Making sense of those numbers on a tire
I just started shopping for new tires and amconfused by all the numbers used to list each tire. What do the numbers 98V mean? They’re listed right after the P225/60VR16 on the tire I’m considering. — WarrenM.
Good question, Warren. Let’s look at all the numbers you mentioned. P indicates the tire is intended for use on a passenger vehicle (LT is light truck, ST is for special trailer, T is for temporary/spare use, and European spec tires have no letter). 225 is the section width of the tire in millimeters, and 60 is the aspect ratio (height/width— a lower number is shorter-wider). V is the speed rating and R means this is a radial tire. And finally, 16 is the wheel diameter in inches.
The 98V, listed after the above groups of digits indicates the load index (weight capacity) and speed rating of the tire. The number 98 indicates the tire can safely carry— when properly inflated— 1653 pounds. This scale ranges from a low of 60 (551#) to a high of 114 (2601#) for passenger tires. The speed rating ranges from the letter L (75 mph) to Z (149+ mph). In general, the higher the letter, the better the rating. For reasons I can’t fathom, the letterH(130 mph) is inserted betweenUand V of the scale. Also, W and Y speed ratings are actually higher, and more specific than Z, at 168 and 186 mph.
Tire age can be determined by locating the DOT (Department of Transportation) tire information number; (DOT followed by approximately 12 digits). The final four digits are the week and year the tire was manufactured (3114 would be the 31st week of 2014). This is listed only on one side of the tire, hopefully facing out! Maximum safe tire life is approximately 10 years, possibly sooner. Youmay also see the lettersMand S listed (M/S, M+S, MS), indicating the tire’s tread is optimized for all season (including snow) use.
Elsewhere on the tire are the UTQG (uniform tire quality grade) letters, indicating a tread wear, wet traction, and temperature rating. Expected tread life is assigned a number ranging between 100 and 500. Tires are tested by the manufacturer relative to a baseline of 100. A 400-rated tire could be expected to last twice as long as a 200 rated tire. It’s best to take this number with a grain of salt, as the computation process leaves plenty of wiggle room. Keep in mind also that many factors affect actual tire life, such as inflation pressure, wheel alignment, vehicle load, shock absorber condition, road conditions and driving habits. Straight-line wet-surface traction is also assigned a letter, with AA being the very highest, then A, B and C being the lowest. The tire’s resistance to heat is the final letter, with A again being the best and C the worst.
Confused? My head is spinning as well. A good starting point when shopping for tires is the tire information placard (sticker) on your vehicle’s door or door post, or the owner’s manual. The original tire specifications are listed for your vehicle and it’s important that a replacement tire equals or exceeds them. For a wonderfully informative source of tire information, go to www.tirerack.com, select Research and Advice, and Tech Center. I find and learn new things every time I go there!