System-Optimised™ Design is a different approach to wheel design. The wheels have distinctly different front and rear rims to maximize performance.
Each wheel on a bike plays a different role, and is subject to different forces and airflow. It seems obvious when you think about it, but a wheelset should be thought of as a system, rather than a matching set. Instead of designing a generic rim, that could be used front or rear (as other manufacturers do), we designed a specific rim for the front wheel, and a different rim for the rear wheel.
We found through CFD (Computational Fluid Dynamics) testing that System-Optimised™ wheelsets offered performance gains over their symmetrical counterparts.
The front wheel is more susceptible to crosswind interference. As a result, our new front rims have a lower rim depth than the rear, are more torroidal ('O' shaped cross-section), and wider at their widest point.
The Rear wheel is less effected by cross winds, so it features a deeper rim. This deeper rim also helps to add the strength and stiffness necessary to support the majority of the riders weight and power transfer.
Air flows over the rear wheel differently than it does the front. By including a seat tube in front of the rear wheel in our CFD simulations, we were able to create a more realistic model of airflow. When we optimised the shape of the rear rim for this situation (slightly more 'U' shaped than the front, and narrower at it's maximum width), we were able to reduce drag created by the rear wheel.
As a result, the new System-Optimised™ front and rear rims have uniquly different shapes.
For climbing and sprinting we have developed the EPIC 3.4 featuring a 33mm deep front rim and a 43mm deep rear rim.
Check out this post for a more technical look at the engineering that went into the EPIC 3.4
For fast all-purpose riding we have developed the EPIC 5.6 featuring a 55mm deep front rim and a 65mm deep rear rim.
For triathlon we have developed the EPIC 7.10 featuring a 75mm deep front rim and a 100mm deep rear rim.
These System-Optimised™ rim shapes will allow you to ride faster and farther with less effort.