■ Handling and Stability Experiment to Pursue Lightweight & High-rigidity Wheels/CHAPTER-2
In handling and stability experiments performed by RAYS on real runs of lightweight and high-rigidity wheels, values are measured via “normal running” while keeping all conditions other than the wheels identical. Even though this is not a time competition, RAYS WHEEL usually shorten the lap times because of the improved road surface tracking ability thanks to the wheel's reduced weight, among other reasons. In addition, this excellent tracking ability also augments the organoleptic performance—in other words, the ease of running and satisfying feelings such as "smooth acceleration/deceleration" and "easy to turn." Though it is difficult to digitize and quantify human sensations, this time we attempted such an analysis.
The Advantages of Lightness Visible from a Microscopic Perspective
The graph shows part of the data; it is an enlargement of a moment of less than 0.5 seconds. Above is the strut stroke amount, while below is the trend in acceleration (G) applied at that time. The lightweight wheels shown in red have fewer strut strokes and smooth waveforms, which is clearly evidence of efficient operation, but also note the lower G input graph in which the waveform's "Peak” is offset slightly. This indicates that "excess" inertia force has come out on a heavyweight wheel to which the inertia force works stronger and compels the suspension to move vainly, in contrast to lightweight wheels in which the undercarriage responds quickly to driving and road surface conditions. Even the individual momentary offsets are small, and this is continuously multiplied during driving without interruption, generating a perceptible difference in driving stability and driving feel/organoleptic performance. This is not possible without high wheel rigidity that realizes an agile response.
"Dynamic Weight," the True Form of Wheel Weight
As the graph shows, the unsprung part always moves fast and finely. As G is applied to a moving object, the weight increases due to inertia. To put it simply, when the weight difference of the wheel is 3 kg, if 2G is applied, a dynamic weight difference of 6 kg (theoretical) will be generated, and if 3G is applied, 9 kg. This difference increases as the tire/wheel becomes larger and heavier. It has long been said that reducing the weight of the unsprung part directly improves running performance. For example, suspension arms and the like are upgraded from iron to aluminum as the car's grade increases. Although some are of the opinion that "a weight difference of several kilograms per wheel does not have much affect," the weight of a wheel located on the extreme end of the unsprung part must have some influence—which is clearly shown by the experiment results.
Maximizing Advantages and Minimizing Disadvantages
The handling and stability experiment compared wheels of the same size. However, the observed difference becomes more prominent every inch the wheel increases. Nevertheless, people thinking about customization basically desire to inch-up. Gripping ability increases in tandem with tire size, and larger tires look better and impress more. A customization that minimizes disadvantages while maximizing advantages is to upgrade to a lightweight and high-rigidity wheel—RAYS WHEEL. RAYS WHEEL
Choose from a wide lineup with wheels that fit all kinds of cars.
■ Engrave "Inscription" of RAYS WHEEL/AMT
Functional performance is not the only thing that boosts organoleptic performance. RAYS contends that one important way to increase organoleptic performance is to maximize the user’s pride and pleasure in being an owner by enhancing the merchantability of aluminum wheels as well as the brand's value by, for example, excellent design, finish work, highly original ideas, and elaborate detailing. Patent No. 6153437, Advanced Machining Technology (AMT)—this RAYS original machining technology carves out an "inscription" suitable for a premium wheel
See them with your own eyes at your nearest RAYS No.1 SHOP
Patented Advanced Machining Technology (AMT) is a technology for cutting that reproduces delicate designs like the brand logo even on three-dimensional curved surfaces. To establish this technique, we at RAYS designed and developed everything from the machine tools to the cutting edge. The brand logos and credit titles that were previously expressed with stickers and molds such as the forging, casting, and so forth are engraved with a beautiful plasticity, and a style that blends into a single piece of modeling has already been adopted for a few wheels on the market as the new symbol of RAYS. Please visit a RAYS No.1 SHOP near you to see the delicate detail that changes its expression and radiance depending on the viewing angle and how it is illuminated.RAYS No.1 SHOP
■ High-performance and cutting-edge camber stiffness analysis
Ever rising engine power and tire performance pose great stress on wheels. Rays sought to achieve both lightness and stiffness, which is basically the strength to reduce flexure and distortion. The analysis technology we have perfected through development of racing wheels is employed for making lighter and more rigid wheels. Stiffness analysis is now employed for making every kind of Rays wheels to provide light and stiff wheels that lead the world without compromising the very basic of safety.
Camber stiffness according to the latest theory of stiffness analysis
High-performance cars keep on evolving. Today, racing machines appear on public roads. Consequently, some wheels require designs that mobilize theories of racing wheels. Rays paid particular attention to camber stiffness for keeping a constant area of a tire contact patch by minimizing the deformation during the cornering. Wheels experience enormous force and inevitable deformation during the cornering. In order to win a race, the latest three-dimensional analysis for designing wheels that are less prone to deformation is a must. The involved theory provides a sure way to enhance lap time.
