What do fish, F1 cars and fast triathletes all have in common? It’s all about the aero. (Technically, with fish it’s actually about the hydrodynamics, but bear with me) Athletes go to a lot of trouble to reduce drag and increase their aerodynamic efficiency. You may think that some go overboard in the quest to be aero, but as you’ll see, the little things add up. Not everyone can afford to spend a fortune on the latest gear, but there are definitely plenty of things you can do to get more aero and watch your times come down.
When it comes to talking aero for triathletes, there’s a lot of stuff out there, both written and on video. The science can get extremely complicated, with talk about rolling resistance, drag coefficients and air density. But I believe there’s a lot to be said for keeping it simple. Instead of getting bogged down in the details, I’m going to strip it back and give you five principles that anyone can apply to lift their performance. They can help you to make more efficient use of your power output and stop you from being such a drag, so to speak!
Principle 1 – Begin with the basics
Having a clear understanding of aero is a crucial first step. Aerodynamics is the study of the properties of moving air and the interaction between the air and solid bodies moving through it. The characteristics of a solid object (or person) regarding the way air flows around it are known as its aerodynamics.
When it comes to triathlon, races are won by the fastest competitor. Speed is a function of power (watts) over time. Push out the greatest amount of power for the longest time and you should be the winner, every time. And in a perfect (airless) world that would be true. But, you need to factor in air resistance, also known as drag. And drag is definitely a drag. Drag reduces your speed, reduces your effective power output and saps your strength.
To give you some idea of the effect of drag, consider the current world cycling records:
- The record for distance covered in one hour on a standard road bike is 49.7km.
- On a time trial bike in the extreme ‘Superman’ position it’s 56.4km
- On a fully-faired recumbent bike it’s 90.6km.
By cutting down the drag they were able to achieve twice the speed of a standard road bike, with the same power output. And reducing drag is all about going aero.
The amount of air resistance you generate depends on a couple of major factors and a couple of minor ones. The major factors are the frontal area you present to the air and the speed at which you ride. The minor factors are the slipperiness of your clothing and the degree of turbulence you generate as you ride through the air. More turbulence equals more air resistance.
Principle 2 – Little things add up
Want to double your speed? In a perfect world, you’d just double your power output. But drag isn’t like that. It works on a factor of 2. Double your speed and you quadruple your air resistance. That means to double your speed takes 8 times the wattage! To increase your speed by 25% means you need to almost double your power output. If you’re interested in doing the maths for yourself, check out this cool interactive website.
You can see how little changes – both increases and decreases – in aerodynamic efficiency can add up fast. Obviously it’s important to maximise your power output, but at the same time the key is getting the most speed out of that power – the most bang for your buck. Small increases in drag are going to suck your power, whilst small decreases will help you go faster on less watts.
There’s no ‘magic bullet’ when it comes to going aero. It’s all about chasing the small gains in aerodynamic efficiency that quickly add up to serious improvements in performance. When it comes to testing what works and what doesn’t, you could pay the big bucks and use a wind tunnel, but using a power meter or even just rolling down a hill from the same point and clocking your speed will give you a pretty good idea. And obviously if your bike legs are faster than before, then you’re doing something right.
There are three basic areas you can tweak to become more aero – clothing, equipment (not just your bike) and your riding position.
Principle 3 – Slippery is good
When it comes to clothing, the key is to reduce turbulence. Quite simply, flappy, loose clothing is going to create more air resistance. I’m interested in this, because one of my sponsors, Scody, have done a lot of research on this and developed the Optimise A.I.R. Triathlon race suit. It’s a move away from the traditional two-piece option and it’s wind-tunnel tested and uses hi-tech fabrics and zoned construction.
The bottom-line on the Optimise A.I.R. Is a 6 watt saving at 50kmh over the old two-piece suit. Over a 90km cycle leg that can shave off about 4:30 if you’re averaging 230 watts, which is a massive time saving. Think about what you’re wearing and what it’s made of – slippery is good!
Principle 4 – Streamline your gear
About 75% of the air resistance is generated by you, but that still leaves another 25% that is caused by your bike and other gear. Analyse that 25% and it comes down to three aspects- surface character (slipperiness again), frontal surface area (the front profile that is pushing through the air) and shape (determines how smooth the flow of air is over your gear). The aim is to choose gear with a slippery surface character, minimal frontal surface area and an aerodynamic shape that creates the least disturbance to the air flow. When it comes to gear, we’re talking bikes, helmets and hydration and nutrition. Here are a few pointers about each one of these:
Bikes – I’m in the lucky position of being sponsored by Giant, so I’ve got access to the latest, state-of-the-art gear. I’ve watched the Giant bikes evolve and become more aero as new research is done and new materials are developed.
