What is the aerodynamic cost of 37.8 liters of packing volume?
There is a moment in bikepacking when aerodynamics suddenly becomes far more tangible than any formula might suggest. It usually arrives late in the afternoon, when the day has already become longer than planned and the campsite is still 30 kilometers away. By then, the body would appreciate a break and the mind is already thinking about a warm meal, while the wind has been blowing for hours from exactly the direction in which the route continues.
The speedometer might show only 18 km/h. The pace feels relaxed, at least by the standards of sporty road cyclists. Yet every kilometer requires a surprising amount of effort. The fully loaded bike feels more sluggish than it did in the morning, the landscape moves past slowly, and at some point it begins to feel as if someone were pulling backward on the luggage.
Days like these are part of traveling by bike. They are part of the adventure because a long headwind section is often followed by the descent, encounter or cake stop that you still remember years later. At the same time, they show very clearly why aerodynamics also matters during relaxed bikepacking. It influences how much energy is left for the final climb.
We therefore wanted to find out what aerodynamic penalty a complete bikepacking setup actually creates. We were particularly interested in a question that is closer to real-world touring than a comparison with a completely empty bike: How efficiently can the luggage that has to come along on a longer journey be carried?
About the author
This article was written by Patrick Zasada. As a passionate gravel rider, bikepacker and long-distance adventurer, he combines practical experience with accessible insights into equipment, planning and aerodynamics. His journeys have taken him to the Portuguese Atlantic coast and the North Cape. Learn more about Patrick on his website.
On a long journey, luggage is part of the bike
The longer the trip and the more varied the conditions, the more obvious it becomes that reducing equipment always requires a realistic framework. On longer journeys, this creates a balance between low weight, adequate safety and the personal comfort you still appreciate after many hours in the saddle. The luggage does not disappear simply because an empty bike would be more aerodynamic. The key task is to place the necessary volume on the bike as efficiently as possible. Anyone who wants to find out which equipment really belongs in the CYCLITE bags for their next journey can use Patrick Zasada's packing list configurator for an individually tailored recommendation.
Practical planning tool
Which equipment really belongs in the bags for your next bike journey? Patrick's packing list configurator creates an individually tailored recommendation.
Why aerodynamics matters even at a relaxed pace
When people think about aerodynamics, many first picture deep-section wheels and road bikes flying along perfectly smooth roads at 45 km/h. A relaxed bike tour with gravel sections, photo stops and a long lunch break seems far removed from that world. Physics, however, still accompanies the bike even when the destination is meant to be reached at an easy pace.
Air resistance depends on speed relative to the air. This is the crucial difference from the number on the speedometer. A rider climbing a steep section at 10 km/h into a 20 km/h headwind experiences an effective airflow of roughly 30 km/h. For the air, riding speed and wind combine, while the landscape still passes by at only 10 km/h.
A touring cyclist can therefore be moving slowly and still experience significant aerodynamic drag. On open plains, along coastlines or in wide mountain valleys, this effect accumulates over many hours. At moderate speeds, the immediate wattage saving is smaller than it is at high speed. At the same time, riders traveling at a relaxed pace spend longer on the road. If a more efficient luggage arrangement makes them slightly faster at the same personal power output, that small difference adds up over many hours and many days of travel. It may hardly be noticeable on one short stage, but over several weeks it can mean more relaxed arrivals, longer breaks and a few extra pieces of cake. In the referenced velodrome comparison, the difference between large rear panniers and a bikepacking setup at around 200 watts added up to roughly twelve minutes per 100 kilometers. That can determine whether there is still time to stay by the lake a little longer or whether the campsite reception is already closed on arrival.
Aerodynamic efficiency on a bike journey therefore means giving away less energy to the wind. The energy saved can be used for greater range, a more comfortable pace or simply fresher legs at the end of the day.
