All information on this page provided by Skateboardracer.com and Exploratorium.edu
Information:
The History of Skateboarding
The Science and Art of Skateboarding Design
The Physics of Skateboarding Tricks
Physics Terms Glossary
Back to Main Page
Skateboarding, a young sport of which no one truly knows the origin. Many stories revolve around the invention of skateboarding. Some believe that skating began on the surfing beaches of California, USA in 50's by surfers who put rollerskates on surfboard. At first boarding was known as a type of sidewalk surfing which was done when the waves were to small to go out surfing.
The origins of skateboarding are reflected in the design of the earlier skateboards which looked like surfboards. The boards were narrow (4in, 10cm) and much shorter than boards now and the 'sidewalk surfers' from the 50's would ride in bare feet and in more sideways stance than we do today. All they would have been able to do is ride up and down sidewalk and turn by leaning in the direction they wanted to go.
The first manufactured boards came in 1965. They were inch-thick wooden boards, with narrow cast-iron trucks and hard rubber wheels. Soon, races down the sidewalk began to vary and competitions between skateboarders were born: free style, slalom, downhill, high jump and long jump.
In the mid-70's skaters started using drainage channels and routes up the slopes around buildings for skateboarding. This opened up the new world of tricks. Skateboarders soon discovered bank skating and they soon were able to manoeuvering their bodies more skillfully. Vert skating then began by using back yard swimming pools. All you needed was a little but of extra speed and you could ride your board up the wall, or so they thought. It was a bit more complicated than that. 1) Pool owners didn't like their swimming pools being used for skateboarding 2) Pools weren't rounded enough. Transitions were to vertical to fast and it would launch them into the air, and even if they could stay on, they would not have enough speed to get up the other side. Skateboarding quickly developed in the US and soon skateparks were built. Pools were built with more rounded sides and then lay-outs for bank and freestylers were built.
Until the early eighties, parks were the main hang-out for boarders. Competitions and tournaments were organized for them and soon pool and vert skating became the most popular specialist form of boarding. Vert skating was most spectacular of the forms. It was incredibly difficult and demanding, which encouraged more changes to be made on the skateboard. The manufacturers built them wider for better stability and changed the old rubber wheels with polyurethane wheels which proved to be faster and had more grip as well. Barefoot skating was now forgotten except by a few of the old die-hard 'sidewalk surfers'. The new skaters figured out that gym shoes had more stability and didn't hurt as bad when you wipe-out.
In 1980 skateboarding arrived in Europe, where free style, slalom and high jump became the disciplines of choice. But in both countries it was still considered to be just another craze that would pass so it was not considered to ever be a competitive sport. Early eighties arrived with a dive in the skateboarding popularity. It happened almost within a single season. Skateparks closed the doors, manufacturers stopped manufacturing, and worst of all, skateboard magazines switched over to BMXing and rollerskating. But a few hard-core skaters kept on going in both of the continents. Those dedicated skaters advanced skateboarding by creating their own techniques, writing their own magazines, and building some of their own boards and layouts.
This was when half-pipes arrived. Simpler and cheaper than pools, they could be built by the skater himself. Half-pipes were usually built of wood and were U-shaped with a ten-foot radius transition on either side with a flat area in the middle, large enough to give you time to concentrate and get speed before hitting the transition.
Boarding became unpopular with the public, which in turn pushed the skating scene 'underground'. This might have stifled it but because of the small, but committed group of skateboarder, the sport entered it's most creative stage. Skaters became so envolved with their sport that they wanted nothing else. It was not really a sport, but was becoming a life-style. If not for the commitment of the few, this sport could not have survived the hard times.
Skateboarding soon became a mode of transportation. Skaters would go through any and all obstacles in their path. They could, and would, bring their boards anywhere and everywhere. In the early 80's, street skating was born. This new art was free of half-pipes and parks, the skater could DO what he wanted ON what he wanted. Tricks were used in street skating that, before, had only been used by vert skaters. Street ollies, slide'n'rolls, and kerb grinds (most of which have different names now) are classic as street skaters moves, all of which were made by vert skaters.
Street skating is still probably one of the most popular forms of boarding. Every skater is a street skater because that's where his roots are from. It's just that some skaters forget a few things along the way.
