How AeroEdge works

Drop in a ride file. The AeroEdge advanced model does the rest.

Your number, in one line

Your number is how well you cut through the air. Smaller is faster.

Engineers call it CdA. A rider sat up on a road bike is around 0.30. A good time-trial position gets near 0.20 or below. At racing speed the air is usually the biggest thing slowing you down, so this is the number most worth knowing.

All we need is a ride file

Any file off your bike computer works: a plain FIT file from a Garmin or Wahoo, or a Notio, GiBLI or AeroSensor file if you ride with a wind sensor. No special kit is needed to start.

The advanced model takes it from there. From that one file it:

• Finds the parts of the ride it can trust: steady stretches, loops, and out-and-backs. You do not have to mark anything.
• Works out the wind. Measured every second if you have a sensor; otherwise worked out from the weather for the exact time and place you rode.
• Holds your tyres and chain to real data, corrected for the day's temperature, so their cost does not leak into your aero number.
• Checks itself. The same ride is worked out more than one way, and against your GPS altitude. When the answers agree, the number is good.
• Reads your corners from the GPS: how hard you cornered, and how much speed you left on the table.

Each run also keeps the weather from the day you rode it, so the number will not drift if you open the ride again next year.

A test day, start to finish

• Make a session for the day, and add a bike if you track your kit.
• Drop each ride into it. The model reads the file straight away.
• Tell us your tyre and your chain so the model can price them.
• Riding indoors? Tick the indoor box and give us the temperature.
• Want a specific stretch? Drag across the ride and it gets its own number. Otherwise the model's auto-detected runs are already there.

Where to test

The model needs a ride that comes back to where it started: a loop, or out and back on the same road. It does not have to be flat; roughly 100 m of climbing over 6 km or less is fine, with each direction holding for at least 90 seconds without braking.

Wind hurts through its gusting, not its strength: a gusty 2 m/s wrecks what a steady 4 m/s would sail through. Set a test venue in your profile and AeroEdge watches the forecast and flags the next calm window for you.

Testing two setups? Ride A, then B, then A again, in the same session, so a real difference cannot be confused with the day drifting underneath you.

Reading your result

The big number at the top is your CdA for this ride. Under it, a line says where the wind came from: measured by your sensor, looked up from the weather, worked out from your ride, or still air. That line matters, because wind is what makes or breaks the number.

Everything else is the model showing its working: the ride drawn from your GPS, the virtual-elevation trace sitting on your real altitude, the power you would need to hold each speed, and your corners. Want all of it? It is behind Open raw data.

On a paid plan you also get the give or take: how far the number could be out, and which input is making it wobble. It is measured from your own ride, not guessed, and a wide one is the ride telling you to test again before you act on it.

If you are on the free plan

You get your number straight away, and it is the same one paying members get; we do not round it off. You also get the ride drawn from your GPS, your cornering, and the power to hold each speed in the air you actually rode in.

Every free result says "Confirm this in advanced analysis.", because a single ride read quickly is a good answer, not a checked one. Paying keeps your rides, unlocks the full workbench, and shows you the give or take.

Comparing two setups

Two numbers that look different can still be nothing but noise. Each setup gets a CV%: how much your own repeat laps disagreed with each other. Under 3% is reliable. And a gap between setups smaller than the day's own scatter is within noise: real on paper, meaningless in practice. Ignore it and test the next thing.

If you have a coach

Link a coach or fitter to your account and they can open and analyse your rides while the link is live. You stay the owner of everything, and you can cut the link whenever you want.

The full method

For the whole method behind the advanced model — the virtual-elevation trace, the cross-checks, the wind sensors we read, and where the give or take comes from — see How the analysis works, which includes a worked example from a real ride. For a proper test protocol in depth, the AeroEdge Academy course covers it end to end.