Reifenumfangs

Reifenumfangs, translated as tire circumference, denotes the distance around a tire when it is mounted on a wheel and inflated to its nominal pressure. It is a geometric property determined by the tire’s overall diameter and is a key factor in vehicle dynamics and measurement systems.

Calculating Reifenumfangs uses the tire size designation. For example, a tire labeled 205/55R16 has width 205 mm, an aspect ratio of 55%, and a 16-inch wheel. The section height is width × aspect ratio, about 205 × 0.55 ≈ 112.8 mm. The overall diameter is roughly 2 × section height plus the wheel diameter (converted to millimeters): 2 × 112.8 mm + 406.4 mm ≈ 631.9 mm. The circumference is then C ≈ π × diameter ≈ 1.98 meters. More precise values can be obtained from manufacturer specifications or tire calculators.

Reifenumfangs varies with inflation pressure, load, and wear. Underinflation reduces the effective diameter and circumference; tread wear decreases the overall diameter over time. Temperature and manufacturing tolerances can also produce small differences. These changes, while sometimes subtle, can affect rolling resistance and handling characteristics.

Significance and applications. Accurate knowledge of Reifenumfangs is important for the accuracy of speedometers and odometers, gear ratios and acceleration behavior, cruise control performance, and fuel economy calculations. Changing tire sizes alters the circumference, which may require recalibration of electronic systems or adherence to vehicle manufacturer recommendations.

Measurement and references. Manufacturers often provide nominal circumference or rolling radius values in tire specifications. For detailed planning, tire-size calculators or measurements using a flexible tape can estimate Reifenumfangs from size codes and inflation settings.