Tire specs glossary
What every spec on a Tire Library detail page means.
Dimensional specs
| Spec |
Meaning |
| Width |
Section width — the tire's total width in millimeters |
| Aspect Ratio |
Sidewall height as % of width (65 means sidewall is 65% as tall as the tire is wide) |
| Rim Size |
Wheel diameter in inches |
| Diameter Overall |
Tire's total outer diameter (inches) |
| Section Width |
Same as Width — alternate name |
| Sidewall |
Description of sidewall appearance (e.g. Blackwall, White Letter) |
| Rim Approved Width |
Range of wheel widths this tire fits (e.g. 6.0-8.0) |
| Rim Diameter Metric |
Same as Rim Size, in metric |
Capacity & pressure
| Spec |
Meaning |
| Load Rating |
Load index — numeric code that maps to a max kg/lb per tire |
| Load Capacity Single |
Max load (lbs/kg) on a single tire |
| Load Capacity Dual |
Max load (lbs/kg) in a dual-wheel configuration |
| Max Inflation Pressure |
Maximum cold-inflation pressure (PSI/kPa) |
| Ply Rating |
Number of plies (4, 6, 8, etc.) — older measure of strength |
| Load Range |
Letter-based strength (SL, XL, E, F, ...) — newer equivalent of ply rating |
Speed rating (letter)
| Letter |
Max speed |
| L |
75 mph (120 km/h) |
| M |
81 mph (130 km/h) |
| N |
87 mph (140 km/h) |
| P |
93 mph (150 km/h) |
| Q |
99 mph (160 km/h) |
| R |
106 mph (170 km/h) |
| S |
112 mph (180 km/h) |
| T |
118 mph (190 km/h) |
| H |
130 mph (210 km/h) |
| V |
149 mph (240 km/h) |
| W |
168 mph (270 km/h) |
| Y |
186 mph (300 km/h) |
| (Y) |
above 186 mph — manufacturer-specific |
A three-part grade mandated by US DOT:
500 A A
│ │ └── Temperature grade: A > B > C
│ └──── Traction grade: AA > A > B > C
└──────── Treadwear grade: higher = longer expected tread life
| Flag |
Meaning |
| 3PMSF (Three-Peak Mountain Snowflake) |
Severe-snow certified |
| M+S (Mud and Snow) |
Meets basic mud/snow standards |
| Run-Flat |
Can be driven ~50 miles after a puncture |
| Studdable |
Can have studs installed for ice |
Other catalog fields
| Spec |
Meaning |
| Item Number |
Vendor SKU / part number — unique identifier from the supplier |
| UPC / EAN / ASIN |
Barcode identifiers |
| GM Code |
General Motors part code (where applicable) |
| Category |
High-level grouping: Passenger, Light Truck, Commercial, Trailer, Industrial, ... |
| Season |
Summer, Winter, All Season, All Weather |
| Terrain |
Highway, All Terrain, Mud Terrain, Rugged Terrain |
| Warranty |
Mileage warranty (e.g. 50000 = 50,000 miles) |
| Tread Depth |
New-tire tread depth (in 32nds of an inch) |
| Weight |
Tire weight in lbs/kg |
| Revolutions Per Mile |
Used by odometer/trip-computer calibrations |
| Rolling Circumference |
Distance covered in one full rotation |
