Updated: Jun 7, 2022
Air resistance or aerodynamic drag is a major factor that affects speed and performance. The faster a rider is going, the more air resistance they must overcome. It's no wonder then that the performance cycling industry has become a leader in pushing the envelope for aerodynamic drag reduction technologies. Aerodynamics is one of the most important aspects of cycling. It is what makes it possible to ride a bicycle at high speeds and helps to make cycling more efficient. When cyclists are riding in a group, aerodynamics also plays a role in helping them to draft off of each other and go faster.
These are track bikes with full disc rims but it is about the most efficient yet UCI legal that a cyclist can reach.
The Impact of Aerodynamic Drag on a Cyclist
Aerodynamic drag is a fluid resistance force that acts on an object as it moves through the air. The effect of aerodynamic drag on the human body is to slow the body down. Aerodynamic drag is caused by a combination of two things - air pressure drag and direct friction. There are plenty of articles that delve deeper into the math and science behind aerodynamics in cycling such as this one from Bicycling.com. The focal point of this article is how cyclists are directly impacted by these forces.
This is what the article is not covering, fluid dynamics.
The formula is simple - the more aerodynamic drag, the more work a cyclist needs to do to propel both themselves and their bikes forward which equates to using more watts to move at the same speed as someone that is more aerodynamically optimized. It follows then, that when drag is reduced, more of the power generated by the cyclist can be directly translated into speed instead of countering air resistance. The need to reduce drag gave birth to the aero position, and subsequently highly-tuned positions set by professional bike fitters.
The aero position is a riding stance that drops the cyclist's center of gravity, bringing their body closer to the ground and decreasing the overall profile presented to the oncoming air. This reduced drag profile results in more efficient use of the rider's power output, allowing them to ride faster for any given effort.
While there are many different interpretations of the perfect aero position, each share certain key characteristics. The rider's chest should be low and compact, the elbows should be close to the body, and the legs should be partially straightened to allow for a more powerful pedal stroke. This position is uncomfortable for many riders, and many time trialists train to hold this position for a long period of time but the increased speed and efficiency more than make up for it.
Straightened back, head forward, arms extended, this is a typical TT position.
Aerodynamic drag can have a significant impact on a cyclist's performance, accounting for up to 90% of the total resistance faced while riding. This resistance increases with higher speeds, making it more difficult to pedal and resulting in a decrease in average speed. Cyclists can reduce the impact of aerodynamic drag by using equipment such as aerodynamic handlebars and helmets.
Bike Improvements That Reduce Aerodynamic Drag
Part of the joy of watching bike races is in following the innovative technologies that teams and racers are using to reduce drag and improve performance. In just the last few years, we've seen some amazing developments. Many cyclists are looking for ways to reduce aerodynamic drag while riding. Although some of the traditional methods, such as tucking in your clothing and using aero bars, can be effective, there are other bike improvements that can be made to help you go even faster. Some of these include choosing the right frame material, adding disc wheels, and using aero helmets. With careful planning and execution, you can make significant reductions in your aerodynamic drag and see a noticeable difference in your cycling performance.
Aero Frame Design
One of the most obvious places that cyclists are looking to reduce drag is with their frame design. In the past, many frames were designed with weight reduction as the primary focus. But, with advances in materials and construction techniques, it's now possible to have a lighter frame that's also more aerodynamic.
Aerodynamic road bike frame designs are becoming increasingly popular as cyclists look for ways to improve their performance. These frames are designed to reduce drag and help the rider go faster. Many top manufacturers are now offering aerodynamic road bike frames, and there is a wide range of prices and designs available. Manufacturers and bike designers now employ tear-drop-shaped tubes instead of the traditional round ones. These new tube shapes help to reduce both air pressure drag and friction drag.
An older track bike frame that a lot of modern aero broad bikes are adopting benefits from.
The difference in air resistance between a standard road bike and an aero road bike at 30mph is around 25%. This means that for the same amount of power, an aero road bike will be 5-6mph faster by reducing the watts required to push the same speed. In racing terms where the difference can be a fraction of a second, this can mean the difference between winning and losing.
Deep Section Wheels
Deep-section wheels are those with a rim depth of at least 30mm, often up to around 65mm. These wheels are more aerodynamic than traditional wheels because they create less drag. Drag is the force that opposes the forward motion of an object moving through a fluid (in this case, air). Therefore, less drag means that deep section wheels can help a cyclist go faster.
The modern peloton features a lot of deep-section wheels, such as the second cyclist in this image.
Wheels are one of the first significant upgrades most cyclists make on their bikes. Often, the default wheels that come with a new bike are made more for durability than performance. This is especially true for entry-level or budget bikes, many of which still use older technologies.
One of the biggest trends in wheel design over the last several years has been the move to deeper section rims. It is not uncommon to see race wheels with rim depths of 40mm or more. The deeper the rim, the more aerodynamic performance it provides.
While many road cyclists still prefer to ride in the drops, an increasing number are making use of aero bars. These handlebar extensions allow riders to assume a much more aerodynamic position on the bike without compromising comfort or control.
Aero bars on a road bike are not authorized for most road races but are a decent solution for the lack of a TT bike or practicing a TT position. Note how the cyclist is more upright than those with a dialed-in position typically set by a bike fitter.
However, it's important to point out that aero bars are actually banned by UCI in events other than Time Trials for many reasons, one being that it is believed to cause crashes in the peloton. Aero bars on road bikes are more commonly seen in the triathlon side of cycling.
