Tire Load Index vs. Tire Speed Ratings
Comparing 2 standards across 13 specifications. 13 key differences identified.
The Tire Load Index (standardized under ISO 4000-1) is a numerical code assigned to a passenger or commercial tire indicating the maximum physical weight (in kilograms and pounds) the tire can carry when inflated to its maximum operating cold tire pressure. Spanning Load Index 70 (335 kg / 739 lb) to Load Index 120 (1400 kg / 3086 lb) per tire.
Tire Speed Ratings (standardized under ISO 4000-1 and ECE Regulation 30) are alphabetical index symbols indicating the maximum sustained velocity a tire can safely maintain under its rated load capacity. Ranging from Q (160 km/h / 99 mph) for dedicated winter tires to V (240 km/h), W (270 km/h), Y (300 km/h), and (Y) (>300 km/h / >186 mph) for hypercars.
Specification Comparison Table
13 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standardization
|
ISO 4000-1 / ETRTO / TRA Load Tables | ISO 4000-1 / UN ECE R30 / SAE J1561 |
|
Standard Load (SL) Pressure
|
Calibrated at 2.5 bar (36 psi) cold inflation pressure for passenger car tires | — |
|
Extra Load (XL / Reinforced)
|
Reinforced internal carcass calibrated at 2.9 bar (42 psi) for heavy electric vehicles (EVs) and SUVs | — |
|
Common Passenger Load Indices
|
LI 82: 475 kg (1,047 lb) | LI 88: 560 kg (1,235 lb) | LI 91: 615 kg (1,356 lb) | LI 95: 690 kg (1,521 lb) | — |
|
Heavy EV & SUV Load Indices
|
LI 100: 800 kg (1,764 lb) | LI 104: 900 kg (1,984 lb) | LI 108: 1,000 kg (2,205 lb) | LI 112: 1,120 kg (2,469 lb) | — |
|
Vehicle Axle Calculation
|
Sum of two tire load capacities on an axle must exceed the Gross Axle Weight Rating (GAWR) | — |
|
HL (High Load) EV Benchmark
|
New standard for heavy battery packs carrying higher load at equivalent tire volume and pressure | — |
|
Q Rating
|
— | 160 km/h (99 mph) — Studded and studless Nordic winter tires |
|
S & T Ratings
|
— | S: 180 km/h (112 mph) | T: 190 km/h (118 mph) — Standard family sedans, minivans, and all-season tires |
|
H Rating (High Speed)
|
— | 210 km/h (130 mph) — Touring sedans and premium crossovers |
|
V Rating
|
— | 240 km/h (149 mph) — Sport compacts and performance GT cars |
|
W & Y Ratings
|
— | W: 270 km/h (168 mph) | Y: 300 km/h (186 mph) — Exotic sports cars and track-focused performance vehicles |
|
(Y) In Parentheses
|
— | Speeds in excess of 300 km/h (>186 mph) — Certified individually with vehicle manufacturer for hypercars (Bugatti, Koenigsegg, Porsche GT3 RS) |