In the relatively short history of carbon wheels, Reynolds has been at the forefront of technology, innovation and product leadership. Nothing symbolizes that commitment better than does the Reynolds Composites Studio. The idea behind Reynolds Composites Studio was to create a design-engineering environment where innovation is a mandate and performance is a mantra. It’s the first stage in continuous process that allows us to control carbon wheel technology all the way from concept to customer.
Reynolds established the Composites Studio as a focused environment for exploring technologies, techniques, materials and processes that have the potential to transform the cycling experience for riders at every level. We’ve committed the resources and company support to a team of experienced, visionary engineers, then challenged them to throw convention to the wind in the search of the ultimate carbon wheel performance. It’s where we developed the revolutionary designs in the RZR 46 and 92 wheels. And it’s where we’re working with exciting new materials, such as boron and carbon nano tubes, that have the promise to deliver strength and stiffness at a fraction of the weight of standard carbon. RCS supplies design and engineering expertise for both Reynolds, as well as a select group of manufacturing partners.
The RCS team is headed by the legendary composites engineer Paul Lew. As Director of Technology and Innovation, Paul is responsible for many of the designs, molds, tooling, production and techniques that are at the heart of the Reynolds carbon wheel product line. Considered to be among the first to apply unidirectional carbon technology to bicycle rims, many of Paul’s innovations are now considered state-of-the-art in wheel design.
Paul has authored a number of technical white papers that cover a variety of subjects related to carbon fiber wheel technology. We’ve included links to those six white papers below.
In early February 2011, Reynolds engineers, led by Paul Lew, carried a quiver of wheels – their own as well as competitors – into the state-of-the-art A2 wind tunnel facility. The data from those tests indicates that Reynolds wheels offer the best performance. The best performing wheel does not mean only the lowest aerodynamic drag value, but the wheel inertia must be considered. Because all competition does not occur at 30 MPH, and because climbing and acceleration are factors in bicycle racing, wheel inertia becomes an important factor in wheel performance. The combination of aerodynamic performance and low inertia results in an overall performance value.
The A2 Wind Tunnel testing session yielded some surprising and very gratifying results for Reynolds Cycling. We invite you to view the summary document from that test, below.
A2 Wind Tunnel testing validated that the Reynolds RZR 92 is faster than the market leader's 81mm F/R and F/R Disc combinations.
Carbon, Aerodynamics, and Aero Watts
Arguments surrounding weight and aerodynamics have long been central to the conversation of cycling technology. But in recent years, public attention to the merits of strength, light weight and aero properties have risen to the level of obsession within the sport. One key reason for the buzz has to do with the revolution in performance brought about by the application of carbon fiber as material of choice for just about every modern bike component (with the exception of tires and bar tape.) Unlike such "traditional" materials as steel, aluminum and titanium, carbon presents an unprecedented opportunity for designers to deliver light weight and strength and aerodynamics. Until recently, carbon's weight and strength have grabbed most of the attention, simply because they are relatively easy to measure and quantify. During the past few years, however, as designers and engineers have ventured further outside the box to develop radical, new approaches to managing drag, aerodynamics has begun to dominate the conversation - just as it has the bicycle showroom floor.
And while measuring drag coefficients is not as easy as measuring weight and strength, the availability of more and more wind tunnel facilities, along with the technical expertise to operate them, means it is now nearly as convenient to attach a numeric value to the benefits of improved aerodynamics. The defining value is known as aero watts, which simply refers to the amount of watts saved as a result of aerodynamic efficiency. This is the story of how Reynolds' top aero wheels fared in a recent wind tunnel test program.
A2 Wind Tunnel Testing
Mooresville, North Carolina. It's safe to say this quiet suburb of Charlotte is making a massive contribution to aerodynamic science, thanks to a group of talented engineers, led by Gary Eaker and Gary Romberg. Eaker is the founder of A2 Wind Tunnel, and a lifelong aerodynamic engineer with a pedigree that includes the General Motors Aerodynamic Laboratories. Romberg has worked with Boeing, NASA and Daimler-Chrysler.
The A2 Wind Tunnel routinely tests the aerodynamic properties of everything from spacecraft to NASCAR racecars to bobsleds and world record-holding land rockets. One important test area includes bicycles, bike components and bike riders. In fact, A2 Wind Tunnel has become the "go-to" aero testing resource in the United States for such cycling companies as Trek, Specialized, HED, Zipp, and now Reynolds. While certainly not the first or only wind tunnel in the United States, A2 is fast gaining respect as a facility dedicated as much to profitable business as it is to good science. Unlike other facilities traditionally connected to a University's school of engineering, A2 caters to organizations and individuals who want to be sure their products, components and techniques come as close as possible to aerodynamic perfection.
In early February 2011, Reynolds engineers, led by Director of Innovation and Technology, Paul Lew, carried a quiver of wheels - their own as well as competitors - into the state-of-the-art A2 wind tunnel facility. The purpose of aerodynamic testing of a bicycle wheel is to determine its drag value, or to determine the amount of drag reduction it contributes to the bicycle system. This adds up to efficiency: an optimization of the bicycle system to reduce the amount of effort required by the rider to move it forward.
Specifically, Lew and his team were looking to test four parameters of performance:
1. Swirl-Lip Generator (Reynolds' proprietary technology designed to smooth turbulence and pressure drag on select rims.)
