#1 – Getting to the throttle too early and/or too hard in a corner
This problem usually stems from another problem, over-slowing for a corner. I see it all day every day with first timers who don’t know how fast they can take a certain turn, they’ll get to the braking zone, slam on the brakes and then get to their turn in point and realize they could have gone faster so they mash on the throttle again and the car magically understeers and they miss their apex by five feet.
What they aren’t recognizing is what the car is doing when they get on the throttle too early. Even if you’re the smoothest driver on track if you get to the throttle too early then you’re transferring weight off of the front tires and onto the rears. The result is more traction at the rear and less up front where you need it to help the car turn down to the apex. It’s kinda like trying to turn a bicycle while popping a wheelie. This is even worse in a FWD or AWD car since you’re also adding power to the front wheels at the same time making it even more likely that the front tires will break traction. So before you start shopping for stickier and wider front tires, try keeping more of that contact patch on the ground by not getting on the throttle until you start unwinding the steering wheel and tracking out to your exit even if you do over-slow for the corner. Next lap brake a little later or a little less and carry more speed until you get it right!
The second part of this is getting on the throttle too hard when you still have your steering wheel turned. This can result in “throttle oversteer” which might look cool, but it certainly isn’t the fastest or the easiest on your equipment. The general rule of thumb is to add throttle smoothly as you unwind your steering wheel. If you unwind the wheel 10% then only add 10% throttle, unwind 20% add 20% throttle, and so on until your full throttle in a straight line.
#2 – It’s all about how you release
With so much attention paid to how you apply the brakes and the throttle on track it amazes me why nobody concentrates on how they’re releasing the brakes and the throttle. This is arguably more important, especially when talking about the brakes. So you’re screaming down the front straight at Buttonwillow, you get to your braking point and you jump on the brakes nice and smooth threshold braking in a straight line like you’re Lewis Hamilton, you get to your turn-in point and you pop your foot off the brakes like something bit your toe, turn the wheel and…understeer off into the weeds. You weren’t on the throttle too early that time, why did it still understeer? It’s because you leapt off the brake pedal like it was your high school girlfriend when you heard the garage door opening. Under hard braking you’re really digging that front end into the ground compressing your front springs. When you pop off the brakes too quickly that spring shoots the front end of the car back up and transfers weight back towards the rear. Instead, smoothly release the brake pedal as you turn into the corner, controlling those front springs and keeping that weight up front.
This is what's known as trail braking and it’s the opposite of what I just explained about adding throttle as you unwind the wheel. Again the general rule of thumb is to let off the brakes as you turn the wheel down to your apex. Turn the wheel 10%; release the brakes 10% and so on. Be careful though, too much brake pressure can either overload keep too much weight on your front tires and overload them as you’re trying to turn again resulting in understeer or it can result in too little weight on the rear tires resulting in oversteer as you turn in. It’s a balance that will come with seat time and practice. Think about these principles of weight transfer and controlling those springs when you come off the throttle as well. If you have to make a speed adjustment mid corner or on exit because you’re going too fast don’t pop off the throttle too quickly as it could snap oversteer on you. I see this with the throttle the most over elevation changes when the car gets light and people’s first reaction is to pop off the throttle.