Faster and More Stable: Turbulent Aero Delivers Speed

Faster and More Stable: Turbulent Aero Delivers Speed

When we introduced Turbulent Aero Technology back in 2022, we had ambitious hopes for its potential impact on Reserve road wheels. Overall, the concept is relatively simple and intuitive: capture real-world wind conditions and then replicate them in the wind tunnel to make faster, more stable wheels. Sounds easy, right? Except for the hard part, it was.

Before we get into that, let’s take a step back and look at wind-tunnel testing prior to the point we starting working on Turbulent Aero. Common practice in a wind tunnel had been to stick a fancy bike part in the tunnel and pummel it with air from the front. We are sure you have seen the nice looking pictures of colored smoke outlining the shape of a tucked-in rider. These tests are all well and good, but certainly not 100% transferable to what you feel when you're riding a bike in the real-world (where wind is coming from all directions at all speeds).

Armed with a hunch that there was more meat on the bone in terms of aerodynamics, it was pretty clear which direction this project was headed. We knew that the key to developing faster and more stable wheels would be understanding the wind conditions that the rider was actually experiencing.

The next step: determining what kind of device we should design and build to collect the data. Not surprisingly, we weren’t the first people that had the idea to capture real-world wind conditions, however the fatal flaw in previous attempts was in attaching data-capture equipment to the bike. In these attempts, the weight and complexity of the equipment interfered with the rider’s ability to actually ride the bike. In a nutshell, it undermined the ability to capture the real-world part of the data.

In the end, we came up with the relatively wild-looking (at least for the California Highway Patrol) data collection array which we mounted to a three-wheeled scooter purchased in Europe and imported to the US. The wind-capture sensors were the easy part in the next step if you can believe it–except the $45K per sensor cost–as they're used commonly in the commercial aviation industry.

The sensors collected a wide variety of information, including air temperature, air pressure, barometric pressure, wind speed and wind direction. The data’s level of sophistication was relatively high. In addition, the amount of data we captured was relatively big, as we logged in excess of 1,500 miles all across the USA and Europe.

One of the more difficult aspects in the process was writing the software to read the data that we would later use to recreate wind conditions in the wind tunnel. We initially looked for open-source code however, it eventually became evident that nothing fit our needs exactly. As it turned out, we had some internal expertise (one of our manufacturing engineers Joe Doty) who basically built an application from the ground up to get us what we needed.

The third step in the process was to use the data we collected to program the wind tunnel in order to replicate the turbulence found in the real world. We used a new-to-the-bicycle industry wind-tunnel created by a Guelph, Canada-based engineering company, RWDI. RWDI is an authority on wind engineering for tall skyscrapers and landmarks. One of the more noteworthy stories about RWDI describes their project to eliminate resonating sound on the Golden Gate Bridge. In that particular case, RWDI captured actual wind conditions on the bridge itself and built an identical scale-shifted model which they used to replicate wind conditions in their tunnel.

We basically did the same thing, but at full scale. We designed multiple shapes and profiles of different rims which we 3D printed to iterate quickly through different designs, proposing, testing and proving/disproving hypotheses prior to opening up tooling on the rims. The goal, of course, was to reduce overall drag, but we also focused heavily on improving stability.

All of the initial work culminated in the creation of Reserve’s first Turbulent Aero wheelset, the 52|63. One of the primary features of the 52|63 are the mixed profiles, a design philosophy we introduced with the 34/37 and 40/44. In general, a taller profile rims allow for lower drag and thus aerodynamic advantage over a shorter profile, so one might think a taller profile always makes sense (to improve efficiency).

We found through testing that crosswinds on a front wheel have a direct effect on steering, so it’s all about finding the balance between low drag and crosswind stability. By making the front wheel profile slightly shorter, wider, and rounder, we're able to lessen the effects of crosswinds at the handlebars, increasing front end stability across all wind conditions.

The rear wheel, on the other hand, has design parameters VERY different to those of the front wheel. For starters, steering input is a non-issue with a rear wheel, and because the rear wheel is partially shielded by the frame and rider, air is channeled over the bike and rider, reducing the effect of that crosswind and completely changing the aerodynamic conditions the wheel needs to perform in.

As a result, the rear wheel is taller and narrower than the front, to reduce overall drag. But a taller rim means more material, so here again the focus is on finding the balance in height that avoids unnecessary weight for the given use case. Lastly, the 63 in this case has an asymmetrical profile, offset away from the cassette, to create a stronger, stiffer and more durable wheel.

The results of Turbulent Aero speak for themselves. Our accomplishments in the Pro Peloton in 2023 with Team Visma-Lease a Bike are solid proof of the project's effectiveness.

That said, our engineers haven’t claimed victory over turbulence yet. There’s a ton more data to collect across different riding conditions, and more (many more) rim profiles to test. They may be headed to a road near you, so if you see the team out there, throw them a thumbs up…or maybe wave vigorously at them–the more turbulence the better!

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