Aerodynamics Part 2: Small Things That Reduce Air Resistance and Drag

PIC372688193Tony Martin won the UCI World Time Trial Championship in 2011, 2012 and 2013, and is the odds on favorite to win it again this year. He is an incredible bike rider and by all accounts an incredibly nice guy; he once caught and passed David Millar in a time trial and apologized to Millar as he went by. The picture is of Martin time trialing in full aerodynamic mode at the 2013 Criterium du Dauphine which is an eight-day race that Martin won on the basis of the insurmountable lead he built by winning the time trial.

If you want to minimize air resistance and drag as much as possible, you ride like Martin rides in a time trial. Unfortunately, this is beyond the reach of many riders for a number of reasons. First, it’s expensive. Between his bike frame, wheel set, skin suit, helmet, etc., Martin is moving well over $10K worth of gear in the photo. Next, an optimized wind tunnelaerodynamic position is difficult to accomplish. Differences in body mass and shape mean that the position that optimizes both aerodynamics and power output is different for every rider. Finding that position takes hours of iterative testing and refinement in a wind tunnel. In addition, a full aerodynamic tuck is difficult to maintain and usually takes many hours of practice to be able to hold for any length of time. Simply strapping a set of aerobars unto your bike isn’t going to do it. Finally, riding in an optimal aerodynamic position is difficult. The position is uncomfortable and the bike is more difficult to control when you’re stretched out on aerobars.

Although going full aero involves a significant investment of time, effort and money, there are a number of simple things you can do that will reduce air resistance and drag that are relatively easy and are either free or cost the price of a new jersey. Taken individually, none of these things will result in a huge reduction in air resistance but small things add up and they can make a noticeable difference over a long ride.

Get Low

The biggest single thing you can do to reduce air resistance without spending any money is to reduce the surface area on the front of your body that is exposed to the wind as you ride forward. It’s easy to do and you don’t need aerobars to do it. Bend at the waist and lean forward. The lower you get the better off you’ll be but almost any degree of forward lean will reduce the area of your torso that is exposed to the wind.

Tour of the Battenkill 2012This is easiest to do if you have road handlebars on your bike. Moving your hands from a position on the flat upper bar on either side of the stem to the brake hoods will bring you down a little bit. Keeping your hands on the hoods and bending your elbows will bring you down more. You can get fairly low with your hands on the brake hoods by bending your elbows to the point where you’re resting your forearms on the handlebars like the rider in the picture. You can usually get even lower by riding with your hands on the drops.

Elbows and Knees

PIC298104874While the exact elbow position for optimal aerodynamic riding depends on the rider’s body size and shape, it’s generally the case that tucking the elbows in is better than bending them out. Many riders, however, tend to bend their elbows out in a variety of circumstances. When you bend at the waist and lean forward to get low, make sure to pull your elbows in rather than bend them out. People also tend to bend their elbows out when they are leaning into a climb, working hard to maintain a strong tempo, gripping the bars tightly, or are just tired. Pay attention to where your elbows are and if they are flaring wide, bring them in.

Knee position is an aerodynamic factor that people sometimes miss because it’s usually not obvious in pictures of riders who are time trialing. Take a look at where your knees are relative to your body while you’re pedaling. If your knees are spread open so that they form a V-shape with your body, your legs are funneling air into your body and increasing the air resistance and drag you have to overcome. Ride with your knees pulled in toward the top tube on your bike. Obviously, you don’t want your knees banging into the top tube but closer to the tube is better than further away. When you do this, don’t accomplish the “knock-kneed” position by flaring your ankles out.

Your Jersey

Wear a tight jersey. If your jersey is loose or baggy, it is catching the wind and increasing air resistance by acting like a sail that is pulling you in the opposite direction. Don’t worry about what you look like. How you look in your exercise clothes may be a big deal for gym bunnies but for riders the big deal is how smart and how well you ride. If you’re overweight, you’re overweight; there are things you can do to change that but wearing a loose jersey isn’t one of them. Don’t worry about it. Ride smart.

