The pedal-based power meter has its advantages, so it has become a popular monitoring tool in cycling. This study aimed to examine the validity of the Favero Assioma Duo power pedal system (FAD) in comparison with the SRM, which is considered the gold standard under maximal-effort cycling conditions, and a widely used cycling test, the 20-minute Functional Threshold Test. Fourteen male adolescent cyclists completed a series of cycling intervals including 5, 15, 30, 60, 240, 600, and 1200 seconds (20-min Functional Threshold Test) with their maximal-effort performance on 2 separate days. Power output data were collected from the FAD and the SRM for analysis. Extremely strong correlations and excellent intraclass correlation coefficients (ICCs) were found between the power output values registered with the FAD and the SRM overall (r > .999, ICC = .996) and each power test (r > .98, ICC > .91). A low bias was found in power tests of longer durations (-3.2% at 240-s test, -3.3% at 600-s test, and -3.1% at 20-min Functional Threshold Test), while the bias augmented in shorter intervals (-2.7% at 5-s test, -3.6% at 15-s test, and -2.6% at 30-s test and -3.3% at 60-s test). A regression equation was proposed as y = -2.943 + 0.976x to diminish the bias (-0.2 W) with increased r value (>.98) and ICC (>.98). The FAD appears to be a valid tool for the measures of maximal-effort performance. The recorded power value reflects the true value with proposed regression equation.