Road Cycling Tires
One of the simplest and most effective ways to reduce aerodynamic drag is to use slick road tires as opposed to knobby tires. These tires have less texture and are designed for use on smooth pavement. They are faster than traditional road tires but offer much less grip in wet or cornering conditions.
There have been a lot of innovations in modern road cycling tires as manufacturers are looking to replace tubular tires with tires designed to used tubeless and fitted on a hookless rim along with adding a little texture to otherwise slick tires.
The debate around using wider or skinny tires for road cycling is one that has been going on for many years. There are pros and cons to both as many manufacturers are putting out road tires wider than 28mm, and it really depends on the rider's preference. Some say that wider tires provide more comfort and stability, while others say that skinny tires are lighter and faster. Ultimately, it comes down to what the rider feels most comfortable with.
Wearable Aerodynamic Gear
While the frame, wheels, and tires of a bike play a huge role in aerodynamic drag, the cyclist also presents a high aerodynamic factor. Wearable aerodynamic gear is designed to minimize drag and improve a cyclist’s aerodynamics. This type of gear is usually made from lycra or another form-fitting material and often includes a tight-fitting helmet, gloves, shoes, and clothing. By reducing drag, cyclists are able to ride faster and with less effort. Optimizing aerodynamic efficiency means that t is important to make sure that the gear worn is also as aerodynamic as possible.
A representation of a wind tunnel, one of the common tests for aero cycling gear all the way from road frames to socks.
There are now a number of companies that specialize in making cycling clothing with an eye toward aerodynamics. These garments are often made from special fabrics that help to smooth the airflow over the body and reduce drag.
Aero helmets are perhaps one of the more controversial aero technologies as more companies are creating helmets to increase aerodynamic efficiency without the iconic teardrop TT helmet shape. These helmets are designed to be as aerodynamic as possible and, as such, often sacrifice ventilation in favor of reducing drag. In some world tour races, cyclists often switch between helmets with more or less ventilation throughout the course.
Some riders love them for the performance benefits they offer while others find them too hot and uncomfortable to use. Ultimately, it's up to each individual rider to decide whether an aero helmet is right for them.
Another piece of gear that's often used in an effort to reduce aerodynamic drag is the skinsuit. A skinsuit is a form-fitting garment that is often used by road cyclists. Skinsuits can be made from a variety of materials, but they are typically made from Lycra or spandex. Skinsuits are designed to provide aerodynamic benefits and improve comfort and performance. These one-piece garments are form-fitting, some companies even make clothing contoured for the individual rider's measurements, which smooths out the rider's contours to help reduce drag. They are, however, often uncomfortable and impractical for everyday use.
Socks and Shoe Covers
Aerodynamic socks and shoe covers are an important part of road cycling. They help to improve your aerodynamic profile by smoothing out the airflow around your feet. This can help you to ride faster and with less effort. Shoe covers also protect the feet from the elements and can help to keep them warm in cold weather. Wearing socks and shoe covers that are smooth and close-fitting can also help to reduce aerodynamic drag. These items help to smooth out the airflow over the feet and lower legs, reducing drag in the process. One way that socks can be aerodynamically shaped for road cycling is by tapering them at the ankle to provide a slim fit, and by using materials that are proven to improve airflow around the foot. These design features help to reduce drag and improve performance.
A good pair of cycling socks can provide more aerodynamic advantages than a bare leg, while a pair typically used for training may provide decent wicking but more drag.
Bicyclists and manufacturers test for aerodynamics in a number of ways. In the wind tunnel, engineers can measure how much drag a bicycle and rider create at different speeds and yaw angles. They also use computational fluid dynamics to model airflow around bicycles and riders in order to understand and optimize aerodynamic performance. Additionally, on-road testing is conducted to gather data about real-world conditions. This can be done with power meters and other sensors that measure variables like speed, wattage, and heart rate.
The Future of Aerodynamics in Cycling
As the sport of cycling becomes more and more competitive, even the smallest advantage can be the difference between winning and losing or setting a new PR. For that reason, we can expect to see more and more companies redesigning their products to be more aerodynamic. Aerodynamics plays a critical role in the sport of cycling, with riders often looking for any advantage they can get to help them ride faster. In recent years, there have been some major advancements in aerodynamic technology, and it is only going to continue to improve. The future of aerodynamics in cycling is very exciting, and it will no doubt lead to even faster times and more competitive races.
For example, there's a current wave of cycling computers and sensors coming out that are designed to be as aerodynamic as possible. These devices are often very small and sleek, making them ideal for use in time trials and other fast-paced events. As for cycling kits, designers are constantly tinkering with different fabrics and materials that can help riders go faster. We can expect to see more and more riders using aero kits in the future as they look for any advantage they can get. It is also worth noting that the UCI is constantly changing the rules surrounding what is and is not allowed in terms of aerodynamic gear. One example is checking the length of socks in road races. As such, it's important to stay up-to-date on the latest rules and regulations before using any new gear in competition.
While admittedly, most of these improvements can only provide marginal aerodynamic enhancements, it is important to understand that the sum of marginal gains in both bike improvements and the cyclist's kit can result in a significant reduction in the total aerodynamic drag. Aerodynamics play a crucial role in road bicycling, as they significantly affect a rider's speed. Even small improvements to a bike or cyclist's kit can result in a significant reduction in drag, making a big difference in race outcomes. In other words, every little bit helps. When it comes to racing, or even just riding fast, aerodynamics matter.