Not everyone can access the latest and greatest, so let me say a couple of things about choosing your bike. Firstly, keep things in perspective. You can spend a lot of money on a bike and many manufacturers make big claims about their products. Seek out a cost-effective option from a reputable brand that suits your budget. Do your homework, ask around and beware of just following the latest fad. At the end of the day, remember we’re only talking about 25% of the aero equation. It’s not all about the bike.
Secondly, don’t sacrifice comfort and rideability for the latest hi-tech machine – always pick a bike that suits your build and riding style. All the aerodynamics in the world won’t help you if it doesn’t feel good to ride.
Helmets – same goes for your helmet. Don’t sacrifice comfort for a small improvement in aero. The last thing I want to do is to cook my brain at Kona in the pursuit of a couple of extra minutes! But helmets are a cost-effective way of significantly reducing your drag. Obviously they don’t reduce your frontal area, but they improve the airflow over your head and body, reducing your drag coefficient and your time by up to 4 minutes over IM distance.
There has been a shift in the style of helmets recently from the classic pointed-tail designs to what’s known as the ‘bobtail’ or short tail aero design. I’ve found these comfortable, easy to put on and take off and most importantly the improved through-flow means they don’t overheat.
Hydration and nutrition – nobody is carrying their bottle on the downtube these days – it disturbs the airflow way too much. The other options are horizontally between your aerobars or horizontally behind your seat. Both increase the aero factor compared with the downtube option. There’s been a lot of wind tunnel testing on both these placements. In the final analysis, the best option will actually depend on your body shape and riding position. For some riders, between the aerobars can improve overall aerodynamic efficiency, helping to create better flow over the rider. For others, behind the seat is more streamlined.
The one thing I would say is that the position also has to be practical. There’s no point having your bottle stashed behind you if you can’t easily access it, or worse still if you forget to drink from it. Dehydration is a much more serious problem than a little drag!
When it comes to nutrition, there are new options all the time. Again, easy access is still important. If you’re carrying it on your back, just ensure your shape stays streamlined and the pouch is close-fitting. Increasingly, bike manufacturers are starting to build drink and food holders into the frames themselves to increase the aero.
Principle 5 – Balance your riding position
The basic idea here is to ride in a position that reduces frontal area and which creates a smooth shape that maximises laminar airflow and reduces turbulence. This is where the balance comes in – there’s no point being more aero if your hips are impinged so you can’t maintain the watts or your chest is constricted and you can’t get enough oxygen. It’s also important to consider this in the larger context of the race – you’ve got to be able to run when you get off the bike. It’s a matter of tweaking the variables to find the sweet spot which maximises aero and which is sustainable.
Start with aerobars – they’re designed to decrease your frontal area. To give you some idea – just adding aerobars can reduce the amount of power you need to generate by almost 17%. That’s a huge saving. Adjust them to find a comfortable and sustainable riding position. Call this your baseline position and then begin to experiment, doing some simple comparisons as you drop the bars. To some extent, the width between the bars will depend on your body shape and flexibility.
While you’re tweaking your position, don’t forget to work on your core strength and flexibility. Ease into your new riding position and when you get comfortable and can maintain the watts, experiment again. A couple of things that seem to work well for some athletes – flattening the back and ‘turtling’ the head downward can save you a few minutes. However, holding this position can be more demanding. Again, it’s about experimenting and finding the balance between aero, power and sustainability.
For me, I’ve had to compromise on reducing my frontal area, because if I go too low it compresses my hip angle down and reduces power. To balance that we’ve reduced the length of my cranks to keep my hips a little more open. That’s the right balance for me.
A final word – about fish
Think about fish. In Nature, creatures are designed to conserve energy and fish are a great example of this. Their streamlined shapes and economic use of power are something we can learn from. And it’s a reminder that going aero is not just about the bike. Given that water is more than 800 times denser than air, going ‘hydro’ is also pretty critical. A more hydrodynamic swimming style is going to save you time and energy so you come out of the water faster and fresher. But that’s a topic for another day.
Good luck in your quest for going aero. Don’t be afraid to experiment and find out what works best for you. Drop the drag, cut your times and get the most out of your energy buck. Oh, and don’t forget to shave your legs before the big race. It will save you 23.3 seconds and your partner will appreciate it… seriously!