Is there a time disadvantage for heavier drivers in go-karting?

January 7th, 2007 • Related • Filed Under
karting
berger070 asked:


What is the approximate lap time disadvantage (e.g. 0.5 seconds, 1 second, 2 seconds etc.) for a 200lb (90kg) driver compared to a165 lb (75kg) driver on a typical 30 second indoor go-kart track with both drivers in identical 6.5hp go-karts?

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There Are 5 Responses So Far. »

  1. Comment by whata.crock on 8 January 2007:

    I’m not a math or physics guru so I won’t even attempt to find the formulae and numbers. But what I can tell you is that there is a definite disadvantage to heavier drivers provided that the skill of the drivers and the karts are identical. Perhaps someone else here can tell you by much of a difference.

    As you may know, speed is based on horsepower-per-weight ratio. The higher the ratio, the higher the speed will be. The higher you weigh the lower the horsepower-per-weight ratio. Hence, your overall speed will be slower. There is also the principals of inertia and momentum. A heavier mass takes longer to accelerate and longer to slow down. So in order to take those tight turns the heavier driver has to slow earlier; which, as you know, kills your lap time over someone who can brake later. Also the lighter driver will be able to accelerate off the corner faster which will allow him to gain a higher speed at the end of the next straight.

    So those are the basics. We just need a math guru to plug the numbers in.

    EDIT:

    Let me just add that your weight example is a difference of almost 18%. If the horse-power-per-weight ratio difference directly corresponds to the speed then the lighter driver should be 18% faster. Just think of all the other motorsports that would kill to shave 18% of their weight.

  2. Comment by Ed P on 8 January 2007:

    Yes their is a distinct disadvantage–More weight equals slower times. Real simple Put a 130 Pound racer in a 500 Pound Cart let him run flat out–never lifting—Then put him in a 800 lb Cart with the same size CC engine and see which is faster—–Lighter is better For Car or Driver!!!!!!

  3. Comment by christos_swc on 9 January 2007:

    Impossible to give an exact figure.
    I would think around 3 quarters of a second.
    In the Easykart World Finals in 2007 Heavy and light categories were separated by 0,7 sec around a typical 45 second lap track.
    The difference in weight is 10 kilograms.
    This is a good example because rules are very strict and karts use fixed gearing.
    This means that heavy drivers can’t use shorter gearing to compensate for extra weight and laptime differences indicate the difference caused by the extra weight.
    There’s no formula to calculate time loss per kilogram.
    In the case of low power karts I would expect weight to make a bigger difference because of lack of power.
    That’s why I would think around 3 quarters of a second around for a 30 second lap.
    This is offset somewhat by the fact that 4 stroke hire karts are much heavier than Easykarts that weigh just 80 kilograms without driver so any extra weight increases total weight by a smaller percentage.

  4. Comment by Jay on 9 January 2007:

    There is a definite disadvantage racing with extra weight, but many kart classes are divided up by weight. On a really slick track, the weight could actually be an advantage by adding more downforce and keeping the kart from sliding around.

  5. Comment by dirtkart94 on 10 January 2007:

    I race go-karts on an 1/8 mile dirt oval. I weigh light weight person and I race agianst heavier people and sometimes lose. Try shifting the weight on your kart by using lead weights. You know that you have to scale the kart, right?. Try different setups. Try posting a question a sign up for a membership at for more tips.

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