Tokyowheel: Simulating Carbon Fiber Racing Wheels with SimScale


Founded in 2010, the Japan-based company Tokyowheel is a highly-specialized company that is developing carbon fiber racing wheels for competitive cyclists. Their wheels for road, triathlon, and cyclocross bikes provide performance improvements through decreased aerodynamic drag and lightweight carbon fiber construction.

The Challenge for Tokyowheel

Today, engineering aerodynamic wheels can be done with the use of Computer-Aided Engineering (CAE) as opposed to historical methods of prototyping and wind tunnel testing. While historical methods certainly produced competitive results and moved the industry forward, they were time-consuming and required significant resources. CAE can provide similar results in a lot less time, and with a significantly smaller investment.

Computational Fluid Dynamics (CFD), in particular, is prohibitively expensive with annual software subscriptions costing tens of thousands of dollars. Engineers at Tokyowheel realized that SimScale was a perfect fit for their products. SimScale allowed them to perform fluid flow analyses of strategically different wheel designs in parallel and in a timely and cost-effective manner.

By using SimScale’s cloud-based platform, Tokyowheel’s team was able to run many more simulations, and in turn iterate more design changes. Each design change was quickly implemented in CAD, and immediately tested in the SimScale environment to inform further work and design decisions.


Snappyhexmesh by Tokyowheel

After producing a CAD model of the wheel using a Multiple Reference Frame (MRF) domain, the geometries were uploaded to SimScale for meshing. In essence, a virtual wind tunnel was set up to mimic a real-world cycling environment. The domain contained a moving floor and the wheel geometry. The wheel was then rotated about its axis at an angular velocity that matched the tangential velocity of the floor. The inlet air speed entering the wind tunnel was set to match these conditions.

The simulations include a variety of wind angles (yaw angles) to generate drag values across the entire spectrum of riding conditions a cyclist may encounter. All of these parameters, and their consequent boundary conditions, produced strikingly impressive results.Mesh Tokyowheel project with SimScale

The manual snappyHexMesh was used for meshing, with an added rotating region approximated by the MRF method. Mesh refinements consisted of turbulent boundary layer refinements and surface refinements. A number of challenges were faced along the way – most notably, establishing the boundary conditions and meshing errors. All these challenges were overcome with SimScale tutorials, and personal 1:1 tutoring.


“In the end, the simulations performed excellently! We compared the drag numbers and surface data generated by SimScale to those generated by other CFD packages and found a higher degree of accuracy and detail. We ran around 10 different simulations to generate the most accurate data we could,” says Joel Scott, Production Engineer at Tokyowheel.

Wheel simulation Tokyowheel

The simulations took 30 minutes to run on average, using 16 cores. Ultimately, the engineers at Tokyowheel obtained drag force values on both the axis of travel and the perpendicular axis. The resultant data was crucial for determining the most aerodynamic wheel profile. After testing multiple designs, the engineers were able to converge on the most aerodynamic wheel design.

Wheel simulation with SimScale - TokyowheelTokyowheel - simulation with SimScale

“Tokyowheel’s next steps will be completely iterative as we test more and more rim profiles, at different yaw angles, and compare the data. The results of our CFD simulations direct much of the design and manufacturing process. We will also be comparing our CFD results to wind tunnel data during the later stages of development, in addition to testing the designs with real cyclists on the road. We are confident the improvements that the SimScale CFD simulations have provided will result in a significant benefit to our customers’ cycling performance.” declared Joel Scott.

SimScale is the world's first cloud-based simulation platform, enabling you to perform CFD, FEA, or thermal analyses. Sign up for the 14-day free trial and join the community of 70 000 engineers and designers. No payment data required.