???????????????Keep your jersey zipped up. Partially unzipping a jersey allows air to circulate around the upper body to the back where it is trapped by the jersey. It’s like strapping a sail facing the wrong direction on your bike. You would think this would be a no-brainer but you see riders all the time from beginners to pros who have expensive aero gear on their bike and who are trying to go fast with their jersey partially unzipped.

 

watts and wind resistence_ key pointsThe graph discussed in Aerodynamics Part 1 illustrates that air resistance is negligible when you are going slow but it quickly ramps up with velocity until it becomes the overwhelming force you have to overcome to move your bike forward. While all of the tips and techniques offered in this post have a small effect in reducing air resistance they are all easy to do. They are also either cost-free or cost, at most, the price of a new jersey. Small benefits add up and their combination can make the difference between a ride that is exhausting and a ride that is exhilarating.

Hill Climbing 102: Riding Techniques

This is one of a pair of posts designed to help new riders climb.  I looked at pedaling and shifting in Hill Climbing 101.  In this post I’ll examine some riding techniques that can improve your ability to climb hills.  Part of the climb up the Col du Sarenne, the back route up to l'Alpe d'HuezThere are many different approaches to climbing and riders at different stages of development will tackle a climb differently.  A new rider who is desperate to survive to the crest will climb very differently from an experienced racer trying to drop the competition on the steepest part of the climb.  Hill Climbing 101 and 102 are written for the relatively inexperienced cyclist who might benefit from some information about basic climbing techniques.

Drop your heels.  To get a sense of what this feels like, move your leg so that your foot is at the bottom of the pedal stroke.  With your foot in this position, keep the ball of your foot motionless on the pedal and tilt your foot so that your heel is lower than your toes.  You’ll feel the stretch in your calf muscles and achilles tendon.  Try and keep your foot in this position all the way around the pedal stroke but especially on the downward push.  Keeping the heels low brings more of the hamstrings (the muscles in the back of the thigh) and glutes (the muscles in the butt) into play.  These are very powerful muscle groups – use them to get you over the hill.  Pedaling with the heels dropped is relatively easy when your feet are attached to the pedals by clipless pedals.  It’s much harder to do, but still possible, if you are using basket-style toeclips or no clips at all.  Many riders tend to point their toes downward which puts less stress on the hams and glutes and more on the quadriceps (the large muscles on the front of the thigh) and calves (frequent calf cramping is a good indication you’re pointing your toes down).  This tendency can be accentuated by the use of toeclips.  If you’re doing this, try to break the habit and drop your heels when you climb. 

Change working muscle groups.  As you labor up the hill the muscles you are using will become exhausted as waste products produced by your straining muscles accumulate faster than they can be carried away in the bloodstream.  It doesn’t take long to clear these waste products if you can make less use of the muscles for a moment.  You can’t coast on a climb, however, because you’ll lose your momentum or come to a dead stop.  The solution is to briefly work different sets of muscles throughout the climb to give particular muscle groups precious time to recover.  There are several ways to do this.  If you typically ride with toes pointed down or feet flat, drop your heels for a bit to bring your hamstrings and glutes more into play and give your quadriceps and calves time to recover.  Likewise, if you usually ride with your heels dropped, raise them so your feet are flat or point your toes down thereby taking the load off the hams and glutes and shifting it onto the quads and calves.  Shift forward and back on the seat.  Sitting on the front of the seat accentuates the quads, sitting on the back accentuates the hams and glutes.  Stand up for a brief interval and then sit back down.  Just before you stand, shift into a bigger gear and then shift back to the smaller gear when you sit down.  You will have more power when you stand and if you stay in the smaller gear you will lose momentum.  Use these techniques for 10 to 30 pedal strokes periodically throughout the climb to buy recovery time.

