Are Heavier Skiers Faster? (Drag, Resistance & Gravity)
Following the law of gravity, heavier items drop at a faster speed. That's just common sense. But when skiing down a slope, does a heavy skier go faster than a light skier?
As it turns out, yes, a heavier skier will go faster thanks to how gravity works. Being bigger will produce more drag and resistance which can also slow you down. Together gravity, drag, and snow resistance will determine your speed.
There is a breakpoint to achieve maximum speed, as going above it nullifies the benefits of a heavier mass thanks to the greater snow resistance.
Let’s discuss how a skier’s bodyweight affects their speed, the physics behind it, the point where being heavier actually makes a skier go slower, and other stuff to keep in mind for the speed demons out there.
The Physics of Ski
There are a number of forces that are affected by the skier’s weight in relation to how fast they can go down a slope, such as:
Let’s start with gravity that pulls us down. When you’re standing on a slope, this downward pull effectively makes you move forward, thanks to the combination of your weight and the slope’s gradient. To put it simply, the heavier you are and the steeper the angle of the slope is, you’ll go faster, but simply being heavy isn’t enough to win races, because a heavier skier generally has a bigger frontal surface, which affects our second force - drag.
2. Drag / Air Resistance
When moving, our body experience resistance from air. As heavier skier tends to have a larger surface area, they will be more affected by the drag, which can slow the skier down. If you stop and think about it, that’s why airplanes have a small, tapered frontal area to minimize the drag, thus making it easier for them to move faster through the air.
While a heavier weight will generally offset the drag coefficient and still make them ski down a slope faster, even with the greater air resistance, it can affect the third force in the equation - snow resistance.
3. Snow Resistance
Similarly to air resistance, we want to minimize the resistance created by the friction of the skis and the snow surface. Less friction equals less resistance, but as our weight goes up on the scale, the gravity will pull us down, thus creating greater friction and snow resistance that can potentially hamper the skier’s speed.
Longer skis can help to spread the weight per square inch more evenly to reduce the resistance created by the snow surface at the cost of less agile turns.
It’s believed that 200 lbs (90 kg) is the breakpoint to achieve maximum speed, as going above it nullifies the benefits of a heavier mass thanks to the greater snow resistance.
4. Thermal Energy
We’ve acknowledged that less friction is better for you who wish to achieve greater speed while skiing. But too little friction won’t help you to reach that speed you’ve been craving for. When you’re standing on a ski slope while wearing your skis, the gravity pulls you down to keep the ski and snow surface in contact. This creates friction and ultimately, heat or thermal energy.
The heat generated creates a layer of melted snow that lessens the grip of the skis on the snow, thus making you slide. On softer powder snow, the snow melts easier when it comes in contact with the ski to make it easier for you to move.
How to Maximize Speed and Other Things to Consider
We’ve discussed the forces that affect how fast you go when skiing. Now, for you who crave to go even faster, here are some factors to keep in mind to reach that exalted speed:
Alpine or downhill skiers usually ski in a crouch position to make their projected frontal area smaller. This means less air resistance that acts as a natural break, and as a result, the skier will go faster.
2. Ski Suit
Choosing the right ski suit can help to reduce drag by streamlining the figure and minimizing creases and folds. A downhill ski suit usually has a smooth surface texture with minimal seams to ensure that air flows as smoothly as possible over the body.
3. Wax Your Skis
Waxing your skis regularly can keep them at peak speed while helping to protect the edges from rust and chip. While we’d advise you to treat your skis to some wax at least once a year, if you ski regularly, you’ll need to wax your skis once a month, maybe more depending on how often you’re racing down the slopes.
Wax adds a hydrophobic layer to your skis, which can help the melted snow beneath the skis speed you up instead of acting as a resistance. It also helps to fill the pores on the ski base to keep you gliding down, instead of trudging down, the slopes.
4. Choose Your Skis Wisely
Not all skis can handle the breakneck speed that you’re aiming for. A heavier skier may want to grab a pair of longer skis to help spread the weight evenly on the snow surface, so they can glide on top of the surface instead of digging into the snow. This ski chart offers a good insight into how long a person in a certain weight range might need. Some may push the length of the skis even up to 220 cm (87 inches) to spread the weight even more evenly, although it’s good to remember that longer skis need more skills to control.
The flex of the skis also plays a big part in generating speed and control. In general, a light skier may benefit from a more flexible ski and vice versa. The stiffness of the ski helps it to adapt to the terrain surface as well as determine how much bend it gives in the middle of the ski when weight is applied.
Heavier weight equals greater speed while skiing, although there’s a limit at around 200 lbs, and going above it actually introduces more friction on the snow surface that can slow you down. It’s also important to remember about physics behind skiing and how you can maximize them in order to achieve the speed that you’re aiming for. Now, you’re ready to go even faster than before.