Fulcrum Goes Form and Function – Speed 42 and 57 Wheelsets

Between Sea Otter and the start of the Giro d’Italia, we are seeing a lot of new products being released. Fulcrum is getting in on the excitement with the release of their new Speed 42 and Speed 57 wheelsets.

The new wheelsets are an update on the previous Speed 40 and Speed 55. The new models aim to be lighter, more aerodynamic, and decrease rolling resistance, without giving up handling or safety.

The new models went through over 4,000 hours of testing in the labs, wind tunnel, and real-world riding. Seven versions of the rim, in multiple configurations, were tested to find what Fulcrum believes is the perfect balance of performance, reliability and safety.

Deep Dive Into Testing

Fulcrum worked to quantify specific and objective parameters to measure “ride feel”. Fulcrum’s R&D group tested a wide range of wheels with riders of all shapes and sizes in different riding conditions to create Handling and Reactivity Indexes. They looked at mass (kg), rotational inertia (kg/m2), flexural stiffness (N/mm), and torsional stiffness (Nm/rad), along with the joule (J) to measure the energy dissipated.

This data helps to understand the Handling Index, or how much energy is dissipated by the wheel when you change directions. The less energy lost, the higher the performance index. To make sure they are looking at energy lost from the wheel, they factored our rolling resistance outside of the wheel and changes from the level of the surface.

For the Reactivity Index, Fulcrum looked at the amount of energy lost at high output from flexing and torsion. When you pedal, the wheel absorbs some energy when it flexes, which is not transferred to the tire to propel you forward. The less energy that is absorbed, the higher performance of the wheel.

By looking at this data, Fulcrum wasn’t looking for the highest-performing wheel in these categories, but how they work together and how they it affects the rider. You wouldn’t want a wheel that is absolutely stiff, because it would not be comfortable, yet you wouldn’t want a wheel that has low stiffness as it would not perform well.

The New Wheelsets

The new rims are not only taller, wider, and lighter, but the new shape is also more aerodynamic. Each rim increases by 2mm from 40 to 42mm and 55 to 57mm. The shape of the rim has also been widened to a more blunt 9.5mm radius to create a 29.3mm external width for better aerodynamics. Inner width has increased from 19mm to 23mm to better handle the wider 28mm tires that are popular, with room to spare if you wanted to go even wider. In front on wind testing, Fulcrum found a 10% increase with a 28mm tire versus a 19mm internal width rim.

And while the height of the rm has changed, Fulcrum for significant testing to ensure it would still be compliant enough to positively affect rolling resistance. If a wheel is too stiff, it will bounce off of irregularities in the surface. With a little bit of compliance built-in, the wheel can soak up some of these imperfections, and allow the tire to roll more efficiently. Compared to the previous Speed wheels, Fulcrum found an 18% improvement in rolling resistance.

On the inside, the rim bed has only one hole for the valve. Fulcrum uses its MOMAG process, which uses a magnet to move the nipples through the rim and guides them into place in each spoke hole. The solid rim bed makes for a stronger wheel, along with tubeless compatibility without a rim strip. They finish the rim bed with their C-LUX finish to provide an extremely smooth finish to make mounting tires even easier. Because of the hooked rim design, the new Speed 42 and Speed 57 are compatible to run with or without a tube. Externally, they use their DIMF (Direct Inmold Matt Finish), which nicely shows the layup with a classy matt finish. Graphics are pretty lowkey, though they do highlight a lot of the technology that goes into the wheel.

The rims are made using a new composite mix of FF100 high-modulus unidirectional fibers. Through numerous tests, Fulcrum feels it is the perfect blend when laid up correctly and the right amount of resin is used. This production process helps to give the performance, comfort, and durability that they are looking for while keeping weights down. The Speed 42mm comes in at a claimed 1,410g, while the Speed 57 is claimed at 1,495, impressive for wheels this size.

Inside the rim, Fulcrum uses its patented DRSC (Directional Rim-Spoke Coupling) system, which uses a plastic support to help distribute the stress on the rim in a wider area and avoid galvanic corrosion.

Each wheel is built radial laced with 24 spokes, 16 on the side with the highest mechanical forces, and 8 on the other. In the front, you have more spokes on the brake side, while it is the drive side on the back. This helps to prevent the loss of energy mentioned above, while also helping fight any flex.

The size of the hub has been reduced by 40% at the flanges, and 10% at the body, allowing it to stay stiff and improving aerodynamics. Inside, they use a cup and cone design with loose Ceramic Ultra Smooth Bearings (USB). The Aircraft grade aluminum axle does not allow for adaptors, making this a 12mm TA-only wheelset. You lose flexibility depending on your bike, 12mm is the common standard for road, and it does make for a very simple and solid interface. And while the hub body has decreased in size, the freehub body has actually grown, allowing for a 36-tooth mechanism. It can be set up for Campagnolo N3W, Shimano/SRAM, or XDR freehub bodies.

The new wheelsets will be available as a pair, or a 42/57 combo for those looking for the benefits of a deeper aero wheel in back, and a shallower front wheel that is easier to handle in the wind. Regardless of size, the variation in price comes from the freehub, though it is only a few dollars.

• 2.265,00 € (HG11), 2.264,00 € (XDR), 2.265,00 € (N3W)
• 2.692,00 $ (HG11), 2.703,00 $ (XDR), 2.698,00 $ (N3W)
• 1.999,99 £ (HG11), 1.999,99 £ (XDR), 1.999,99 £ (N3W)

All options will be available in June.

www.fulcrumwheels.com