The 420 Aero 3’s are stronger than ever for serious riders and racers. They are the best do-it-all wheels on the market, strong enough for racing or training. The new lightweight high–low hub flange is engineered to carry balanced spoke tension on all spokes for increased side-to-side stiffness and strength. The Series 3 spoke system results in consistent spoke tension and shares the load equally for increased wheel durability. The 420 rim is the lightest deep-section clincher rim in the world with technology designed by Bill Shook and an improved braking surface. Low spoke count bladed spokes shave weight, and boost aerodynamics and stiffness. The rim profile and bladed spokes slice the wind to hold your high-end cruising speed. The ride is fast, responsive, and smooth with great accelerating properties, brisk climbing, and speedy descent.
THREE GROUP SPOKE SYSTEM
BALANCE OF SPOKE TENSION
Bill Shook obsessively engineers every wheel system to its optimal “sweet spot”, the balance of spoke tension, hub flange width, spoke angle, and selection of the appropriate materials. After years of research and development, Bill Shook designed the American Classic three-group spoke lacing for our 24-spoke rear wheel systems to build the strongest, stiffest and lightest road rear wheels in our line. We call this advanced system Series 3 for our 420 Aero 3, Magnesium, Road Tubeless, Aluminum Tubular, and Carbon wheels. These good-looking, hand-built three-group spoke wheels are at the forefront of performance, aerodynamics, comfort and durability.
The concept behind this lacing pattern is to create equal spoke tension for the drive and non-drive sides of the rear wheel, a state that cannot be reached in traditionally spoked wheels. Mathematically, this unique balance of spoke tension occurs on 24 spoked rear wheels. To achieve this balance, the rims are drilled in groups of three spoke holes. The spokes are laced to our finely crafted American Classic high-low 24 spoke hub, two on the drive side of the wheel to one on the non-drive side. The result is more spokes on the drive side where the wheel needs to be strongest, and fewer spokes on the non-drive side. Bill Shook calculated the optimal position for the non-drive side hub flange to create the ideal bracing angle of the non-drive side spokes. “The three group spoke design is a better use of materials achieving the balanced use of the spokes with equal spoke tension on both sides of the rear wheel,”says Shook.
The wheels are stiff and light to decisively dive into corners and power out, accelerate repeatedly, climb and descend with ease and hold speed on the flats. There are no broken spokes. No flexy feeling out of the saddle. When winning is your goal, the time-tested three group spoke wheel system delivers.