In the world of racing, each wheel has a specified displacement for the inner rim and outer rim. The displacement must be minimized as much as possible in every kind of environment. Wheels that are less prone to deformation can maintain a constant contact patch of the tire, which translates into better lap time and stable posture of the car. The latter further leads to excellent ride quality. For these reasons, camber stiffness will no doubt become an essential feature of road wheels.
Stiffness analysis technology underpinned by years of buildup
Actually, some earlier ideas provided ground for improving camber stiffness. Stiffness was enhanced initially by depending on the feeling of professional drivers. Later, computers were employed to quantify measurements, and thereby combine analog analyses with digital ones. Further advancement in technological innovation made it possible to conduct simulation analyses. A new technology was introduced to make forecasts based on data from the past, which further accelerated the pace of wheel development. Diminishing boundary between racing wheels and road wheels brought about another benefit of a smaller time lag for introducing the latest technology.
Camber stiffness is an important parameter. Still, heavy wheels are meaningless no matter how stiff they are. In order to further boost the performance of road wheels, Rays wasted no time to combine simulation analysis with forging that employ originally-designed molds for making safer, lighter, and stronger wheels. VOLK RACING TE37 Saga is the latest product that embodies our theory of camber stiffness, which we boast as the leading road wheel that the world can over dream of. The camber stiffness can even support the power and drive of a racing machine. Leading technologies are no longer reserved for racing wheels.
■ History of RAYS in pursuit of ever lighter wheels
Lighter wheels dramatically change the movement of cars. The latest research found that it makes clear differences in driving stability, including greater cornering speed and reduced steering angle. Rays has led the world by developing and providing lighter wheels for numerous users long before such research began. Most of all, VOLK RACING TE37 released about 20 years ago is now a household name in light wheels beloved in the world still today for its regular specification upgrades.
Expanding the potential of light wheels
It all started with the advent of green vehicles. Various efforts have been made to improve their fuel efficiency, including the pursuit of lighter bodies and adoption of hybrid systems. How can wheels help toward this end? In 2011, Rays played a maverick role in the industry to launch an industry-science joint project with the Osaka Institute of Technology to test acceleration performance and fuel efficiency gained by lighter wheels. Later, Rays researched the aerodynamic impact of wheels through wind-tunnel tests at Mie University. The tests bore fruits as our new theory has been applied not only to commercially available wheels, but also to racing wheels used at the World Endurance Championship (WEC).
■ Driving stability tests in quest of truth about lighter and stiffer wheels (ongoing)
No doubt, lighter wheels boost the motion performance of cars. In the past, the impact and involved mechanism were studied based on feedback mainly from professional drivers. Later, computers were employed for conducting more precise analyses. Rays went even further to start a driving stability tests in partnership with other entities. Moreover, verification experiments are carried out with foreign car manufacturers to deepen our understanding of the way lighter and forged wheels influence the driving stability of cars.
The experimental results exceeded expectations!
Data analysis demonstrated the improved driving stability achieved by lighter and stiffer forged wheels by Rays compared to common cast wheels.
Damper load is reduced by replacing wheels with lighter ones, which in turn smoothens the damper stroke. Moreover, the uncomfortable up-thrust is mitigated by reducing shock to the car body. Swift confinement of tire vibration after riding over uneven road surface leads to excellent ride quality.
The figure suggests that lighter and stiffer forged wheels combined with smooth operation of the damper achieves an even increase of the cornering speed from the low-speed range through the medium- to the high-speed range. Moreover, steering became smoother thanks to more direct steering feel. The operation angle was reduced almost by 10 degrees during the apex at a medium speed.
The smooth movement of the damper exerts a positive effect also at the corner exit at a middle speed. The acceleration pedal could be pressed deeper by roughly 10%, increasing the speed of the corner exit. Shocks to the car body and resulting upthrust during cornering were reduced, which not only greatly enhanced stability, but also ride quality.
Replacement of wheels with lighter forged ones will surely boost your ride with increased cornering speed and smoother steering. The ride quality, stability, and other feelings by drivers improved more than expected as upthrust G-force was reduced.
So, are lighter wheels simply better? For instance, is there no difference between a forged wheel and cast wheel when they weigh the same? Rays squarely addresses these questions to solve them one by one.
Forged wheels compared to wheels with the same weight manufactured by other methods proved to offer greater advantages. Materials used for forged wheels are superior than those used for cast wheels in terms of endurance, toughness, hardness, and overall characteristics. The advantages also stem from difference in the surface density stiffness. Further demonstration will be carried out with various cases to deepen our understanding of how lighter and stiffer wheels influence the driving stability.