Taking Weight into Account for Downhill Skateboarding

[thokk2]

Two objects of equal aerodynamics will fall at the same speed. (A ping-pong ball and a cannon ball, if dropped from the same height at the same time will hit the ground at the same time.) But with skating you must also consider rolling resistance and momentum.
A small skater has the ability to get into a very small tuck, but there may be gaps in the tuck. Where as a fat skater may have less holes in his tuck, he may not be able to get very small. So each must find a tuck that is the most aerodynamic for his body.
A heavy skater will compress his wheels more, so needs to ride harder wheels to create less rolling resistance. And a lighter skater can run softer wheels. (I'm not sure how bearings play into this, so I won't pretend I know.)
Therefore, if a heavy rider and a light rider both have equal rolling resistance (by running different duro wheels) and equal aerodynamics (by having different tucks) they would be equally fast, but only in a straight line.
If you introduce any uphill or turns things change. A heavy skater has more momentum, so in an uphill section he will carry his speed farther than a light skater. In a turn a heavy skater will have more speed coming out of the turn than the light rider. But the heavy skater has more momentum and has a higher chance of sliding in a turn, therefore loosing speed and being slower then the light skater who does not slide. This can be fixed by running softer wheels for the heavy rider, but then he will be slower in the straights.
Therefore, weight, if accounted for while perfecting your tuck and wheel shopping, will not affect your speed.



I have no sources on this, it's just theory from my head, so correct me if anything is wrong.


Here's a picture of Brianne Davies.

[zprawn]

i need air to breathe...

[BoardDuDE630]

i like the little treat at the end of the story.


anyway, i totally agree with you man because i have experience all of that. At the second santa fe outlaw, i think it was our heat, me and this other guy who was pretty much the same size as me had to push up the hill while everyone else who was bigger had no problem going up it. Also last saturday a terraza me and jesse were going down, and he is almost exactly 2 of me, i drafted off of him for a bit then went to the side we were goin the exact same speed .
This probly the reason why im able to stick turns on my evo without drifting out (since apparently drop decks are naturally drifty) even with my gumballs that have pretty much no grip left im able to stick corners without it drifting out unless i want it to.


very nice write up devon

[streetheap]

A ping-pong ball will not fall at the same rate as a cannon ball.

[ckpcw]

I have no sources on this, it's just theory from my head, so correct me if anything is wrong.

OK.
The basic premise of your argument is incorrect. That is, unless you skate in a vacuum:

Two objects of equal aerodynamics will fall at the same speed. (A ping-pong ball and a cannon ball, if dropped from the same height at the same time will hit the ground at the same time.)

In a fluid such as air, this is false. The terminal velocity of a bowling ball is much higher than that of a ping pong ball. The higher you drop the objects from, the more pronounced the difference in fall times will be. Also, the "aerodynamics" of a bowling ball and a ping pong ball are not equal - they are both spheres, but have different surface areas.

Since fluid drag in air can be approximated as proportional to velocity squared, the advantage of a heavier rider will become more and more pronounced at higher speeds.

I could go more in depth, but I think I've already nerded out enough.

[tomahawk]

joo thinkin aboot life in a vacoom.

we have air on dis planet. fat people win. or better, more dense people.

[JamieReis]

OK.
The basic premise of your argument is incorrect. That is, unless you skate in a vacuum:


In a fluid such as air, this is false. The terminal velocity of a bowling ball is much higher than that of a ping pong ball. The higher you drop the objects from, the more pronounced the difference in fall times will be. Also, the "aerodynamics" of a bowling ball and a ping pong ball are not equal - they are both spheres, but have different surface areas.

Since fluid drag in air can be approximated as proportional to velocity squared, the advantage of a heavier rider will become more and more pronounced at higher speeds.

I could go more in depth, but I think I've already nerded out enough.

The basis of my argument in the other thread. Regardless, the bigger dudes have advantages in the courses with higher grades.

[NickMoran]

a lighter rider will accelerate faster and a heavier rider will maintain their momentum longer. this much i know is true.

A small inexperienced skater has the ability to get into a very small tuck, but there may be gaps in the tuck.

Fixed it for ya Im a small skater and I have no gaps in my tuck..

[thokk2]

I guess I never took air resistance into consideration. I think in a vacuum apparently.

[guivans]

Instead of everyone stating their thougts on a question that has been debated here thousands of times, it would be much more helpfull to put a link to an article or something, where the situations we skateboarders face was studied, this is, taking into account air resistance, cross sectional area, ground resistance ( influence of weight in the resistance between wheels and tarmac), mass, inclinated plane degree, acceleration and terminal velocity...think thats enough!

[thokk2]

Instead of everyone stating their thougts on a question that has been debated here thousands of times, it would be much more helpfull to put a link to an article or something, where the situations we skateboarders face was studied, this is, taking into account air resistance, cross sectional area, ground resistance ( influence of weight in the resistance between wheels and tarmac), mass, inclinated plane degree, acceleration and terminal velocity...think thats enough!

OK. I'm with you.

I say we go skate and find out who is faster.

[guivans]

Its not about that...go out and skate is good too, but a scientific article that supported some statements would be much helpfull. It would be good to see this question sorted out...

[thokk2]

Its not about that...go out and skate is good too, but a scientific article that supported some statements would be much helpfull. It would be good to see this question sorted out...

It would be, but it will take a lot of research.

I have a friend who is a physics major, I'll see if he knows anything related to this.

[keef]

a lighter rider will accelerate faster and a heavier rider will maintain their momentum longer. this much i know is true.



Fixed it for ya Im a small skater and I have no gaps in my tuck..

That is inertia for you.

But, I think the difference all this sh!t makes, is far out weighed by rider skill, or more importantly lack of rider skill.

[thokk2]

Fixed it for ya Im a small skater and I have no gaps in my tuck..

That's why I said the bold part.

A small skater has the ability to get into a very small tuck, but there may be gaps in the tuck.

[BoardDuDE630]

i say we put this to the test.
we can have me and jesse go down a hill, we both have basicly the same board, and almost same duro wheels or we could even borrow some wheels. His can be harder mine softer and vice versa.

yea??

[thokk2]

i say we put this to the test.
we can have me and jesse go down a hill, we both have basicly the same board, and almost same duro wheels or we could even borrow some wheels. His can be harder mine softer and vice versa.

yea??

It may work, but we would have to put you both in a wind tunnel to see if your tucks are equally aerodynamic.

[guivans]

The main purpose would be a very accurate result...not some kind of homemade experimentation...
To that, we have cases like Teutonia, wich is mostly straight course, and where Kevin, Scoot and many others can keep up with a bigger heavier guy like Dalua.
I think in the end, the things will be pretty similar...

But what would be good was some supportive math and physics.....

[BoardDuDE630]

It may work, but we would have to put you both in a wind tunnel to see if your tucks are equally aerodynamic.

im gonna go out on a limb and say no

damn almost had it

[sterlingc]

It may work, but we would have to put you both in a wind tunnel to see if your tucks are equally aerodynamic.

and even then its mostly paper racing,

what happens when road conditions change?

what happens on a bendy course when you're spending hardly any time in a tuck and transitioning all the time?

I think this sort of paper racing rarely ever translates into reality.


lets say we all find out fatties are faster, are you gonna start eating more cheeseburgers?