Constant-Deflection Model for Road and Gravel Bicycle Tire Pressure: Empirical Calibration, Uncertainty Propagation, and Cross-Validation

Technical white paper of the BikeLab PSI Calculator. Presents the physical-statistical model built on Frank Berto's constant-deflection criterion (15% tire drop), with four original contributions: real-width correction re-anchored over 321 BicycleRollingResistance measurements; front coupling P_f = 0.93·P_r calibrated against SILCA and Rene Herse; uncertainty propagation via Latin Hypercube Sampling (N = 10,000); and global sensitivity analysis via Sobol indices (81,920 evaluations per case). Cross-validation over six configurations: 9/12 wheels within ±10% of the reference average. Tool: bikelabstudio.com/articles/psi-calculator-en.html — Versión en español: bikelabstudio.com/articles/psi-calculator-es.html