The question behind the test
Three configurations were compared in the outdoor aero test. The gravel bike without bikepacking bags served as the reference. The complete CYCLITE Touring Set with the HANDLE BAR AERO BAG was then tested. In a third series of measurements, the rest of the Touring configuration remained on the bike while the HANDLE BAR AERO BAG was removed.
The total system weight remained identical in all three main tests. Differences caused by bags and luggage were compensated for with additional weight on the rider so that rolling resistance and riding dynamics remained as comparable as possible. Tires, tire pressure, rider position, clothing and other important factors were also kept constant. The test therefore measured the aerodynamic effect of the complete system consisting of rider, bike, bags and luggage.
The measurements took place on a flat test route approximately one kilometer long. Patrick rode the route several times in both directions and kept his power output and position on the aerobars as consistent as possible. AeroTune was used to evaluate power, speed, route profile and environmental data. The software compares the measurements with a physical resistance model and estimates the aerodynamic drag of the complete setup. Riding in both directions helps account for the effect of the wind and compensate for changing conditions as effectively as possible.
The first series of measurements initially confirmed what would be expected from a fully loaded bike. The Touring Set increased aerodynamic drag compared with the empty reference bike. The real surprise was how small this additional drag was relative to the volume being carried and which bag positions performed particularly well within the complete setup.
What the complete Touring Set actually costs
The unloaded reference setup produced a measured CdA of 32.00 dm². With the complete Touring Set and the HANDLE BAR AERO BAG, this value increased to 34.10 dm². This corresponds to an increase of around 6.6 percent. The difference was clearly greater than the calculated measurement uncertainty and therefore shows a distinct effect from the complete luggage system.
The values become more meaningful when these abstract figures are converted into actual power requirements. At 25 km/h, the complete Touring Set required around four watts more than the unloaded bike. At 33 km/h, the difference increased to approximately ten watts, and at 40 km/h it reached about 18 watts. This stronger increase at higher speeds reflects the familiar behavior of aerodynamic drag, which becomes progressively more important as speed rises.
For a modeled route of 100 kilometers at an average power output of 200 watts, the additional riding time was three minutes. Average speed decreased from 30.29 to 29.85 km/h. As expected, the fully loaded bikepacking bike was slower in the model, but the difference remained surprisingly manageable given the large packing volume.
At a typical touring speed of around 25 km/h, the aerodynamic cost of the entire Touring Set is roughly equivalent to the power consumed by a small bike light. These four watts can certainly be felt over a long ride, but they are far removed from the drag that can be created by wide luggage solutions protruding from the sides of the bike.
The reason probably lies in the way the volume is arranged. The bags largely follow the bike's longitudinal axis. The frame bag fills the space inside the main triangle, the saddle bag sits behind the rider and saddle, and the front luggage is placed compactly around the cockpit. This keeps the additional frontal area exposed to the wind comparatively small. The handlebar roll is likely to have the greatest negative effect on the overall system. But when a tent, sleeping mat, sleeping bag or other bulky items have to come along, there are few better alternatives.
Discover the CYCLITE Touring Set
Seven coordinated bags provide a total capacity of 37.8 liters and distribute luggage compactly along the frame, saddle and cockpit.
The first surprise was hidden inside the frame
In addition to the current Touring measurements, an older test protocol was available in which a configuration consisting of frame and top tube bags had been examined. This test produced a CdA of 32.05 dm². The current reference setup without bags measured 32.00 dm². The two values are almost identical.
The measurements were conducted on different days and under different conditions, so the exact values should be treated with caution. Even so, the result is surprising because frame and top tube bags provide a useful amount of storage while their measured aerodynamic effect differs very little from the reference.
A frame bag sits within the bike's existing silhouette. Viewed from the front, it mainly fills an area between the top tube, down tube and seat tube that is already influenced by the frame, bottles and the rider's legs. A narrow top tube bag also follows the shape of the bike closely and adds very little extra frontal area.
