Before anybody can go fast in a kart or in a race car they must first learn the very basics of racing. One of the very basic skills needed to improve your time around a track is to be able to read a turn and recognize where the apexes of that turn are located. The first thing to learn is the definition of an apex.
The apex of a turn is the geometric center of that turn. Every corner has three different apexes: an early apex, geometric apex, and late apex. Each apex will give you a different result when used. Here is an example of these three apexes:
So this diagram shows the 3 apexes and what each one results in. Obviously an early apex is going to leave you with the least amount of exit speed and the late apex will give you the greatest amount of exit speed which is critical in a go-kart. The Stratus karts used at Andretti Indoor Karting have 9 horsepower engines in them and almost no torque. With that little horsepower, you have to use all the momentum you can on the exit of the turn to produce the best lap.
To hit the correct late apex, you must get all of your braking done before you decide to turn in. If you come into the turn too hot you will slide past the apex and ruin the turn. You do not want to be braking in the middle of the apex because this is killing your momentum exiting the corner. Getting back to the throttle as quick as you can is the only way to maximize your exit speed.
The rule of thumb to think about is this: Slow In Fast Out. You come into the turn slow but you exit at a greater rate of speed. Most people I see come in and think that they will just slide the kart around not using the brakes and be able to put down a good lap time. They come into the corners way too fast and slide out to the outside of the track, most of the time almost coming to a complete stop. They are examples of the wrong way to drive: Fast In Slow Out.
Study this diagram and try to apply it to your every day driving around town and then come to Andretti’s and apply it on the race track! Just remember that smooth is fast and to enter a turn slow so you can maximize your exit speed. Here is a link to a video from Andretti’s that will give you a real life example of apexing: http://www.youtube.com/watch?v=OVmSxWE5Ctk
-Pat Wilmot
A Karter's Perspektive 