example: a P205/50R15 Standard Load tire has a load index of 84 and a load rating of 505 kg (1,113 lb) at 35 psi (240 k Pa).
As an example, if a tire size has two sets of numbers (6-12, 5.00-15, 11.2-24), then the first number (5.00-15) is the approximate width in inches, and the second number (5.00-15) is the rim diameter in inches.I am A simple woman that wants a simple life..looking for a man in a similar way..his age doesnt matter as long as he knows how to fix a broken i am a single i am looking for a man that will truly acce..The code has grown in complexity over the years, as is evident from the mix of SI and imperial units, and ad-hoc extensions to lettering and numbering schemes.New automotive tires frequently have ratings for traction, treadwear, and temperature resistance (collectively known as The Uniform Tire Quality Grade (UTQG) ratings).While all ETRTO tires of the same load index will have the same maximum load, P-Metric tires with the same load index may have different load capacities depending on the tire size.The TRA Inflation Tables must always be consulted when comparing the load capacity of P-Metric tires; the Load Index alone is not sufficient.ETRTO produces a Standards Manual (current edition 2010), which contains a number of specifications and tables.The load index table (2010 page G7) lists the Load index from 0–45 kg (0–99 lb) to 279–136,000 kg (615–299,829 lb) (although it appears to relate to an inflation pressure of 42 psi (290 k Pa) it doesn't specify, but see Load Inflation Table).But it’s a setup, because what the guys don’t seem to realize is that she is a professional stunt driver — and they are in for a real shock as she spins, drifts and tears around a parking lot. Automobile tires are described by an alphanumeric tire code (in American English and Canadian English) or tyre code (in British English, Australian English and others), which is generally molded (or moulded) into the sidewall of the tire.