Remain seated while you climb.  Standing is terrific for short bursts of power or for a change in muscle use (and hence a bit of muscle recovery) on a very long climb.  However, it is less efficient than sitting and will tire you out faster in the long run.  You will be stronger at the end of the ride if you climb sitting at the beginning.  Less efficient to begin with, standing becomes much more inefficient if your technique is not good and good standing technique is much harder than it looks.  Many riders with poor technique weave back and forth across the road when they stand and thrash back and forth, twisting at the hips.  This wastes a lot of energy (which you will wish you had 20 miles further on down the road) and is hard on the lower back possibly leading to back soreness or tightening on long rides.  Experienced riders are likely to disagree with this advice to climb while seated because standing on the climbs is a standard practice among advanced riders.  Having developed the ability to climb efficiently while standing is one of the many skills that separates the advanced rider from the novice.  If you stick with road cycling, you’ll learn to climb in a standing position but when you’re just starting out, I think it’s better to learn to climb efficiently and well while sitting before learning the more difficult skill. 

Keep a loose, relaxed grip on the handlebars.  As you strain up the hill it’s easy to grip the handlebars harder and harder.  White knuckling the handlebars like this can lead to numbness in the hands.  More importantly, the tension in the hands will spread up the arms to the neck, shoulders and chest.  Tightness in the chest will restrict breathing which will reduce oxygen consumption.  Oxygen is essential for both removing waste products and bringing fresh supplies of energy to your working muscles.  Your legs will tire more quickly and you’ll have a harder time finishing the climb if you are not breathing freely.

Keep your momentum as long as you can.  On short or rolling hills keeping momentum is often the difference between an easy climb and a hard one.  If you are approaching a hill from a flat road, build up some speed on the flat so you hit the bottom of the hill moving fast.  Maintain a constant effort when you hit the hill.  As the gradient steals your momentum, downshit to easier gears to keep your momentum going as long as you can.  You will quickly learn to recognize the point on a climb when your forward momentum dies and the climb turns into a pure grunt and you’ll want to prevent that from happening for as long as possible.  If you are riding a series of rolling hills, make use of the preceding downhill to build momentum for the next uphill.  Don’t coast on the downhills.  This will come naturally if you are trying to maintain a constant effort (see Hill Climbing 101) as you will be gearing up and accelerating throughout the downhill.  If you want to put out extra effort, squeeze out every last bit of speed you can on the downhill where it’s relatively easy so you don’t have to work so hard on the following uphill.  As your skills increase you will find that you can fly over hills that once gave you trouble by building the speed you need at the base of the hill and by conserving momentum through the climb by downshifting at just the right moment.

Ride with rhythm.  Many climbs are too long or too steep to be conquered with momentum.  When you’re on one of these, try and find a rhythm that you can ride at comfortably.  Essentially this means finding a cadence that feels right and then using your gears to maintain that cadence as the gradient fluctuates over the course of the climb (see the sections on cadence and maintaining a steady effort in Hill Climbing 101).  The right cadence will feel like a natural, comfortable rhythm.  Shift into a bigger gear when the gradient relaxes and into a smaller gear when the hill steepens to maintain that rhythm.  Don’t worry about what other riders are doing, find your rhythm and stick with it. 

Don’t coast after the crest.  There are going to be times when you crest a hill in agony.  Your legs are screaming for relief, you are in oxygen debt and panting uncontrollably,  and all you want ot do is make it stop.  You’re over the top and now gravity is your friend as it carries you down the other side.  You can coast for a minute; it’s your reward.  Don’t do it.  Keep your legs turning and shift into a higher gear so that you’re getting some resistance from the pedals.  The terrible burning feeling in your legs is produced by the buildup of waste products in the muscles you just overworked.  If you coast and stop using the muscles, those waste products just sit there causing you pain.  If you continue to use the muscles, gently in comparison with what you just did while climbing, the contraction of the muscles will squeeze the waste products out into the bloodstream where they can be carried away.  If you keep pedaling, the pain ends sooner.

Practice on every hill.   It doesn’t matter how long or short the hill is or how large or small the gradient is.  You can always find something to practice and it’s easier to be successful on the small hills than the big ones.  Use every hill as an opportunity to get better.  Success on the small hills today will lead to success on the big ones tomorrow.

