The value of weight, or lack there of...

[Alien]

Bryan knows that too. Just look at his Pinwood Derby trophies.

[AllZWay]

Bryan knows that too. Just look at his Pinwood Derby trophies.

And everyone knows you can't win a Pinewood Derby without cheating the rules.

[BryanL]

Al-if you weren't busy playing with gerbils you might know that I am at my minimum weight. But also my car isn't one of those illegal LAW cars.

Pretty tough to cheat in Pinewood unless you have someone on the inside but I sure was accused of it by all the Texas Instruments engineer dad's that were making wheels on the lathe and building computer models at work. I built my car when my older brother was in cub scouts and that car would kill everyone at the test/tune night. I ran a different car the first year that got 2nd but was slower then "The Mongoose".

Ken-how in the world do you get your car to have wheelspin?

[marshall_mosty]

Weight can be viewed several ways:

1. It takes horsepower to accelerate additional weight.
2. It takes more brakes to deccelerate additional weight.
3. Tires have more ultimate grip with more weight (static weight plus downforce), as the traction force a tire can produce is the coefficient of friction of the surface times the vertical weight applied downwards on the tire.

#3 is the most interesting as you will also put more heat into the tire with more weight. As long as you don't exceed the operating temperature of the tire, you are at a benefit. The moment you overheat the tire, you lose out on the benefits of the weight gain.

4. Weight can hurt you in the corners if it's located above the cars C.G. as it transitions weight more drastically off the inside tires than weight at or below the C.G.

5. Weight below the C.G. will have a self leveling effect, trying to upright the car in a corner. This is good to put weight on the inside tires as well. More contact patch, more sq. in. of rubber on the surface = faster corner speed.

So, to summarize, if you are already overheating the tires, you need to LOSE weight or get a wider tire. If you are not able to get the tires up to temperature, you can add weight or get a narrower tire.

On a side note, we didn't talk about the horsepower required to accelerate a heavier (wider) tire/wheel versus a lighter (narrower) tire/wheel, the extra braking required to stop the rotating inertia of the heavy (wider) tire/wheel versus the lighter (narrower) tire/wheel, or the aero drag of a wider versus narrower tire which takes more horsepower to accelerate. That's a different lesson for a different day.

[kbrewmr2]

Ken-how in the world do you get your car to have wheelspin?

Open Diff + Body Roll

It is pretty torquey for the small amt of horsepower it makes too

[BlueFirePony]

On a side note, we didn't talk about the horsepower required to accelerate a heavier (wider) tire/wheel versus a lighter (narrower) tire/wheel, the extra braking required to stop the rotating inertia of the heavy (wider) tire/wheel versus the lighter (narrower) tire/wheel, or the aero drag of a wider versus narrower tire which takes more horsepower to accelerate. That's a different lesson for a different day.

Or the time it takes to for a heavier (wider) ass to egress the car ....