Tyre pressure directly affects safety, fuel efficiency, and wear patterns.
Contact Patch Engineering
The contact patch is the area of tyre in contact with the road. For a 1500 kg vehicle:
Approximate load per tyre:
1500 ÷ 4 = 375 kg
Contact patch size is determined by:
Load ÷ Inflation Pressure
Under-inflation causes:
- Increased sidewall flex
- Heat buildup from internal friction
- Edge wear
- Risk of blowout
Over-inflation causes:
- Crown wear
- Reduced braking efficiency
- Smaller contact patch
- Poor wet grip
Rolling Resistance & Fuel Economy
Rolling resistance coefficient (RRC) depends on:
- Compound elasticity
- Inflation pressure
- Tread depth
- Vehicle load
Under-inflation by just 6 PSI can increase fuel consumption by 3–5%.
Mobile technicians use calibrated digital gauges and torque sticks to ensure:
- Correct PSI
- Proper wheel nut torque (typically 110–140 Nm depending on vehicle)