Never quit on a hill.  Never.    I don’t really know if this is sound advice or not.  It makes sense and it works for me but anecdotal evidence like this is never worth much.  Here’s the advice anyway.  You’re going to suffer on climbs.  Maybe you went too fast on the early part of the climb and went into the red zone, maybe you blew a shift and killed your momentum, maybe you just don’t have enough left at the end of a long ride to take the climb in stride.  Whatever the cause, you are going to suffer.  The temptation to give up on the climb will be overwhelming.  Don’t do it, fight to the end, pay the price.  Suffer.  A lot of learning to climb is about training the body but some of it is about training the mind.  To be the kind of rider who doesn’t quit, you have to practice not quitting.  If you’re a road rider for any length of time, sooner or later someone is going to challenge you on a climb.  If their skill and fitness levels are so far beyond yours that it is no contest, they’re a jackass who has no business challenging you in the first place.  Ignore them.  However, if the riders are close in skill and fitness it usually comes down to heart and will.  Who will endure the greatest amount of suffering and not break.  If you have refused to quit on every hill in the past, you know that no matter how bad it gets, you’ve been through it before.  You didn’t quit then, so don’t quit now.  Believe me, the first time some guy challenges you on a hill and you break him and drop him in the last 100 meters of the climb it will all have been worth it.

Hill Climbing 101: Pedaling and Shifting

Hills are the bane and the salvation of the road cyclist.  They’re hard, sometimes agonizingly hard, and yet without them road cycling would be unbearably boring.  I’ve had the good fortune to have ridden some of the Laura rounding turn 12 on l'Alpe d'Huezgreat Tour de France climbs in the French Alps like l’Alpe d’Huez and the Col du Galibier.  I’ve also ridden 30 miles of prairie road that was dead flat and straight as an arrow.  If given the choice, I’d ride the climbs every time.  Climbs are the yardsticks by which experienced cyclists measure themselves while new riders often look on them with fear and loathing.

This is one of a pair of posts designed to help new riders climb.  I’ll look at some riding techniques in Hill Climbing 102.  In this post I’ll examine pedaling and shifting.  There are many different approaches to climbing and riders at different stages of development will tackle a climb differently.  A new rider who is desperate to survive to the crest will climb very differently from an experienced racer trying to drop the competition on the steepest part of the climb.  Hill Climbing 101 and 102 are written for the relatively inexperienced cyclist who might benefit from some information about basic climbing techniques.

Cadence.  Cadence refers to how fast your feet go around on the pedals and it lies at the heart of cycling whether on hills or flats.  Most cycling computers measure cadence in revolutions per minute (rpm) although cyclists will often speak of cadences of 90 or 100 and leave out the “rpm”.  There are two basic approaches to cadence:  Spinning and mashing.  Spinning means pedaling in a small (easy) gear at a high cadence while mashing is pedaling in a big (hard) gear at lower cadence.  In very rough terms, spinning will generally build cardiovascular fitness and endurance while mashing will build strength and bulk.  Mashing is also more likely to produce muscle and joint (especially knee) injuries.  As a very general strategy, spinning is usually better than mashing although there are so many different kinds of riders and different kinds of road conditions that there will be many exceptions to this general rule.  The typical recommendation is to spin at cadences of 85 to 105.  This may be a difficult cadence for new riders to maintain but it is good to practice until you can comfortably ride in this range.   When climbing, it is best to spin at a high cadence in a small gear.  Many times you may find yourself climbing in your smallest gear so you can’t shift into an easier gear and spin at a higher cadence.  However, as your fitness improves or the gradient of the hill lessens you can begin to ride in bigger gears.  When this happens, work on achieving a higher cadence on the climbs before you work on climbing in a bigger gear.

Maintaining a steady effort.  If there were one bit of advice that I would hold out as the holy grail of long-distance riding technique, this is it.  The idea is to put forth the same amount of effort consistently throughout the ride.  One way to do this is to maintain a steady cadence.  You adjust for changes in gradient, road conditions, wind, fatigue, etcetera by changing gears and keeping your legs going around at the same rate.  This means that going downhill you gear up into bigger gears and accelerate; going uphill you gear down into smaller gears and decelerate.  Many riders try to maintain a constant speed rather than a constant effort going uphill.  They tend to exhaust themselves on the steeper parts of the hill and then lose momentum on the flatter parts of the hill.  On many hills the gradient will become a bit less steep for the last section before the crest.  The rider who is focused on speed will ramp down their effort as the climb becomes less difficult.  When they back off the effort they often back off too far, lose momentum, slow down and find it difficult to switch from slowing down to speeding up while they’re still climbing.   The rider who is focused on maintaining a constant effort will kick into a higher gear when the gradient eases up and fly over the crest.

