Race Simulator
Upload a FIT or GPX file to split the course into gradient segments and estimate your best time using your power profile. The model assumes no drafting.
Pacing Mode
Power Profile
Rider and Bike
Upload a file to get started
Fill in your rider details, then hit Simulate Race.
Estimated finish time
Avg speed and power per segment
W' (anaerobic capacity) usage
Elevation profile with terrain coloring
How the Race Simulator Works
From course file to pacing segments
Upload a FIT or GPX file containing distance and altitude data. The simulator divides the course into sections with similar gradients. Minimum segment length controls how detailed the course becomes, while gradient tolerance controls how much the slope must change before a new segment is created. Very short segments are merged with a nearby segment to reduce noise in the elevation data.
How time is estimated
For each segment, the simulator estimates speed and time from its target power. The calculation considers gradient, rider and bike weight, aerodynamic drag, rolling resistance, drivetrain efficiency, altitude, temperature and wind. Results include estimated finish time, average speed, average power, total work and detailed values for every segment.
Pacing modes
Manual: Creates a Balanced starting plan from your Critical Power, adding power on climbs and progressively reducing it on descents. You can then adjust a terrain group, a selected part of the course or an individual segment. Your chosen powers are preserved and the results are recalculated.
My best effort: Searches for the fastest pacing plan that remains within your Critical Power and W' limits. Power is moved toward segments where it is expected to save the most time.
Target power: Searches for the fastest distribution that stays within your selected average-power target. The simulator uses your W' and estimated course duration to infer a compatible Critical Power for the calculation.
Target finish time: Searches for the lowest-work pacing plan that reaches the selected finish time. This mode does not apply Critical Power or W' limits. If the requested time cannot be reached within the configured maximum power, the fastest available plan is shown with a warning.
CP, W' and sustainability
Critical Power, or CP, represents the power you can sustain aerobically for a long effort. W' represents the limited amount of additional work you can perform above CP. In modes that use these values, W' is spent above CP and can recover below CP. If W' falls below zero, or the modeled average-power limit is exceeded, the plan is marked as unsustainable.
On sufficiently steep descents, the simulator allows coasting. On gentler descents, optimized plans progressively limit power because additional pedalling may produce little time benefit. The configured maximum power limits the target for any single segment.
What the estimate does not include
The result is an estimate, not a guaranteed race time. The model assumes steady conditions and no drafting. It does not account for braking, corners, traffic, changing road surfaces or short accelerations within a segment.