2. RZR 92 (92mm version of Reynolds RZR wheel line)
3. Wheel only v. bicycle system
4. Tire width effect
Interpreting a Drag Table
In the methodology, wheel or bicycle set-up was tested twice for consistency, and to ensure anomalous data was discovered and deleted or corrected. Two separate runs (data points) were collected for every wheel or bicycle set-up tested, then averaged for primary value. In each of the charts shown, the top value (yellow) is the averaged value. The values in the two rows below the top value are the values representing the two data points (two separate runs). Normalized data allows for variations in barometric pressure, temperature and humidity to be calibrated to an N.A.C.A standard day, which is 29.92 inches of mercury, and 60 degrees F. Data error is +/-0.5 watts; so if watts are within a value to "1" for example 29 v. 28 watts, the statistical error effectively makes the results identical. [For a complete discussion of yaw and other aerodynamic concepts, please refer to the RZR Technical Series, 1-6]
As contextual information for typical road wheels v. aerodynamic/deep section wheels, the average road wheel (25-30mm rim depth) requires 50+/- watts to sustain 30 mph. The average deep section wheel (40-60mm rim depth) requires about 25+/- watts to maintain 30 mph. For reference, 13.175 watts in power reduction translates to 30 seconds of time savings over a 40k distance, at a velocity of 30 mile per hour.
A2 WIND TUNNEL RESULTS: RIDING THE REYNOLDS RZR SAVES YOU ENERGY & TIME.
Wind Tunnel testing validated that the Reynolds RZR 92 is faster than the market leader's 81mm F/R and F/R Disc combinations.
Your energy (aero watts) savings by riding Reynolds RZR 92:
- 20 watts v. leading 81mm F/R
- 10 watts v. leading 81mm F/R Disc
Other Key Wind Tunnel Data RZR92 Points:
- Reynolds RZR92 rear is faster than a disc wheel
- Reynolds RZR92 is the first wheel that's beaten the leading 81mm in wind tunnel testing.
- Reynolds RZR92 F/R set is not only faster (by 20 watts), but also 400+ grams lighter than the leading 81mm F/R set.
Other Reynolds Wheels vs. the industry's best selling 58mm wheel
- The Reynolds Sixty Six is aerodynamically more efficient, thus faster than its popular competitor
- RZR46 is much more aero and faster than the most popular competitor, + 1lb. lighter
Other Proven Technologies
The RZR 92 wheel performed over a broad range of wind angles, with a larger sweet spot (13.25 degrees) than the leading 81mm competitor (12.5 degrees). The minimum drag of both wheels was equal (within statistical error +/-0.5 watts), however the cumulative drag of the RZR 92 was lower than the cumulative drag of the leading 81mm competitor.
- The Wind Tunnel Testing demonstrated that the Reynolds patented Swirl Lip Generator helps to reduce drag.
This means that over a 40K course, the time savings from riding the RZR92 F/R vs. the leading competitor's 81mm wheels is 5.7 seconds in favor of Reynolds RZR 92.
Swirl-Lip Generator (SLG): Significant drag reduction was achieved as a benefit of the SLG in the Forty-Six and the Sixty-Six models as compared to the Assault and Strike models. The SLG had the effect of reducing the drag of the 46 mm rim depth by approximately 20% at 10 deg yaw. There was a subtle reduction at 0 deg yaw.
Forty-Six 40K time savings = 12.5 seconds
A2 WIND TUNNEL RESULTS: TESTING TRIATHLON BICYCLE WITH ATHLETE
The triathlon bike validates wheel testing by more closely simulating wheel performance in the real world conditions. Wheels do not race without a bicycle and an athlete to power the bike. The interaction of the wheels with the bicycle and the athlete are a critical data point. Wheels must perform well as individual wheels, but more importantly, they must perform when mounted to a bicycle with a cyclist on board. The RZR 92 proved to be a superior wheel when tested as an individual wheel. When mounted on a bicycle, the RZR 92 was validated as the fastest wheel set in the world.
Aerodynamic Testing Summary
The purpose of aerodynamic testing of a bicycle wheel is to determine its drag value, or to determine the amount of drag reduction it contributes to the bicycle system. A complete bicycle system, which is composed of a cyclist and a bicycle, is a complex combination of structural and mechanical components designed to function in an efficient, reliable manner. Characterization of efficiency can be described as, optimization of the bicycle system to reduce the amount of effort required by the rider to move it forward. Many components of the bicycle system can be defined scientifically. One such component is the wheel.
Typical aerodynamic wheel testing protocol has been based upon relative comparison of drag data of individual wheels using identical fixtures and tires for every wheel in an attempt to maintain consistency of variables. There are many reasons this type of test protocol will yield results of little to no value. Testing a wheel in a fixture independent of the bicycle system is similar to expecting to achieve valid structural bicycle frame data independent of a load. No engineer would ever construct a frame and claim that it has been structurally validated without applying a load simulating the dynamic load of a cyclist riding the bicycle. Why then test a wheel independent of factors that interact with it and ultimately define its performance? When was the last time a bicycle wheel raced without a frame or a rider?
Reynolds wheels are designed to work as the lowest drag, lowest mass, and lowest inertia wheels for the best real-world performance, not to perform as an individual wheel.
Complete system testing is the best predictor of real-world performance. Individual wheel testing is not a valid test method for predicting real-world performance.
The test data indicates that Reynolds wheels offer the best performance. The best performing wheel does not mean only the lowest aerodynamic drag value, but the wheel inertia must be considered. Because all competition does not occur at 30 MPH, and because climbing and acceleration are factors in bicycle racing, wheel inertia becomes an important factor in wheel performance. The combination of aerodynamic performance and low inertia results in an overall performance value.
> Download a copy of the RZR92 Executive Summary