TYRE GRADING HUB
The complete guide to understanding tyre ratings and how they affect your safety, performance, and wallet.
WHY TYRE GRADES MATTER
Your tyres are the only contact between your vehicle and the road — just four palm-sized patches of rubber keeping you safe. Understanding tyre grades helps you make informed decisions about safety, performance, and value.
Click any section below to explore each rating system, see how it affects real-world performance, and learn what the numbers actually mean.
UNDERSTANDING THE EU TYRE LABEL
Since May 2021, all tyres sold in the EU (and applied in NZ by many brands) must display standardised ratings for fuel efficiency, wet grip, and external noise. The label also shows icons for snow and ice grip certification.
WET GRIP GRADE (A-E)
Measures braking distance on wet roads. The difference between Grade A and E is approximately 18 metres when braking from 80 km/h.
GRADE C IMPACT
FUEL EFFICIENCY GRADE (A-E)
Measures rolling resistance — how much energy is lost as the tyre rolls. Tyres account for 20-30% of a vehicle's fuel consumption.
GRADE C ANNUAL COST
EXTERNAL NOISE RATING
Measured in decibels (dB) — the sound level at the roadside. Classes A, B, and C indicate how the tyre compares to EU limits.
CLASS A
Quietest tyres — 3+ dB below limit
CLASS B
Average — meets limit
CLASS C
Loudest allowed
💡 3 dB = Double the Sound Energy
Every 3 dB increase represents a doubling of sound energy. A 71 dB tyre produces roughly twice the roadside noise of a 68 dB tyre.
SNOW & ICE GRIP ICONS
3PMSF (Three-Peak Mountain Snowflake)
Meets minimum snow grip performance standards per UNECE R117. Required for "severe snow conditions" certification.
Ice Grip Symbol
New since 2021. Indicates the tyre meets ISO 19447 ice grip standards — provides shorter braking on ice vs standard tyres.
UNIFORM TIRE QUALITY GRADING
Created by the US Department of Transportation in 1978, UTQG provides comparative ratings for treadwear, traction, and temperature resistance. Found on the sidewall of most passenger tyres.
⚠️ Important Limitation
UTQG ratings are assigned by manufacturers, not independently verified. They're useful for comparing tyres within a brand, but less reliable across different manufacturers.
TREADWEAR RATING (100-1000+)
A comparative rating based on wear during 11,520 km of testing. A tyre rated 400 should last twice as long as one rated 200 under the same conditions.
TREADWEAR 400
| Rating Range | Typical Use | Grip Level | Expected Life |
|---|---|---|---|
| 100-200 | Performance / Track | Maximum | 15,000-30,000 km |
| 200-400 | Sport / UHP | High | 30,000-50,000 km |
| 400-600 | Touring / All-Season | Good | 50,000-80,000 km |
| 600-800 | Economy / Comfort | Average | 80,000-120,000 km |
TRACTION RATING (AA, A, B, C)
Measures wet braking on asphalt and concrete at 64 km/h with locked wheels. Note: This doesn't test ABS performance, cornering, or hydroplaning resistance.
AA
15% of tyres — Premium performance
A
75% of tyres — Standard good grip
B
7% of tyres — Budget category
TEMPERATURE RATING (A, B, C)
Measures heat dissipation under load. Higher ratings allow safe sustained higher speeds. All tyres sold must achieve at least C.
| Grade | Max Sustained Speed | Test Requirement | Typical Use |
|---|---|---|---|
| A | > 185 km/h (115 mph) | 575+ km on test wheel | Performance, highway |
| B | 160-185 km/h (100-115 mph) | 500-575 km on test wheel | Standard touring |
| C | 137-160 km/h (85-100 mph) | Minimum standard | Budget, slow speed |
WHY TREAD DEPTH MATTERS
Tread grooves channel water away from the contact patch. As tread wears, water evacuation decreases exponentially — below 3mm, braking distances increase dramatically. NZ legal minimum is 1.5mm, but safety experts recommend replacing at 3mm (or 4mm for winter conditions).
📐 Different Tyres Start With Different Depths
A passenger car tyre at 6mm has 69% life remaining. The same 6mm on a mud-terrain tyre (16mm new) means only 28% life remaining. Select your tyre category first for accurate calculations.
