How to get faster on a bike without training more

Why air is the biggest lever

The power you spend on air grows with the cube of speed; the power you spend on rolling grows in a straight line. So the faster you ride, the more of your effort goes into air.

The changes that measured biggest

Each figure below comes from a wind-tunnel or velodrome test, as collected by CYCLINGABOUT. The tests used different riders, speeds and methods, so don't add them up. Read them as sizes, not promises.

• Position. Hands on the grips was 6.2% slower than hands near the stem with flatter arms, at 26 km/h (Specialized wind tunnel). Raising the bars 20 mm added 5% wind resistance, at 32 km/h (Bicycle Quarterly).
• Clothing. Baggy clothing was 5% slower than fitted, at 30 km/h (Specialized). A loose rain jacket added 8% wind resistance (Bicycle Quarterly).
• Luggage. A full set of panniers was 7.9% slower than bikepacking bags, at about 30 km/h (CYCLINGABOUT velodrome). Fork bottles plus a bar pack were 2.1% slower than a bare bike, at 25 km/h (Francis Cade wind tunnel).
• Where the bag sits. A bag hidden in the wake behind your body can add nothing, or even cut drag slightly (Torsten Frank, 107 field runs). Bags that stick out past your knees and shoulders are the ones that cost.

Position or bike weight: which matters more?

On the flat, position, by about ten to one. Using the same model as Table 1 at 25 km/h, making yourself 5% smaller saves about 3.3 W. Taking 1 kg off the bike saves about 0.3 W. Weight comes back on climbs, where you are slow and lifting it, and air matters less.

What 5% is worth

At 25 km/h on the same power, a 5% smaller frontal area is worth about 3.6 minutes per 100 km in that model. Over a multi-day race, that is real time for no extra watts.

The catch: a single photo measurement carries about ±3% error, and a comparison of two about ±4.2%. A 2% change won't show up in one photo. Re-shoot each setup and look for a difference bigger than the noise. How to measure it →

Citations

• Denham, A. "The Fascinating Aerodynamics of Bikepacking and Bicycle Touring." CYCLINGABOUT, 2020. Source for the position, clothing and luggage figures in section 02, with the original tests linked. cyclingabout.com
• Torsten Frank, field aero-test of bikepacking bag setups. 28 tests / 107 runs measuring CdA, with error margins reported. torstenfrank.wordpress.com (in German)