Wheel & Tire
Four postcard-sized patches do everything
Every force a car experiences — accelerating, braking, cornering — passes through four tire contact patches, each about the size of a postcard. The tire is a precision composite of rubber, fabric plies and steel belts; the wheel is the rigid interface bolting it to the hub.
What it does
Grips the road, carries the car’s weight on contained air, and absorbs the first layer of road harshness.
At all four corners — the only parts of the car that touch the road.
How it works
- The air inside, not the rubber, carries the car: inflation pressure tensions the casing like a drum skin.
- Body plies of polyester cord give the tire its shape and flexible strength.
- Two steel belts under the tread stabilize the contact patch so it stays flat and square on the road.
- The bead — a hoop of steel wires — clamps the tire onto the rim flange, sealed by air pressure alone.
- Tread grooves evacuate water; the rubber compound itself interlocks with road texture at a microscopic level to create grip.
Key numbers
| Contact patch | ≈ 100 – 150 cm² per tire |
| Pressure | 2.2 – 2.7 bar typical |
| Construction | Radial: plies + 2 steel belts |
| Tread depth | 8 mm new, 1.6 mm legal limit |
| Life | 40,000 – 80,000 km |
Warning signs of trouble
- Vibration at speed — imbalance or a bent rim.
- Wear on one shoulder — alignment off.
- Wear in the center or both edges — over/under-inflation.
- Sidewall bulge — broken cords inside. Replace immediately.
Maintenance & care
- Check pressures monthly, cold — tires lose ~0.1 bar/month naturally.
- Rotate front↔rear every ~10,000 km for even wear.
- Replace at 3 mm for wet safety, regardless of the 1.6 mm legal limit.
- Tires age out: replace at ~8–10 years even with good tread.
Frequently asked questions
What does the wheel & tire do?
Grips the road, carries the car’s weight on contained air, and absorbs the first layer of road harshness.
How does a wheel & tire work?
Every force a car experiences — accelerating, braking, cornering — passes through four tire contact patches, each about the size of a postcard. The tire is a precision composite of rubber, fabric plies and steel belts; the wheel is the rigid interface bolting it to the hub.
What are the signs of a failing wheel & tire?
Vibration at speed — imbalance or a bent rim. Wear on one shoulder — alignment off. Wear in the center or both edges — over/under-inflation. Sidewall bulge — broken cords inside. Replace immediately.
How do you maintain a wheel & tire?
Check pressures monthly, cold — tires lose ~0.1 bar/month naturally. Rotate front↔rear every ~10,000 km for even wear. Replace at 3 mm for wet safety, regardless of the 1.6 mm legal limit. Tires age out: replace at ~8–10 years even with good tread.