Time delta¶
The time delta is how a run compares to the reference run, expressed as a difference in seconds. Racecraft surfaces it at two levels of detail: at split points, and continuously through the run.
The split-level delta¶
For each split, the run shows:
- its own time at that split
- the reference run's time at the same split
- the delta — the run's time minus the reference's time
Conventions:
- a negative delta means the run reached this split faster than the reference — ahead by that amount
- a positive delta means the run reached this split slower — behind by that amount
The split-level delta is cumulative: it's the gap at that split, not the gap added by the section leading up to it. To see how a single section played out, look at how the delta changed between two consecutive splits.
Example: a run with -0.2s at split 1 and +0.4s at split 2 was
0.2s ahead entering the section, and is 0.4s behind at the next
split — meaning the section itself cost the rider 0.6s.
The continuous time delta¶
The continuous delta is plotted across the run as a curve. At every moment, it shows how far ahead or behind the reference the run currently is.
Reading it:
- a dip in the curve — the run is gaining time on the reference in that region
- a rise in the curve — the run is losing time
- the value at the end — the total finish-line delta
The continuous delta is the layer that tells you where exactly time was won or lost. Two runs can have identical split times and very different continuous deltas — one rider losing time on a corner entry and gaining it back on the exit, while another does the opposite. The split times don't distinguish them; the continuous delta does.
Uncertainty regions¶
Alignment between a target run and the reference isn't perfect everywhere. In sections where the camera saw something ambiguous — a long uniform stretch, a fogged or knocked camera — the alignment is less confident, and the continuous delta is less precise.
The product surfaces these as uncertainty regions along the curve. They don't mean the delta is wrong; they mean it's measured with a wider tolerance there. Treat them as ranges rather than points.
What the delta won't tell you¶
- why the time changed hands. It identifies where; figuring out why — line, body position, braking, gearing — is the rider or coach's job.
- anything if the runs aren't on the same track. The whole delta machinery assumes a shared reference. If the reference no longer reflects the track, the delta is misleading.
The delta is a high-resolution lens on a comparison; it's not a verdict on it.