Purpose Previous research has suggested that the optimal pacing strategy for self-paced exercise lasting > 4 min is a uniform distribution of work, but this posit is not well-established for prolonged endurance events. This study examined the utility of even-pacing during 20 km cycling time trials (TTs). Methods Fifteen well-trained male cyclists (V̇O2max = 4.80 ± 0.38 L•min-1) completed three best effort self-paced (SP) simulated 20 km TTs, followed by two even-paced trials. In one even-paced trial participants cycled to exhaustion (EPtlim) at a fixed intensity equivalent to their best SP performance. In the other EP trial participants were instructed to maintain this target intensity for a distance of 20 km, but the actual intensity was free to vary depending on the effort and cadence of the cyclist (EP-maintained). Cardiorespiratory, blood lactate and perceptual (RPE and affect) measures were assessed throughout. Results Nine out of fifteen cyclists failed the EPtlim task, completing 51-83% (10.3 to 15.3 km) of the work done in their SP trial. Failure as a result of even-pacing was associated with a faster rise in blood lactate, attainment of a higher relative intensity during SP and a moderate fast starting strategy. This failure was independent of the nature of the even-paced task. Conclusion By adopting an uneven, parabolic distribution of work, cyclists in this study were able to achieve an average intensity during self-paced exercise in excess of their maximum sustainable power output. A subsequent matched even-paced bout resulted in cumulative metabolic stress that could not be managed by moment-to-moment changes in power output. These results challenge the notion that strict even-pacing is optimal for endurance time trial events.