How Easy It Is to Cheat with Aerodynamic Data: A Concrete Example

How Easy It Is to Cheat with Aerodynamic Data: A Concrete Example

It is incredibly easy to manipulate aerodynamic data to make a product look better than it actually is. We already dived deep into this topic in this blog post. To make things a bit more concrete, we conducted a test in our Tempo! Wind Tunnel to demonstrate exactly how effortless it is to skew the data.

We tested our new Tempo! Road Race Suit against two other configurations - our Tempo! Two Jersey and our Tempo! One Jersey. The goal was to show how we easily could have manipulated the results using the exact tricks we highlighted in our previous post. If you haven't read that one yet, we highly recommend checking it out before reading on, read it here. Let's dive into the test.

 

The Setup: Keeping It Real

To ensure the fairest possible comparison, both the Tempo! Two and Tempo! One jerseys were paired with a set of Tempo! One Bibs. This ensured that the lower body fabric remained identical to the road race suit they were being tested against.

  • Yaw Angle: 4 degrees (a standard angle that represents a realistic weighted average of what a rider faces on the open road).
  • Tested Speeds: 32.4 km/h, 39.6 km/h, 46.8 km/h, and 54 km/h.
  • Why the odd numbers? We measure in meters per second (m/s) in our wind tunnel, so these correspond exactly to 9, 11, 13, and 15 m/s.

We chose these specific speeds to map out a performance curve and illustrate the drag crisis occurring within the fabrics. Additionally, the three products feature distinctly different sleeve structures that behave entirely differently depending on the velocity.

A Note on Wind Speed: Remember to think of wind speed as the effective airspeed hitting you as a rider. For example, if you are riding at 28 km/h into a light headwind of 18 km/h, the air hitting you is traveling at 46 km/h. Conversely, a tailwind significantly reduces your effective airspeed. This is why looking at higher wind speeds makes perfect sense - even if they are higher than what you usually see on your bike computer.

 

Important Caveats: Aero is Personal

Before we look at the results in CdA and watts, a quick disclaimer: the watt savings we mention won’t necessarily translate perfectly to you. Aerodynamics is far more personal than marketing departments like to admit, something we see every day when testing athletes in our wind tunnel.

When selecting fabrics for the kits available on our website, we work hard to choose materials that perform well across the board. We don’t pick a hyper-specific fabric that only works on one specific body type; we test our products on many riders with different builds and sizes to ensure broad, reliable performance.

That being said, the trends and differences we see across rider types generally mirror the examples below. (And as a final note, all suits were tested in a tight, proper fit to avoid skewing the results with mismatched sizing).

 

The Results: Speed by Speed

In almost every scenario, the Tempo! Road Race Suit came out faster than both the Tempo! Two Jersey (designed for lower speeds) and the Tempo! One Jersey (designed for slightly higher speeds). The main differences lie in the completely distinct sleeve textures, body fabrics, and seam placements. The Tempo! Two is a classic zippered jersey, the Tempo! One drops the front zipper for a painted-on fit, and the Road Race Suit is a full skinsuit.

Here is how they performed as the pace picked up:

  • At 32 km/h: All three options are neck-and-neck. While the Road Race Suit is technically faster, the differences are so minimal that the Tempo! Two Jersey, with its significantly lower price point, is an excellent choice here.
  • At 40 km/h: The Road Race Suit begins to pull away, offering a clear advantage, while the two jerseys remain extremely close to each other.
  • At 46.8 km/h: Something interesting happens. The Road Race Suit maintains its solid properties, but it is caught by the Tempo! One Jersey. The rougher texture on the Tempo! One sleeves hits its aerodynamic sweet spot here, managing to close the gap to the skinsuit despite the structural advantage a one-piece suit normally provides. Meanwhile, the Tempo! Two begins to lag behind.
  • At 54 km/h: The Road Race Suit pulls ahead once again, validating its material blend designed to perform across a wide spectrum of speeds. Both the Tempo! One and Two jerseys have passed the point where their sleeve texture is too aggressive, losing control of the turbulent airflow (a concept we explained in our previous blog post).

 

How We Could Have Manipulated the Data

If we wanted to stretch the truth, we could easily spin these results to fit a narrative:

  • The "Just as Good" Spin: We could claim that the Tempo! Two Jersey is so fast it is fully competitive with a premium Road Race Suit. While technically true, it's only true at the lowest tested speed. This highlights why it is absolutely critical for brands to disclose the exact testing speed when presenting aero data.
  • The "9.8 Watt Savings" Headline: We could scream from the rooftops that the Tempo! Road Race Suit saves you 9.8 watts compared to the Tempo! Two Jersey. But if your average riding speed is closer to 32 km/h, quoting savings found at 54 km/h is highly misleading, as you will rarely encounter those conditions.
  • The Strawman Fallacy: We also tested these items against our entry-level C3 Jersey (though we didn't include it in the main charts). Bringing the C3 into the mix makes crafting an impressive marketing campaign incredibly easy. At 46.8 km/h, there is a whopping 20.1-watt difference between the C3 Jersey and the Road Race Suit. At 54 km/h, that gap skyrockets to 30.1 watts.

Boasting that our new Road Race Suit is "over 30 watts faster" in a wind tunnel sounds incredible. But it isn't an honest comparison. We are pitting two products against each other that were built for entirely different audiences and purposes. The Road Race Suit is what you wear when you are hunting for every single marginal gain. The C3 Jersey is the comfortable, relaxed jersey you love wearing when you just want to get out into nature and enjoy the ride.

 

Our Philosophy

When we test daily in our own Tempo! Wind Tunnel, we do so with these exact nuances in mind. That is why you rarely see us publishing absolute watt figures - out of respect for both you and the scientific method we adhere to.

What you can count on is that we test and optimize our gear every single day. We only launch or update products when we find a proven difference. One we have tested so thoroughly that we are absolutely certain it will make you faster on the bike, whether you are a triathlete or a road racer.