Measuring real tire dimensions
Cover Tire Internal Air Volume by Size: Estimation and Calculation
Learn how to estimate the internal air volume of a tire from its sidewall markings, including width, aspect ratio, and rim diameter. Use simple torus approximation and practical examples to understand how many gallons or liters of air fit inside common tire sizes.
Bicycle Tire Air Volume: Estimation and Calculator
Estimate bicycle tire air volume in liters from the ETRTO size on the sidewall. Includes the torus formula, worked examples, a size table and the limits of the estimate.
Actual Tire Dimensions by Size: Nominal Sizes vs Manufacturer Specifications
How to read tire sidewall sizes, calculate sidewall height and diameter, and see why the same size tires have different actual widths in manufacturer dimension charts.
Tire Cross-Sectional Profile: Understanding Its Shape and Dimensions
How to read tire sidewall size numbers, calculate sidewall height, diameter and circumference, and why calculated geometry differs from real fitment.
Tire Contact Patch Size Calculator: Estimating Area from Load and Pressure
Estimate tire contact patch area by dividing load per tire by inflation pressure. Learn which sidewall numbers matter, how to convert units, and where the estimate falls short.
Tire Runout Tolerance: Understanding and Measuring Out-of-Round Tires
How to read tire sidewall sizes, what radial and lateral runout tolerance means, and how to measure, recognize and correct an out-of-round tire.
Tire Crown Radius: Meaning, Measurement and Calculation
What tire crown radius means, why it is not printed on the sidewall, and how to measure it with a straightedge and calculate it with the chord and sagitta formula.
Tractor Tire Lug Angle: Meaning and Measurement
What tractor tire lug angle means, how to measure it, and how to read sidewall markings such as 480/80R46, R-1W, load index and speed symbol, with worked size calculations.
How Tire Width Affects Contact Patch Shape
How tire width changes contact patch shape, starting with sidewall markings like 225/45R17 94W. Covers patch area, length and width, sidewall height, diameter, and fitment limits.
How Much Air Pressure Should a Bicycle Tire Have?
How to read the PSI, bar and size markings on a bicycle tire sidewall, choose a pressure for your width and load, and understand tire volume and geometry.