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Safety and real-world fit
Calculations can compare numerical dimensions and stated costs, but cannot approve a tire or vehicle modification. Always follow the vehicle manufacturer's specification and use qualified advice when safety, fitment or legality is involved.
Quick reference
| Calculation | Formula | Example |
|---|---|---|
| Tire diameter (metric size) | rim × 25.4 + 2 × width × aspect ratio | 205/55 R16: 631.9 mm |
| L/100 km to US mpg | 235.215 / (L/100 km) | 6.5 L/100 km = 36.2 mpg (US) |
| L/100 km to UK mpg | 282.481 / (L/100 km) | 6.5 L/100 km = 43.5 mpg (UK) |
| Trip fuel cost | distance × L/100 km / 100 × price | 450 km × 6.5 / 100 × $1.80 = $52.65 |
| EV charging time (estimate) | energy needed / charger power | 40 kWh / 11 kW ≈ 3.6 h before losses |
US and UK miles per gallon differ because the gallons differ (3.785 L and 4.546 L), so always check which one a figure uses. Real charging takes longer than the simple estimate: some energy is lost as heat, and fast chargers slow down as the battery fills.