I developed a Realistic Inertial Load Ergometer (RILE), which simulates the inertial loads of sprint cycling and measures instantaneous power output. I used the RILE to test if:​ 1) cyclists select the gear ratio that maximizes power output during stationary starts 2) power output is greater from a stationary start while standing versus seated. 10 cyclists performed six seated and six standing seven-second sprints with different gear ratios on the RILE. I measured mean power, peak power, final velocity, work and time to peak were measured. In the seated potition 50% of riders selected a preferred gear that produced their greatest mean power. In the standing potition 60% of riders selected a preferred gear that produced their greatest mean power. Gear ratio had little effect on power, final velocity or work. Power, final velocity and work were all ~10% greater in the standing versus the seated position. These results in conjunction with aerodynamic data can be used to determine optimum durations for a cyclist to sit or stand to maximize sprint cycling performance.