The Science and Art of Skateboard Design
In the begining skateboarding was easy...
With nothing more than a two-by-four on roller-skate wheels, the sidewalk surfers of the 30s, 40s, and 50s had a straightforward mission: Start at the top of a hill and ride down. The primary goal was just to stay on and avoid collisions; given the humble equipment and rough road conditions, it was no small challenge. Now, thanks in part to improvements in design and materials, skateboarders have a higher calling.
What is a skateboard?
Is it just a glorified plank with roller skate wheels on it? Or is it a highly engineered device through which kids have reclaimed the urban landscape, bringing creativity and style back to the sterile asphalt spaces of sprawl?
The basic elements of the skateboard seem pretty straightforward. A board has three parts: the board or deck, the wheels, and the trucks, which connect the wheels to the board, and allow the board to turn.
Boards, wheels, trucks
But how do you get from this relatively simple mechanism to the perfectly balanced vehicle, the tool for endless creativity on the ramps and streets? We talked to two of the leaders in the design and production of skateboards, Tim Piumarta of NHS Inc., and Fausto Vitello of the Ermico Foundry, manufacturers of Independent Trucks, to find out about the mixture of industrial science and "feel" that goes into a great board.
Plank, deck, or board: whatever you call it, wood is the thing
Tim Piumarta has been one of the most influential skateboard gear designers over the past 20 years, as the R&D guru of NHS, creators of Santa Cruz Skateboards, Road Rider Wheels, and much more. He described to us the process of making a modern skateboard:
Why maple wood? Piumarta described the unique characteristics of wood. "With all the alternate materials we've tried, from epoxy and fiberglass to carbon loaded thermoplastic nylon, nothing has had the combination of toughness, elasticity, feel and response of laminated sugar maple board."
Concaves, kicktales, nose
Piumarta was one of the first designers to put concave curves into boards in the early 1980's, and developed the first upturned nose. When skaters refer to "concave" they are talking about the way that the board curves up at its edges, nose and tail. This curvature both strengthens the board and gives the rider more control of the board.
The other shape is called the plan form. This is the shape of the board's outline; if you put a board flat up against the wall and traced its outline, you would be drawing the plan form. According to Piumarta, this shape is largely determined by the choices of individual riders. "Now the other shape we're talking about is the plan form, or the shape outline of the board of looking at a wall. Pro riders can tell by looking and feeling with their hand, they can tell if a board is out of shape by even fifty thousandths of an inch. They can feel it, they know what they like, and what they don't like." And, as Piumarta says, all the engineering in the world means nothing if it doesn't result in a good ride.
By Noel Wannar
"Modern skateboards are made traditionally from 7 plies of sugar maple veneers, pressed together using polyvinyl glues in either aluminum, metal or concrete forms, generally taking around 300 psi to take up multiple skateboards in one closing of a press. Anywhere from 3-5 skateboards are done in one press, and after 30 minutes to an hour, the boards are removed from the press. At this point they have been stuck and laminated in the compound curve or the shape, which is the concave. Then after days of curing, the CNC routers, or hand routers depending on the woodshop, will cut out the final shape, apply the edge trimming, paint it and send it on its way."
"There's two shapes you talk about when you look at performance: of a skateboard: number one is the concave, the 3-dimensional curves that are in the board itself, nose, tail and side to side concave. Every manufacturer has their own style or philosophy. Mine is based on actual functionality; what your foot feels like when it's in the concave itself. To get there, I do a lot of prototyping in foam cutting, letting all of our pro and amateur riders have a say in what feels good and what works before we go and cut tooling to make skateboards. So our approach is based on a feel functionality first, and then secondly, when no one's looking, I slip in curves and bends engineered into this 3-d curve, the concave, that makes the board stiffer, stronger, and makes it last longer."
Frontside Forces and Fakie Flight:
In a blur of flying acrobatics, skaters leap and skid over and onto obstacles, executing flips and turns of ever increasing complexity--all at top speeds. For onlookers and beginners, it can be hard to follow the action, let alone answer the question that springs naturally to mind: How on earth do they do that? While it may seem that modern skateboarders are defying the laws of physics, the truth is that they're just using them to their advantage. Let's take a closer look at some fundamental skateboarding moves and the physics principles behind them.