Pedaling in a circle.  Once when riding in the Washington DC AidsRide (340 miles in 4 days to raise money to help those suffering from HIV/AIDS) I was riding alongside some inexperienced riders giving them help and encouragement as they climbed a long hill and I suggested they pedal in circle.  As he struggled to keep going, one of riders looked at me like I’d lost my mind and said “Isn’t that what we’re doing?”  Surprisingly, the answer was “no”; his feet were going around in a circle but like most inexperienced cyclists he wasn’t applying force to the pedals all the way around the circle.  As much as you can, try and exert force all the way around the pedaling arc, not just on the downward push.  Push down, pull back at the bottom, lift up and pull through at the top.  This is not as easy as it sounds and it is a skill that takes a long time to master.  However, climbing is difficult enough without trying to do it with only part of your available muscle power.  You’ve got a whole leg and 360 degrees of arc to move it through.  Use the whole thing.  Pedaling in a circle is impossible if your feet are not connected to the pedals.  It’s much harder to do with basket-style toe clips because when you pull back at the bottom of the pedal stroke, you pull your foot off the pedal.  You really need clipless pedals to take full advantage of pedaling in a circle.

Gear shifting.  This is perhaps the most difficult hill-climbing skill to develop.  When there is load on the chain, such as when you’re climbing a hill, downshifting to an easier gear puts more strain on the chain and the shifting mechanism than shifting up to a harder gear.  You’ll often need to downshift to an easier gear during a climb but if you don’t do it soon enough, there may be so much stress on the chain that you can’t make the shift and then you’re stopped dead in a gear that’s too big to get up the hill.  On the other hand, if you downshift too soon, you lose your momentum which can turn an easy climb into a hard one in the blink of an eye.  You can feel this happen if you downshift to an easier gear and suddenly your feet are spinning on the pedals and meeting very little resistance.  It’s all about timing.  The trick is to relax your pedal stroke for a brief instant and shift into the easier gear a split second before you have to so that you can put forth the same effort throughout the climb.  The only way to get good at this is to practice.  There’s nothing like a perfect climb where each shift comes smoothly at precisely the right moment and you feel like you’ve just flown over the hill as if it wasn’t there.

Climbing is hard but learning to climb is worth it.  During the AidsRide I rode up and down that hill I mentioned earlier several times helping riders make it to the top.  The hill was the longest on the entire 340 mile ride and many of the new riders had been dreading it since the ride began.  I began riding with one woman at the bottom of the climb who was very much overweight and out of shape.  Like maybe 100 lbs overweight.  In addition, she was riding a hybid rather than a road bike which was making the climb a good deal more difficult for her.  About a quarter of the way up, she knew she wasn’t going to make it.  I talked to her about the hill climbing techniques discussed here and in Hill Climbing 102 and encouraged her to keep going.  Another 10 feet, just make it another 10 feet.  She was in agony.  Just 10 more feet.  The hill had such a fearsome reputation that a good number of people had stopped to stand along the road and cheer the riders on as they struggled up the climb.  Someone had parked a van with a sound system in the back near the top of the hill and Gloria Gaynor’s disco anthem “I Will Survive”  was booming out.  We’re halfway up and the woman was going so slowly that I don’t know how she remained upright on the bike; I had to keep looping around in small circles next to her in order to move fast enough not to lose my balance.  She knew she wasn’t going to make it but she refused to give up until she absolutely couldn’t give it one more pedal stroke.  Just 10 more feet.  Tears of pain and effort were streaming down her face.  About 30 feet from the top of the hill amidst the music and the cheers of the onlookers she realized she was going to make it, that she was going to succeed at something that just moments before she believed was impossible.  The look that came over her face at that instant was so beautiful and so pure that it made every moment I had suffered building the climbing strength that allowed me to ride with her that day worth it.  It was the kind of thing you never forget.  Hills will do that for you.