Trimming Distance and the Challenge of Late Apexing

The traditional late apex. Photo credit: oldbastardsracing.com
Trimming Distance and the Challenge of Late Apexing
The traditional late apex. Photo credit: oldbastardsracing.com

When accelerating out of an isolated corner onto a reasonably long straight, the tendency among beginner and intermediate drivers is to compromise entry speed slightly so they can take a later apex. They square off the entry, the apex later – usually ⅔ – ¾ around the corner to roll on the throttle slightly earlier and capitalize on that added exit speed down the straight. The theory is that a later apex allows a longer application of the throttle, which produces a minuscule increase in exit speed and a longer, more assured throttle application without a lift or wheelspin – but the real advantage is the magnification of that extra mile an hour down the length of the straight.

Nearly every coach, probably more interested in getting home to their family rather than squeezing every ounce of performance from their student, will instruct the student on the merits of a late apex, and mention something along the lines of, “The longer the straight, the more important the exit speed.” I can’t argue with any of that, but in following that simplified instruction, people run the risk of falling into bad habits. The question is, in compromising this entry phase by turning in later and straightening the exit phase of the corner, how much entry-phase compromise is too much?

Keeping in mind that the basic aim of any corner, when searching for speed and not positioning, is to exit the corner cleanly and as early as possible while rolling the shortest possible distance throughout the corner. By juggling these aims, we can determine where our ideal apex is: The point at which we’re able to accelerate cleanly off the corner is our apex. It’s where we can unwind the steering and apply the throttle assertively, without a lift, without much oversteer and, of course, without running off the track.

Trimming Distance and the Challenge of Late Apexing
In actuality, the approach to a geometric apex isn’t that much different from that of a late apex. Photo credit: formula1-dictionary.net

However, turning in later to try and straighten the car for a tidy exit, the driver lengthens the route through the corner and takes longer to meet their minimum speed. So, it’s important to remember the aim when rolling into apex is to minimize time spent from rolling off the brakes into the apex, even if the apex is considerably later in the corner. This is the aim with every corner-entry phase, but when we’re thinking about later apexes it’s important not to get coaxed into a false sense of security and allow ourselves to linger or over-slow because a later apex supposedly calls for that – it’s not actually the case.

How can you determine the ideal rolling speed? The experienced usually have an accurate speed sensor located somewhere in their posterior, but for those getting the hang of it all, it can be mystifying. It’s something that telemetry has made easier in recent years, but it can always be done by altering the line methodically while working within several reference points.

If the exit speed can be retained, and the apex remains the same point at which the driver begins to truly accelerate – not just the point at which they apply maintenance throttle – the driver can try to “trim the fat” by turning in earlier. The driver ought to focus first on the exit speed, then the entry speed and, lastly, the mid-corner speed. By following this order, the line can be trimmed to find that perfect compromise between minimal distance covered and the right line for a clean exit.

With this system, we can go by several points to assess whether we’re truly at the limit.

  • Make sure the apex is the point at which acceleration begins.
  • If the car is unable to accelerate cleanly at the apex, it’s too early.
  • If the car can accelerate before the apex, it’s under the limit or the line is based on an apex that’s later than necessary.

Again, this isn’t to negate the truths that a late apex yields some considerable gains in particular corners and that the exit ought to be the focus, but to remind the eager student that the right entry speed is very important as well. Unless the car has incredible amounts of power, or the straight in focus is unusually long, the speed into the corner still determines the exit speed to some degree, and never should a driver give themselves the chance to nap in the middle of the corner, especially if they’re following a tired old adage.

About Tommy Parry 112 Articles
Tommy Parry has been racing and writing about racing cars for the past seven years. As an automotive enthusiast from a young age, Tommy worked jobs revolving around cars throughout high school and tried his hand on the race track on his twentieth birthday. After winning his first outdoor kart race, he began working as an apprentice mechanic to amateur racers in the Bay Area to sharpen his mechanical understanding. He has worked as a trackday instructor and automotive writer since 2012 and continues to race karts, formula cars, sedans and rally cars in the San Francisco region.
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