Like previous SES wheel models the geometry of the SES 7.8 rims is asymmetric from front to back. The front wheel is 71mm deep and 29mm wide while the back wheel is 80mm deep and 27.5mm wide. ENVE’s emphasis on in-frame aero development argues that developing wheels in isolation from the frame doesn’t answer the whole aero equation.
According to aerodynamicist Simon Smart, “Wheels only work in a bicycle frame. To test and develop wheels in isolation from the rest of the system does not answer the right question. The question we are answering is; how do you make the entire system more efficient?” He continues, “When developing a front rim shape we are looking for the best compromise between steering stability and drag reduction from the relatively clean on coming flow. In contrast, the rear wheel is seeing more turbulent flow, a larger frame interaction and we do not need to consider steering stability. It therefore stands to reason that a more efficient solution can be achieved by developing unique front and rear rim shapes.’’
The way that ENVE has made the interaction between wheels and frame more efficient is apparent in the subtleties of the SES 7.8’s rim shapes. The new wheelset not only features dissimilar rim depths and widths from front to back, but also dissimilar sidewall curvatures. The changes to the sidewall curvature enable a better dynamic response to any directional changes in the flow field. This leads to a wheel that has better acceleration, less gust sensitivity and is ultimately faster and less fatiguing from point A to B.
“The SES 7.8 is an amazing wheel, depending on your bike and tire setup, it is as fast or faster than the SES 8.9 but with stability and handling characteristics that rival our shallower SES 6.7,” stated Director of Marketing Jake Pantone.
The next generation SES rim shapes take into consideration the fact that 25mm tires are now the norm for most road cyclists whereas 21-23mm tires were standard during ENVE’s first generation SES development. Also, frame manufacturers have opened up the tolerances on the modern road and triathlon frame which gives wheel manufacturers like ENVE more latitude when considering rim shapes. “The aero segment of the industry has evolved from 3 years ago. People are running larger tires, and frame manufacturers are designing frames with more clearance. These changes have allowed us to optimize the latest generation of SES wheel for 25mm tires and the flow fields of the modern aero frame,” stated VP of R&D Scott Nielson.
The SES 7.8 will begin shipping in November 2015.
Located in Ogden, Utah, ENVE Composites is a manufacturer of handmade carbon fiber bicycle rims and components. Partnering with the prominent frame builders of our time and the world’s best athletes, ENVE combines the best composite technologies with real world athlete feedback to provide our customers with the ultimate in performance, durability, and quality. ENVE designs and manufactures 100% of their rims in their Ogden, Utah, USA facility.