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205/55R 16 89V
205
The first number in this series refers to the tire's section width, or distance from sidewall edge to sidewall edge (in millimeters) when measured up and over the tire's tread. Generally speaking, the larger this number is, the taller and/or wider the tire will be.
55
This number is the tire's aspect ratio, or its section height compared to its section width. In this case, the section (or sidewall) height is 55 percent of the section width. This number can be very indicative of a tire's purpose. Lower numbers, like 55 or less, mean a short sidewall for improved steering response and better overall handling.
R
The "R" refers to radial construction, which has been the industry standard in passenger car tires for more than twenty years. Prior to radial tires, most cars came with bias-ply tires which had a crude construction that made for poor handling. Bias-ply tires are still used for certain truck applications.
16
This is the rim diameter, in inches, for which the tire was sized. Pay particular attention to this number if you plan on upgrading your wheel size. If your wheel diameter changes, you'll have to purchase a new set of tires that match this new diameter.
89
A tire's load index is a measurement of how much weight each tire is designed to support. To find out what "89" means, it must be looked up on the official Maximum Load-Carrying Capacity Per Tire chart. In this case, 89 indicates a maximum weight of 1,260 pounds. Remember that this is per tire, which means you have to multiply by four to get the total capacity for a complete set of tires.
V
The speed rating is a measurement of what speed the tire is designed to run at for extended periods. A "V" speed rating signifies that this tire can be run safely at speeds of up to 149 mph for extended periods. Will it explode if it goes to 155? No, not immediately. But it might if it is run at that speed for several minutes.
Here is a complete list of the various tire speed ratings, and their associated letters:
S 112 mph
T 118 mph
U 124 mph
H 130 mph
V 149 mph
*W 168 mph
*Y 186 mph
* For tires having a maximum speed capability of more than 149 mph, a ZR may appear in the size designation. For tires having a maximum speed capability greater than 186 mph, a ZR must appear in the size designation.