In practice, there are therefore strong reasons to use these positions early when planning a setup. Tools, electronics, food and heavier equipment can be stored centrally, helping the bike remain stable while keeping the additional exposed area small. On a long journey, this creates especially valuable storage that can almost seem to disappear into the bike from an aerodynamic perspective.
Discover central storage
The FRAME BAG LARGE / 02 and TOP TUBE BAG LARGE / 02 keep luggage close to the bike's silhouette.
The most exciting moment happened at the handlebars
After testing the complete Touring Set, the same configuration was tested without the HANDLE BAR AERO BAG. The remainder of the setup stayed on the bike and the missing weight was compensated for again. On paper, the bike now had one bag fewer and might intuitively have been expected to move through the air more efficiently.
The measurements told a different story.
With the HANDLE BAR AERO BAG, the Touring setup had a CdA of 34.10 dm². After the bag was removed, the value increased to 34.70 dm². At 25 km/h, the configuration without the AERO BAG required around two watts more, at 33 km/h the difference was approximately three watts, and at 40 km/h it reached five watts. In the model calculation over 100 kilometers, the complete setup with the bag was roughly one and a half minutes faster than the same configuration without it.
The difference of 0.60 dm² is close to the combined uncertainty range of the outdoor test. The exact wattage should therefore be understood as a positive tendency within this specific setup. At the same time, the result was consistent across the speeds considered and matched an existing assumption about the front section.
The HANDLE BAR AERO BAG probably creates a more favorable transition between the cockpit, handlebar roll and rider. An exposed handlebar roll generates turbulence around its edges and transitions. The additional bag may smooth this area and guide the airflow around the entire package in a more controlled way. Its own surface area may be offset by the more efficient shape of the complete front setup.
The test did not make the airflow itself visible, so this explanation remains a plausible interpretation. What was measured was the result of the complete system, and within that system the configuration with the HANDLE BAR AERO BAG required five watts less at 40 km/h than the identical Touring setup without the bag.
This revealed one of the most interesting findings of the entire investigation: With bike bags, the effect on the overall shape matters more than the number of bags mounted on the bike.
Discover the HANDLE BAR AERO BAG / 02
The 4.9-liter handlebar bag can be used on its own or together with the HANDLE BAR ROLL BAG / 02. In the outdoor test, the complete front setup with the AERO BAG showed a positive aerodynamic tendency.
The realistic comparison begins with other luggage systems
An unloaded gravel bike provides a clean technical reference, but it represents a multi-week bike journey only in theory. On a two-month trip, clothing, sleeping equipment, tools, food and weather protection all need somewhere to go. Once this volume is fixed, the way it is carried becomes the real decision.
Large rear panniers provide plenty of space and are easy to pack. Their wide arrangement on the left and right of the rear wheel, however, significantly increases the bike's frontal area. In crosswinds, they also sit well outside the silhouette of the rider and frame, creating additional drag.
The test report cites comparison values of approximately 14 additional watts at 25 km/h and 59 watts at 40 km/h for two large rear panniers with a similar total capacity. Under the respective model conditions, the complete CYCLITE Touring Set required around four and 18 additional watts. Because these values come from different tests, they indicate an order of magnitude rather than a direct comparison under identical conditions.
A cited velodrome test points in a similar direction. Different luggage configurations were ridden at the same weight and around 200 watts. The average speed was 30.17 km/h with bikepacking bags and 28.20 km/h with two large rear panniers. The pannier configuration was therefore around 6.5 percent slower and required approximately twelve additional minutes over the projected 100 kilometers. Each of the tested panniers held roughly 21 liters, so this result should primarily be treated as a guide for large bags that extend far from the sides of the bike.
The difference comes from the shape of the complete bike. Volume positioned inside the frame or lengthwise behind the rider and handlebars largely remains within a narrow silhouette. Bags mounted at the sides make the bike significantly wider and are exposed to greater loads in headwinds and angled airflow.