Jumping: The Ollie
Invented in the late 1970s by Alan "Ollie" Gelfand, the ollie has become a skateboarding fundamental, the basis for many other more complicated tricks. In its simplest form, the ollie is a jumping technique that allows skaters to hop over obstacles and onto curbs, etc. What's so amazing about the ollie is the way the skateboard seems to stick to the skater's feet in midair. Seeing pictures of skaters performing soaring 4-foot ollies, many people assume that the board is somehow attached to the skater's feet. It's not. What's even more amazing about the ollie is that to get the skateboard to jump up, the skater pushes down on the board! The secret to this paradoxical maneuver is rotation around multiple axes. Let's take a closer look.
Mid-Air Maneuvers
A skateboarder launches straight into the air from the top of a ramp. Seeming to hang in place for just a moment, he turns in midair and directs himself back down the ramp. Skaters call this maneuver a frontside 180. Physicists call it impossible.
Well, they don't really call it impossible. Just very, very sneaky.
You see, one of the fundamentals of physics is a little something called the law of conservation of angular momentum. This is what it says: If you're rotating, you'll keep rotating unless a twisting force, or torque, acts to stop you. Likewise, if you're not rotating, you can't rotate unless a torque starts you rotating. Seems fair enough, right? There's just one more important detail. If you're in midair, the only force that can act on you is gravity. On earth, gravity can't make you rotate; it can only make you fall. So the question is, how does a skater go from not rotating to rotating, without the help of an external force?
As it turns out, skaters rotate in midair using a trick borrowed from housecats. As you rotate your legs 90 degrees beneath you, your arms and torso rotate in the opposite direction. You probably found yourself naturally sticking your arms out as you turned—this increases the rotational inertia of your upper body. The upshot is that a large rotation of your legs is exactly cancelled by a small rotation of your outspread arms. Since the two rotations cancel, angular momentum stays constant at zero, and the law of conservation of angular momentum is satisfied. (Whew.)
In much the same way, skateboarders turn in midair by twisting their arms and legs in opposite directions. Upon landing, a skater can use the friction between his or her feet and the skateboard to twist the upper body back into alignment.
Believe it or not, this is exactly how a cat always manages to land on its feet. By extending and retracting its front and rear legs, the cat changes its rotational inertia. While falling, the cat extends its rear legs and twists the front half of its body toward the ground. The rear half rotates in the opposite direction, but not as far. Then the cat extends its front legs and twists its tucked rear legs toward the floor. By repeating these motions, the cat gains sufficient net rotation to guarantee that its feet point downward when it strikes the ground.
Half-Pipes: Pumping for Speed
Skateboarders in half-pipes have a need for speed. The faster they go, the higher they can rise out of the pipe. Achieving greater heights is not only impressive on its own, it's necessary for pulling off acrobatic tricks like Caballerials and McTwists.
On flat ground, the conventional method for gaining speed is to push off with one foot. But half-pipes present a much more elegant option for the speed-hungry skater. It's called pumping. To pump in a half-pipe, a skater first drops down into a crouch while traversing the flat bottom of the U-shaped pipe. Then, as she enters the sloped part of the ramp, called the transition, she straightens her legs and rises up. By raising her center of mass just at the beginning of the ramp's arc, the skater gains energy and thereby increases her speed.
Pumping in a half-pipe is closely related to pumping on a swing. To get the swing to go higher, you lift your legs as you pass through the bottom of the swing's arc, then drop them at the top of the arc. Each time you do this, you gain a little energy and swing a little higher.
From a physics point of view, the extra speed that comes from both kinds of pumping is a result of the equivalence of work and energy. As you move into the bottom the arc, centripetal force makes it harder than normal for you raise yourself. The net work you perform in lifting yourself is equivalent to a net energy gain. This energy gain translates into extra speed and greater height at the top of the swing or ramp.
The Physics of Skateboarding Tricks
By Pearl Tesler and Paul Doherty
Physics Terms Glossary
centripetal force: a force that keeps a body moving in a circular path
rotational inertia: a measure of an object's resistance to being turned, depending on both the mass of the object and how that mass is distributed
work: force applied over a distance-for example, you do work when you push a box across the floor, but not when you push on a locked door; work done on an object or system results in an increase in the energy of that system