Q: Could you please tell me what a momentum car is?

ask-ross-bentley-q&aQ: Could you please tell me what a momentum car is? I know from your tips that a car has to be driven on the rugged edge of it. How does it relate to the term? And, if I am racing how cautious I need to be thinking about crashes? Forgive me if it sounds weird but please let me know.

A: People in the sport talk about momentum cars when they refer to one that has less engine power than cornering grip. For example, a Spec Miata or a low-horsepower open-wheel car. To be fast in these cars you need to minimize the amount you slow them down, since they don’t accelerate back up to speed very quickly. But they have good cornering grip, so you don’t need to slow them very much for the corners, meaning you’re able to carry momentum through the turns.

The opposite would be a car with lots of engine power and less cornering grip. In this type of car, you would need to slow more for the corners, and then rely on the power to re-accelerate it on the straights. That’s the opposite of a momentum car.

How cautious should you be about thinking about crashing? That’s impossible for me to answer, as it’s different for every driver. But what I know is this: If you think about crashing, you’re more likely to crash. You want to think about the act of driving, and not the results (a win, a crash, or whatever).

6 Comments

  1. Ross,
    Kind of a follow-up question to this momentum car post. Does it make more sense for a newer racer to learn with a momentum car so you learn to be as efficient as possible in the turns?

    Reply
    • I sure think it does. Too many drivers begin in fast cars that mask the mistakes they’re making, so they learn less. A momentum car doesn’t do that, so you learn to do things right. That’s why Miatas are so popular.

      Reply
  2. Amen to starting in a ‘momentum car’ coming from one who started in a 914 2.0 to really learn how to drive on the track. Add rain and it really accelerates the early learning curve!

    Reply
  3. Good to have the text book definition of a momentum car. Maybe it would be better to use the term “less power than grip car”? Is there a situation where a lot of power means you can run the fastest lap not minimizing the amount you slow down?

    Reply
    • Well, every “rule” is meant to be broken! Yes, with enough power you could slow the car down a lot, turn it, and then re-accelerate it. I think that’s called drag racing! 🙂

      Reply
  4. Hilarious and useful, if a student ever shows up at a road course with a funny car we can start by discussing late apexes and cornering speeds far below minimum as well alternative race tracks that may be more suitable.

    Reply

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