A compact arrangement offers further advantages when traveling on narrow paths, in dense traffic or across windy plateaus. The bike is easier to move through tight spaces or along trails. Aerodynamics and handling follow the same basic idea: The luggage should remain as close to the bike as possible.
Four watts can change a long day
Four watts at 25 km/h may sound small at first. On a relaxed tour, they disappear among climbs, gravel, traffic lights and photo stops. Over many hours, however, they still add up to a real amount of energy that the rider has to produce.
Anyone riding for eight hours a day feels the combined effect of headwinds, rough surfaces, small climbs, fatigue and a bike that continually demands a little more power. That is why reducing unnecessary resistance in several areas is worthwhile. Each individual improvement remains modest, but together they determine how the bike feels after 120 kilometers.
The same principle applies to riding time. A more aerodynamic setup may save only seconds or a few minutes over a short distance. On long days, the gap grows because the small difference remains effective over every kilometer. A slower rider is also on the road for longer and exposed to the wind for more time. At the same personal power output, even a small difference in speed can grow into a noticeable time difference over several hours.
The effect becomes even clearer in a headwind. At a riding speed of 20 km/h with a frontal wind of 20 km/h, the air hits the bike and rider at an effective speed of roughly 40 km/h. Under these conditions, a wide luggage solution is subjected to aerodynamic forces similar to those experienced during very fast riding.
On bike journeys, aerodynamics therefore mainly creates a calmer, more efficient system. The bike maintains its pace with slightly less effort, long flat sections feel smoother and a windy afternoon consumes fewer reserves. Perhaps the accommodation is reached a few minutes earlier. Perhaps there is enough strength left on the final climb to enjoy the view. And perhaps the bakery is still open on arrival in the next town.
Efficiency leaves more room for the adventure itself
Patrick describes his first major bike journey to Portugal as a month that felt like an entire year. The route crossed the Alps, brought countless encounters and finally reached the Atlantic. The value of a journey like this cannot be explained in watts. It comes from the feeling of continuing into an unfamiliar landscape under your own power.
Even so, the setup determines how much energy remains for exactly these experiences. A poorly distributed luggage system can make the bike feel sluggish for weeks, constantly pull at the handlebars in crosswinds and require additional effort on every exposed road. A compact arrangement carries the same equipment closer to the bike's natural shape and, in the best case, makes it noticeably less present while riding.
In the present test, the complete CYCLITE Touring Set increased aerodynamic drag by around 6.6 percent compared with the unloaded gravel bike. At a typical touring speed of 25 km/h, this corresponded to approximately four watts. Considering the large packing volume, this penalty remained moderate, particularly when compared with conventional panniers that extend far beyond the bike's silhouette.
In an older protocol, frame and top tube bags produced almost the same CdA as the current reference bike without bags and may therefore be among the most aerodynamically efficient positions for touring luggage. Within the complete Touring setup, the HANDLE BAR AERO BAG reduced the measured drag and required around five watts less at 40 km/h than the same setup without the bag. The exact size of this effect requires further testing, but its direction offers an interesting indication of how important the shape of the entire front section can be.
This also resolves the question from the beginning. A fully loaded bikepacking bike requires additional energy, but the size of this disadvantage depends greatly on how the necessary volume is distributed on the bike. The Touring Set keeps a large proportion of the luggage within a narrow, elongated silhouette and therefore carries the equipment much more efficiently than wide solutions mounted at the sides.
On a real bike journey, this advantage rarely appears as a spectacular moment on the speedometer. Sometimes the extra half a kilometer per hour is noticeable, and sometimes it barely registers. Even so, it quietly accompanies every kilometer. The rider arrives with a sleeping bag, rain jacket, tools and everything else needed along the way. Ideally, there is still enough time left to truly enjoy a warm meal.
Technical test report
Complete technical aerodynamics test report
The report contains the complete measurement protocols, test conditions, uncertainties and a description of the outdoor testing method.
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