The racing line is the path that lets you carry the most speed through a corner and onto the next straight. For a single corner it usually runs outside-inside-outside: turn in from the outside edge, clip the inside at the apex, and let the car run back out to the edge on exit. Where you put the apex depends on what comes next: a late apex before a long straight, a more geometric line in fast corners, and sometimes an early apex when a slower corner follows.
Why the widest arc is faster
A tire can only produce so much grip, and the speed you can carry through a turn depends on the radius of your path. Using the full width of the track opens the radius, which raises the speed possible for the same grip (Virtual Racing School).
The three reference points
- Turn-in point: where you start steering.
- Apex (clipping point): where your inside tires pass closest to the inside edge. It can be in the geometric middle of the corner, earlier, or later (Speed Secrets).
- Track-out point: where the car returns to the outside edge on exit.
Geometric, late and early apex
| Line | What you do | When to use it |
|---|---|---|
| Geometric | Constant radius, apex at the middle of the corner | Fast corners: Ross Bentley's rule of thumb is that the faster the corner, the closer to the geometric line you should drive (quoted on Wikipedia) |
| Late apex | Turn in later from a wider position, apex past the middle, straighter exit | Corners that open onto a straight, so you can accelerate earlier (VRS) |
| Early apex | Turn in sooner for a faster entry, compromised exit | When a slower corner follows closely and exit speed matters little (VRS) |
The reasoning behind the late apex is simple: speed carried out of a corner is carried all the way down the straight, so it is worth more than speed on the way in. VRS gives the last corner at Road America as a late-apex example: stay wide on the brakes, turn in late, reach minimum speed before the apex, and be accelerating hard by the time you clip it (VRS).
How to tell if your apex is wrong
Ross Bentley's rule of thumb: if you run out of track on exit, your apex was probably too early, so turn in a little later next lap; if you have room to spare on exit, your apex was probably too late (Speed Secrets). Throttle timing can cause the same symptoms, so change one thing at a time.
Braking and the line work together
The line only works if your speed is right at turn-in. The Skip Barber Racing School teaches carrying some brake past the turn-in point and releasing it progressively (trail-braking), and placing the throttle application point as early as the car can accelerate without running wide. Lower-powered cars can usually get on the throttle earlier in the same corner (Going Faster! excerpt, Bentley Publishers).
Corner sequences and exceptions
- Linked corners: treat them as one sequence. The ideal exit of one corner may not reach the edge if that sets up a wider entry to the next (VRS).
- Chicanes: look for the straightest path through both parts.
- Bumps, camber and curbs: the textbook line assumes even grip. VRS points to F1 cars at Monaco moving off-line after Casino to avoid a bump that would upset the car.
Why this matters on a simulator
Laser-scanned tracks reproduce bumps, camber and surface changes, so the line that works in a simulator is shaped by the same features as the real circuit (iRacing). Simulators also let you repeat one corner many times and compare laps, which makes them a good place to practice line choice. For more, read how to improve your lap times and how to read telemetry. Background reading: racing line.
Put it into practice
SimsForHire brings full-motion racing simulators to corporate events, private parties and brand activations around Miami. A live leaderboard is a quick way to see who has worked out the line. Full-motion rigs are $2,750 per rig per day, plus tax and insurance. See pricing or call (754) 228-5654.