Race Simulator

How the Race Simulator Works

Upload a FIT file recorded on the course (or any file with distance and altitude data). The tool splits the route into gradient-homogeneous segments based on the minimum segment length and gradient tolerance you configure. Short consecutive segments with similar gradients are merged to avoid noise from GPS elevation sampling.

Each segment is classified into a terrain band - steep downhill, slight downhill, flat, slight uphill, or steep uphill - and a power factor is applied: you push harder on climbs and back off on descents. The base power is then calibrated via a binary search so that your W' (anaerobic capacity) is fully spent by the finish, squeezing out the fastest possible total time without going negative on W' mid-course.

W' balance uses the Skiba W'bal model: riding above FTP drains W' at (Power - FTP) x time, while riding below FTP recovers W' exponentially based on how far below FTP you ride. The tool uses the CP/W' power-duration model (P = W'/t + CP) to estimate sustainable power for the course duration. If the course ends on a long downhill or has many recovery sections, it may be impossible to fully exhaust W' - the strategy still maximises pace on climbs, and the results show how much W' was left. For the most accurate results, keep your FTP and W' up to date in your Rider Profile.