1. Computational Fluid Dynamics (CFD)

Development begins digitally.

We use Computational Fluid Dynamics (CFD) simulations to analyse airflow around simplified wheel, tyre, and bike models. These simulations allow rapid iteration, helping us understand how changes to rim shape, width, and tyre interaction influence drag before physical prototypes exist.

CFD can be run in two ways:

Wheel-only simulations to isolate rim performance

Wheel-in-bike simulations to understand system interaction

This stage allows thousands of design variations to be tested efficiently, guiding which concepts move into physical testing. Promising concepts are then 3D printed in sections, glued togetherto create a full rim, them carefully built as aerodynamically representative prototype wheels that we can wind tunnel test.

2. Wheel-Only Wind Tunnel Testing 

Once designs are validated digitally, we move to controlled physical testing with 3D printed prototypes. Wheel-only wind tunnel testing isolates aerodynamic performance without external variables. The wheel is rotated by a roller under the floor to simulate a riding speed, laminar air is then blown or sucked over the wheel at the same speed from a variety of yaw angles, the force of the air hitting the wheel is measured and used to calculate aerodynamic translational drag. To ensure accuracy the same tyre has to be used for all testing. This allows precise measurement of drag differences between rim profiles, spoke layouts, and tyre combinations. 

For this phase, we partner with: 

• GST Windkanal (Germany) 
• Silverstone Sports Engineering Wind Tunnel (UK) 

Testing individual wheels helps confirm CFD findings and refine small aerodynamic gains that compound into meaningful real-world speed.

3. Wheel + Bike Wind Tunnel Testing 

A wheel never operates alone. The bike frame significantly alters airflow, especially around the fork, downtube, and rear triangle. 

Testing the complete bike and wheel system reveals aerodynamic interactions that isolated testing cannot capture. At this stage we evaluate how airflow transitions between components and how wheel shapes behave within real frame environments. 

This helps ensure performance gains translate beyond laboratory conditions. 

4. Wind Tunnel Testing with a Pedaling Rider 

Adding a rider changes everything. 

Pedaling legs, moving feet, and body position introduce significant turbulence in the airflow containting the rear wheel. Testing with a pedaling rider allows us to understand how the wheel system performance under realistic riding conditions. This stage shows why front and rear wheels perform differently aerodynamically and informs our system-based design philosophy, where each wheel is optimised for its specific aerodynamic environment. Our engineering team tested X front and rear wheel combinations to identify the point where rear wheel aerodynamic gains diminish relative to system weight targets.

5. Real-World Sensor-Based Testing 

Wind tunnels provide control. The road provides truth. 

Our final validation happens outdoors using sensor-based aerodynamic testing with a full rider and bike system. Testing typically takes place on outdoor velodromes, controlled road courses, or runways to minimise environmental variables while maintaining real riding conditions. Outdoor testing is the gold standard of wheel aerodynamic testing, as it is the only way to measure translational energy loss and total rotational drag, all other testing is only telling part of the story and can only be used to estimate performance. For outdoor aero testing, we partner with Dr. Barney Garrood (PhD) at AeroSensor™ (UK). 

This stage captures factors impossible to replicate indoors: 

• Translational Energy Loss  
• Rotational drag  
• Natural wind variability 
• Rider movement and fatigue 
• Surface interaction 
• Real speed fluctuations 

This stage ensures performance gains measured in testing translate into real-world speed for riders. 

Key definitions:  

• Translational Energy Loss: Drag caused by air moving over an object, or from moving an object through the air 
• Rotational Energy Loss: Rider power is used to rotate the wheel through the air, in the case of the spokes and nipples they are traveling at 2x bike speed at the top of the wheels rotation, interacting with air in each rotation. This is what we call rotational energy loss.

A System Built from Every Stage 

No single test defines performance. True aerodynamic development comes from combining digital simulation, controlled laboratory testing, and real-world validation. 

Each method informs the next: 

• CFD accelerates learning 
• Wind tunnels validate precision gains 
• Rider testing reveals real airflow behaviour 
• Outdoor testing confirms real performance 

The third generation Limitless Speed Project is the result of this complete process; engineered not just to test fast, but to ride fast. For a deeper technical breakdown of our methodology and results, explore the full development white paper.