fundamentals of downhill

Fundamentals of downhill:
Including lessons to be learned from alpine skiing.

I have to admit, I’ve never been skiing, so I can’t claim to be any good at that. However, if practice makes perfect, then one thing I must be good at is watching TV in the off season. Sometimes you learn things, and it makes the approach to your bike more deliberate. This is one of those things.

Between events on … hmm… I’ve forgotten whether it was World Cup or Olympics… there was a segment prepared that showed how the world’s top skiers can go downhill faster than others with the same physical stature, the same equipment, and the same drive to win.

It turns out, the same is true on a bicycle.

You can be faster than people who are fitter, heavier and stronger than you!

A little background about me. I’ve got a solid set of downhill skills, and regularly outrun guys on aero bars, short wheel-base recumbents..even some tandems on downhills.

When you’re going downhill, its all about confidence, bike handling and your position on the bike. So, let’s first revisit the fundamentals of a good downhill position, then we’ll look at how specifically thinking like a skier can make your downhill faster, and perhaps even SAFER at high speeds.

THE SIX ELEMENTS OF THE BASIC TUCK

  1. Shoulders and head low, with a flat back
  2. Feet high and parallel (at clock positions 3 and 9)
  3. Butt OFF the saddle
  4. Knees together
  5. Forearms parallel to the direction of travel (straight* and level)
  6. (*optional hands close together on the bar)

I think I put those together in order of importance. Here’s why (or you can skip ahead to the skiing connection, below):

1) Low shoulders is kind of obvious. If you can get put them straight ahead of your hips, that’s the biggest thing you can do to reduce your “cross section,” the largest factor in wind resistance.

2) Parallel feet may actually be more about getting your thighs into the best compromise. Theoretically, without taking your feet off the pedals, you could get one thigh closer to horizontal, but the loss in streamlining of the opposite (vertical) leg loses more than whatever you would gain with one leg up

3) Butt off the saddle seems like a nuance, but this helps the overall position immensely. If you’re trying to lower your shoulders as in element 1, eventually, you can get them so low that your elbows drop below your hands (element 5). Since your feet are already level from element 2, they’re in perfect position to take your weight off the saddle.

4)  A little pressure from the inside of your thighs on the saddle or top tube helps you establish a 3-point plane of contact with your bike — essential for complete control. I’m not sure if knees together is really more aerodynamic, as far as creating a wedge shape from your thighs, but bringing them together will help you feel more solid, and you’ll get over the funny feeling of having your butt off the saddle in no time.

5) Forearms parallel to the ground makes a difference you can hear! Those of us that are lucky enough to remember some things from high school science classes remember that an efficient device is one that creates the least kinds of extra energy. For instance, if you have a noisy window fan, part of what you’re spending your electric bill on is the production of that noise. An efficient window fan spends more energy moving larger volumes of air, and less energy vibrating it in the process. See what I mean? (Same thing with a well-oiled chain. If it’s making noise, that’s a tap on your power production.) When my elbows are too low or too high, I can hear the wind off my forearms at high speed, which means they’re not just aerodynamically out of alignment, but the noise itself is slowing me down.

Remember sticking your hands out the window of a car when you were a kid. When we’re approaching highway speeds on a bicycle, all those forces are the same as the ones on a car. Bringing your elbows in front of your torso makes it so they aren’t “hanging out the car window” as it were. You won’t likely feel the difference in air pressure on your biceps, because they’re still breaking the wind — blocking it from in front of your less-sensitive hips and thighs.

6) OPTIONAL — this is a LOOK MA, NO BRAKES advanced skill for longer straightaways. It’s a bit of a paradox, that by giving up control, under the right circumstances, you actually get more of it. If you’re doing element 5 right, and you’ve found the quiet position of forearms, hands on the brake hoods is a really efficient place for them. Hands-in-front-of-biceps-in-front-of-hips. That’s all good. By bringing your hands together on the top of your drop bars, you sacrifice a little of that efficiency and almost all of your direct control of your handlebars! What you gain, is a slightly different kind of aerodynamic envelope — PLUS – when you trade in steering for control by leaning, you factor out the friction that happens when your tires are facing different angles.  Here’s where the connection to skiing is really obvious. You wouldn’t want your skis facing at different angles.

THE SKIING CONNECTION

I had been practicing the 6 elements of a tuck for … I don’t know… maybe 20 years, before I saw that thing on downhill skiing. The narrator guy says that while it looks like the guys who are flying through the air must be going faster, their times over the finish line tell a different story. The reason is one of those efficiency things. It turns out that if you hit a bump hard enough to catch air, the bump already slowed you down. Plus, by changing your trajectory to something more shallow sloped than the snow, you’ve lengthened the overall distance you need to travel to get down the mountain.

So they show top top-level skiers hitting this bump in a split frame, and the one who catches air is obviously going slower by the time they hit the ground. How does the faster person hit the same bump at a higher speed and not catch air? They absorb it with their legs!

Okay, so let’s go back to element 3 of a conventional tuck, above — butt OFF the saddle. It turns out that this not only helps put your hips up behind your shoulders, but it also makes it so that your legs can absorb the bumps and unevenness of a surface, and let your the rest of your mass travel in the straightest line down the slope.

I said I had been doing this for like 20 years, but after I saw the skiing thing, it took me a little while to make the connection. Turns out, I had gotten into a habit of descending while seated. Perhaps I was lazy, perhaps I felt more in control… I don’t know. Little-by-little, one summer of long-way-home commuting, I started working on getting my good habits back by focusing on fundamentals, and when that thing about downhill skiing clicked in my head, suddenly it all came together. By taking my butt off the saddle and lightening my grip on the bars, I was able to let the bike do its own thing and let my mass go down the hill.

Wait, you said “safer”?

Yeah. I actually feel safer with my hands off the brakes. When I’m squeezing out the difference between going 53 and 55 mph on a downhill, having my butt off the saddle means I’m not going to feel like I’m going to endo every time I hit a pebble, and the same thing goes for my bars. If I can push the handlebar down the backside of a hump and keep the tire on the ground, that’s a good thing. For some reason, that pushing movement feels more natural to me with my hands closer together.

THE OTHER SKIING CONNECTION

Although I’m mostly talking about the tuck, skiing techniques also help in cornering. When you’re coming into a corner where you have to come out of your tuck, get your hands back out to the brake hoods, drop your outside foot and put all of your weight on it. Slide your weight back a little, and let the bike “carve” the turn.

Nothing against bunny hops.

Above, I qualified my downhill position as a conventional tuck. I have tried the uber-forward sternum-on-the-stem tuck. It’s not for me. It takes a lot of strength to hold it on long descents. I also employ a kind of hybrid weight-back position like mountain bikers do an extremely steep downs, but it’s rare that I move back far enough to put my belly on the saddle. I do bunny hops, too…. but again, that’s sort of not what I’m talking about. Lifting your tires off the pavement has its own place, to keep from crushing a rim, or hitting railroad tracks that would send your tires in the wrong direction.

Like any other skill, you can take this on one step at a time, or on short stretches of downhill. I think if you follow my suggestion and think of your descents like you’re an Olympic skier, you might find your own sweet spot a little sooner.

–Robert Jackson

 

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