STEP 1: SELECT YOUR TYRE CATEGORY
STEP 2: MEASURE YOUR TREAD DEPTH
TREAD ANALYSIS
SAFETY IMPACT
STATUS
NEW TREAD DEPTHS BY CATEGORY
| Category | New Depth | Replace At | Legal Min | Typical Examples |
|---|---|---|---|---|
| 🚗 Passenger Car | 7-9mm (typ. 8mm) | 3mm | 1.5mm | Corolla, Civic, Golf, Mazda3 |
| 🚙 SUV / Crossover | 9-11mm (typ. 10mm) | 3mm | 1.5mm | RAV4, CX-5, X-Trail, Outlander |
| 🛻 Ute / Light Truck | 10-14mm (typ. 12mm) | 4mm | 1.5mm | Hilux, Ranger, BT-50, Navara |
| ⛰️ 4WD All-Terrain (A/T) | 12-14mm (typ. 12mm) | 4mm | 1.5mm | Prado, Patrol, Pajero, Everest |
| 🪨 4WD Mud-Terrain (M/T) | 14-20mm (typ. 16mm) | 5mm | 1.5mm | BFG KM3, Maxxis Razr, Cooper STT |
| 🚚 Commercial / Truck | 12-20mm (typ. 15mm) | 4mm | 1.5mm | HiAce, Transit, NPR, Canter |
| 🏍️ Motorcycle | 5-7mm (typ. 6mm) | 2mm | 1.5mm | Sport, touring, cruiser tyres |
WET BRAKING TEST DATA (CONTINENTAL - 80 km/h → 0)
Tested on passenger car tyres (8mm new). Larger tyres show similar percentage increases.
| Tread Depth | % of New | Wet Braking | Increase | Status |
|---|---|---|---|---|
| 8mm (New) | 100% | 42.3m | — | ✓ Excellent |
| 6mm | 69% | 44.5m | +2.2m (+5%) | ✓ Good |
| 4mm | 38% | 48.2m | +5.9m (+14%) | Monitor |
| 3mm | 23% | 51.8m | +9.5m (+22%) | ⚠ Replace Soon |
| 2mm | 8% | 56.4m | +14.1m (+33%) | Replace Now |
| 1.6mm (UK Legal) | 2% | 60.9m | +18.6m (+44%) | ✗ Critical |
| 1.5mm (NZ Legal) | 0% | 62.0m | +19.7m (+47%) | ✗ Minimum |
🏔️ A/T and M/T Tyres Have Different Wet Characteristics
All-Terrain (A/T): ~5% reduced wet grip vs highway tyres due to open tread pattern. Excellent in gravel, mud, light off-road.
Mud-Terrain (M/T): ~15% reduced wet grip on sealed roads. Large voids channel mud but take longer to clear water. Best for serious off-road use.
RUBBER AGES EVEN WHEN NOT USED
Tyres degrade over time through oxidation — the rubber hardens, cracks form internally, and grip deteriorates. Most manufacturers recommend replacing tyres after 6 years, regardless of tread depth. Maximum service life is 10 years.
DOT CODE DECODER
Find the DOT code on your tyre sidewall. Enter the last 4 digits:
AGE DEGRADATION CURVE
Grip loss accelerates with age. Based on MDPI research showing r = -0.777 correlation between age and performance.
4 YEAR OLD TYRE
| Age | Grip Retention | Degradation Rate | Recommendation |
|---|---|---|---|
| 0-2 years | 98-100% | 1%/year | ✓ Optimal |
| 2-4 years | 93-98% | 2.5%/year | ✓ Good |
| 4-6 years | 85-93% | 4%/year | ⚠ Inspect annually |
| 6-8 years | 73-85% | 6%/year | Replace soon |
| 8-10 years | 59-73% | 7%/year | Replace now |
| >10 years | <59% | Rapid | ✗ Do not use |
🌡️ Hot Climate Warning
If you live in a hot climate (regular 30°C+ temperatures), tyres age approximately 35% faster. Consider replacing at 4-5 years instead of 6.
PRESSURE AFFECTS EVERYTHING
Incorrect tyre pressure affects braking distance, fuel consumption, tyre wear, and handling. According to Michelin, a 1 bar (14 PSI) difference can add 11 metres to wet braking distance. Different vehicles and load ranges require different pressures.
📋 Always Check Your Door Placard First
The recommended pressure for YOUR specific vehicle is printed on a sticker inside the driver's door jamb or in your owner's manual. The values below are general guidelines by vehicle category.
