Fulcrum has announced new Fulcrum Speed 42 and 57 wheels, claiming the wider and deeper rims handle better than the models they replace.
The new Speed disc-brake only wheels replace the previous 40mm and 55mm sizes. The 42mm-deep wheelset weighs a claimed 1,410g, while the 57mm version is said to weigh 1,495g.
They use much of the same technology as the shallower Fulcrum Speed 25 wheelset.
The Fulcrum Speed 42 is available to buy now for £1,999/$2,692/€2,265. The Fulcrum Speed 57 is coming in June and will cost the same, positioning both wheelsets at the top of the brand's price range.
Undrilled, hooked rims
When riding into a headwind, the brand says the new 23mm internal rim width is 10 per cent more aerodynamic than the previous 19mm rim width.
Fulcrum claims the Speed 42 and 57 wheels handle up to 17 per cent better than before, despite being deeper.
The brand says it calculated this figure using a formula that takes into account how much energy the wheel dissipates when changing direction and flexing.
The brand claims the hole-less rim channel enables any tubeless road bike tyre to be fitted without rim tape, while maintaining even stiffness and increasing strength.
The polished internal finish of the rim is said to facilitate the mounting and seating of the tyre.
Because the rim is hooked, it also works with clincher road bike tyres.
However, on the Speed wheels a 700x28mm tyre set up tubeless optimises rolling resistance, comfort and aerodynamics, according to Fulcrum.
The nipple holes are formed in the wheel mould rather than by drilling through the rim. The latter approach weakens the structure, says the Italian brand.
The Fulcrum Speed 42 and 57 wheels are made from a new composite mix of FF100 high-modulus unidirectional fibres. The brand says this “perfect mix of fibres” improves on the ride quality of the outgoing wheels.
Fulcrum says its Directional Rim-Spoke Coupling system sinks a plastic support between the nipples and rim. This is claimed to improve stiffness and durability by spreading stress of the nipples more evenly, while also reducing the risk of corrosion.
More efficient spokes
Fulcrum has laced 24 aerodynamic and straight-pull spokes to the Speed 42 and 57 wheels in its Two-to-One system.
This doubles the number of spokes in the area under greater mechanical stress in order to minimise energy dispersion and counteract torsional force, according to the brand.
As a result, the front wheel has 16 spokes on the brake side and eight on the other. The rear wheel has 16 spokes on the driveside and eight spokes on the non-driveside.
Fulcrum claims this spoke-lacing method has made power transfer 10 per cent more efficient than on the previous Speed wheels.
More aero hubs
The brand says the redesigned hubs hold a lighter and more precise freewheel mechanism than before.
Fulcrum says the flanges are 40 per cent smaller and the central body has reduced in size by 10 per cent. This is claimed to lower aerodynamic drag, while maintaining stiffness.
The ceramic cup and cone bearings in the Speed 42 and 57 provide “unparalleled levels of smoothness”, according to Fulcrum.
The freewheel ratchet system has increased in size to 36 teeth, which translates into a 10-degree engagement angle. This is comparable to other performance road bike wheelsets.
The wheelsets are available with Campagnolo, SRAM and Shimano freehub bodies.
