Fulcrum has gone wider and deeper with its newest Speed 42 and 57 wheelsets, offering what the Italian brand claims are the best hoops in terms of “aerodynamics, rolling resistance, lightness and handling, without compromising safety”.
According to Fulcrum, the Speed 42 and 57 are 2mm deeper than their predecessors, while the inner rim width has been increased from 19mm to 23mm. Moreover, the section of the rim where the spokes enter has also been widened to a radius of 9.5mm, resulting in both improved aerodynamics and stability.
“The new wider rims, paired with 28mm tires, provide a level of performance without compromises, with optimum aerodynamic penetration, rolling resistance and comfort,” says Fulcrum. “The average aerodynamic advantage, measured in the wind tunnel with wind generating from the front, has been increased by 10% compared to a rim with an inner rim width of 19mm.”
“Despite the higher profile, handling has been improved considerably,” Fulcrum adds. “We carried out a specific research project to define a formula that would take into account the energy dissipated by the wheel during changes in direction and the flexural deformation based on roll and inclination. The data measured confirmed that the new Speed wheels have seen an improvement of up to 17% compared to the previous generation.”
Elsewhere, the new wheelsets use a new composite mix of FF100 high-modulus unidirectional fibers, which Fulcrum says results in less weight, but improved compliance.
“Through numerous experiments we have reached the perfect mix of fibers, which along with their correct layup and an extremely precise control of the resin, allows us to create a product that works in the correct elasticity field, guaranteeing hors catégory performance specifications and a superior ride feel,” explains Fulcrum.
Additionally, the Speed 42 and 57 also feature molded spoke holes and Fulcrum’s Directional Rim-Spoke Coupling system, wherein plastic supports are incorporated into carbon between the rim and the spoke nipples in order to increase stiffness and durability. Also, the hubs have been redesigned as well, which now have smaller flanges and hub bodies compared to the previous generation, while the bearings still rely on a cup and cone design, along with Fulcrum’s Ceramic Ultra Smooth Bearings system. Further, the freehub now features a 36-tooth ratchet system that’s available with a Campagnolo N3W, Shimano HG, or Sram XDR body.
“The size of the flanges has been reduced by 40% and the central body by 10% compared to the previous generation, giving the wheel greater resistance with lower aerodynamic drag, without compromising torsional stiffness,” says Fulcrum.
Lastly, newly designed spokes were also developed for Fulcrum’s Two-to-One system.
“Our system doubles the spokes in the areas subject to greater mechanical stresses to prevent the dispersion of energy and contrast the torsional force. The front wheel has 16 spokes on the disc side and eight on the non-disc side. The rear wheel is built the opposite way, the idea being that the higher number of spokes on the drive side can handle the forces of the transmission. This specific construction, along with the perfect tensioning of the spokes, provides the wheels with the torsional stiffness required to ensure the maximum transfer of power,” says Fulcrum. Considering the flexural deformation and the torsional deformation based on the translation, rolling and inclination energies, the new Speed achieves a 10% improvement compared to the previous generation,” Fulcrum points out.
Also, if you’re interested in knowing more about the Speed 42 and 57’s handling properties, Fulcrum offers the following white paper data:
“The physical quantities used to define these indexes are mass (kg), rotational inertia (kg/m2), flexural stiffness (N/mm) and torsional stiffness (Nm/rad), whilst the joule (J) is used to measure the energy dissipated. Handling considers the energy dissipated by the wheel during a change in direction. The less energy is dissipated the higher the performance index. The handling assessment considers the flexural deformation based on rolling and inclination. Reactivity considers the energy dissipated by the wheel during a sprint, therefore the flexural deformation and torsional deformation are based on the translation, rolling and inclination energies. In other words, the rider’s pedal stroke deforms the wheel and the energy absorbed for the deformation is not transferred to the ground to move forward. The greater the amount of energy absorbed the lower the reactivity and therefore the performance of the wheel. For example, a wheel can’t be very reactive and very comfortable at the same time. A higher flexural stiffness results in greater reactivity, whilst low stiffness is synonymous with comfort. It’s therefore not necessarily true to say that a very stiff wheel is the best wheel: the aim is to find the right balance to offer a wheel package suited to the requirements of every single rider.”
The Fulcrum Speed 42 wheelset sells for £1,999.99, while Speed 57, or Speed 42/57 combo will be available starting next month for the same price.
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