STEP 1: SELECT VEHICLE TYPE
RECOMMENDED PSI BY VEHICLE TYPE
| Vehicle Type | Typical Weight | Light Load | Normal | Heavy Load | Load Range |
|---|---|---|---|---|---|
| 🚗 Hatchback | 1,100-1,400 kg | 28-30 | 30-33 | 33-36 | SL |
| 🚙 Sedan | 1,300-1,600 kg | 30-32 | 32-35 | 35-38 | SL |
| 🚐 SUV / Crossover | 1,500-2,000 kg | 32-35 | 35-38 | 38-42 | SL/XL |
| 🛻 Ute (Empty) | 1,800-2,500 kg | 32-36 | 36-40 | 40-50 | C/D |
| ⛰️ 4WD / Off-Road | 2,000-3,000 kg | 32-38 | 38-44 | 44-55 | C/D/E |
| 🚐 Van / People Mover | 1,800-2,600 kg | 36-40 | 40-45 | 45-55 | C |
| 🏎️ Sports Car | 1,300-1,800 kg | 32-35 | 35-38 | 38-42 | SL/XL |
| 🚚 Commercial / Light Truck | 2,000-3,500 kg | 45-50 | 50-58 | 58-70 | D/E |
LOAD RANGES EXPLAINED
Load range determines the maximum pressure and load capacity of a tyre. Higher load ranges support more weight but require higher inflation.
| Load Range | Max PSI | Typical Use | Sidewall Marking |
|---|---|---|---|
| SL (Standard Load) | 36 PSI | Passenger cars, light SUVs | No marking or "SL" |
| XL (Extra Load) | 42 PSI | Heavy sedans, loaded SUVs | "XL" or "Extra Load" |
| C | 50 PSI | Light trucks, vans, utes | "LT" or "C" (6-ply rating) |
| D | 65 PSI | Heavy utes, 4WDs, commercial | "LT" with "D" (8-ply rating) |
| E | 80 PSI | Heavy commercial, trucks | "LT" with "E" (10-ply rating) |
PRESSURE DEVIATION IMPACT
See what happens when your pressure is above or below the recommended level.
PRESSURE IMPACT
⬇️ UNDERINFLATED
- +10-20% braking distance
- +5% fuel consumption
- Edge wear (outer shoulders)
- Overheating → blowout risk
- -25% tyre life per 5 PSI low
- Sluggish handling
- 40% of accidents involve underinflation
✓ CORRECT PRESSURE
- Optimal braking distance
- Best fuel economy
- Even tread wear
- Maximum tyre life
- Safe handling response
- Proper load distribution
- Comfortable ride quality
⬆️ OVERINFLATED
- Reduced contact patch
- Centre tread wear
- Harsh ride quality
- Less grip in wet
- Increased puncture risk
- Poor shock absorption
- Longer braking on bumps
🌡️ Temperature Affects Pressure
Tyre pressure changes approximately 1 PSI for every 5°C temperature change. In NZ's variable climate:
- Check pressure when tyres are cold (not driven for 3+ hours)
- Warm tyres can read 4-6 PSI higher than cold
- Check monthly and before long trips
- Seasonal swings of 10-15°C mean pressure changes of 2-3 PSI
🚐 Loading Your Vehicle?
When carrying heavy loads or towing, increase rear tyre pressure by 4-8 PSI (check door placard for "loaded" pressure). Front/rear distribution changes significantly:
- Empty ute: ~60% front / 40% rear
- Loaded ute: ~45% front / 55% rear
- Towing: Add ~10% of trailer weight to rear axle (tongue weight)
WHAT SPEED RATING MEANS
The speed rating indicates the maximum speed a tyre can safely sustain under load. It also reflects the tyre's heat resistance and often correlates with handling performance. Found as the last letter in your tyre size code (e.g., 205/55R16 91V).
⚠️ NZ Context
With a 100 km/h speed limit on most NZ roads, ratings above T (190 km/h) are primarily about construction quality and handling characteristics rather than actual speed capability.
SPEED RATING CHART
Click any rating to see details:
SELECT A SPEED RATING ABOVE
Click any letter to see its maximum speed and typical applications.
| Rating | Max Speed | Typical Use | Common Vehicles |
|---|---|---|---|
| N | 140 km/h | Temporary spare | Space saver tyres |
| Q | 160 km/h | Winter tyres | Studded/severe snow |
| S | 180 km/h | Family sedans | Corolla, Civic, Mazda3 |
| T | 190 km/h | Family/Light truck | SUVs, Utes, Vans |
| H | 210 km/h | Sport sedans | European sedans, coupes |
| V | 240 km/h | Sports cars | Hot hatches, sports sedans |
| W | 270 km/h | High performance | Performance cars, AMG, M |
| Y | 300 km/h | Supercars | Porsche, Ferrari, Lamborghini |
| (Y) | >300 km/h | Hypercars | Bugatti, Koenigsegg |
💡 Never Downgrade Speed Rating
Always replace with tyres that meet or exceed your vehicle manufacturer's specified speed rating. You may upgrade (H→V) but never downgrade — it affects handling characteristics even at normal speeds.
TEST THESE FACTORS IN ACTION
See exactly how EU grades, tread depth, tyre age, and pressure affect your stopping distance with our physics-based braking simulator.
🚗 Launch Braking Simulator →
