Telemetry - 7 min read
How to Read Telemetry
A plain-English guide to speed traces, throttle, brake, gear shifts, delta lines and driver-coloured track maps.
What telemetry shows
Racing telemetry is the car telling the story of a lap. The most useful traces for fans are speed, throttle, brake, gear and time delta. Speed shows how fast the car is travelling at each point on the circuit. Throttle shows how confidently the driver gets back to power. Brake shows where the driver slows the car and how aggressive the braking phase is. Gear helps identify traction zones, slow corners and long acceleration phases.
On Formula Visuals, telemetry is shown against distance around the lap. That matters because two drivers rarely arrive at the same corner at exactly the same clock time. Distance-based comparison lines the cars up by where they are on the circuit, which makes the braking point, minimum speed and exit speed easier to compare.
Reading the speed trace
The speed trace is usually the quickest way to spot where a lap is won or lost. A high point before a braking zone means strong straight-line speed. A sharp drop means heavy braking. The lowest point in the dip is the minimum corner speed. The climb after the dip shows how well the driver exits the corner.
If one driver brakes later but reaches a much lower minimum speed, they may not gain time overall. If another driver brakes a fraction earlier but keeps better minimum speed and returns to throttle earlier, the delta line often shows the real gain on corner exit and down the following straight.
Using throttle, brake and gears together
Throttle and brake traces explain why the speed trace changes. A clean lap normally has decisive braking, a stable coast or rotation phase, and a smooth return to full throttle. Hesitation on throttle after the apex often means the car was unstable or the driver had to protect rear tyres.
Gear changes add context. Short-shifting can show traction management. Holding a lower gear can show the driver wants more rotation or acceleration. If two drivers use different gears through the same corner, the faster lap may come from setup, driving style or available grip rather than simple bravery.
What the delta line means
The delta line is cumulative time gained or lost compared with a reference lap. If the line rises, the selected driver is losing time to the reference. If it falls, they are gaining time. A sudden change usually points to one braking zone, traction event or straight-line speed difference. A slow drift often points to tyre degradation, lift-and-coast, traffic or a setup difference that affects a whole sector.
The best way to use delta is to combine it with the track map. Find where the delta changes most, then look at the nearby speed, throttle and brake traces. That turns a vague statement like "lost time in sector two" into a more useful explanation.