Fulcrum Speed 25 ultralight carbon wheels are focused on going up, up, up

Feathery sub-1,300 g actual weight, a shallow profile, easy tubeless compatibility, and a versatile 21 mm inner width make for wheels built for climbing.

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With so much emphasis on aerodynamic efficiency on the road these days, it might seem a little odd to see a new high-end wheelset from a major brand that’s focused more intently on reducing weight with minimal regard for drag. Yet that’s just what Fulcrum has done with its new Speed 25. There’s little talk of wind tunnels and NACA profiles and that sort of thing, but it’s also missing a whole bunch of grams, too — and it probably feels fantastic to ride uphill.

Light makes right?

The Speed 25 is all about shaving grams, starting with its shallow 26 mm depth (so shouldn’t they be called the Speed 26?) instead of the more common 35-50 mm figures that currently dominate the high-end road wheel market. We don’t have a claimed rim weight handy, but actual weight of a set that recently arrived for testing is a paltry 1,295 g with a Campagnolo-compatible freehub body — just 10 g heavier than claimed.

The U-shaped profile perhaps retains a modicum of aerodynamic efficiency — and if so, Fulcrum isn’t making a big deal of it — but the bigger story is the differential cross-section. Fulcrum is using a symmetrical shape up front, but an asymmetrical one out back with the spoke bed offset slightly to the non-driveside. This is an old (but still effective) trick to help balance out spoke tensions from one side to the other, and Fulcrum claims it also makes for a more responsive-feeling wheel under power. 

Inner width on both rims is a fairly generous 21 mm, and with a 27.6 mm outer width, Fulcrum has optimized the setup for 25-28 mm tires. Those tires can be tubeless or tube-type, and for those opting for the former, there’s no temperamental rim tape required thanks to the solid outer rim wall. 

Whichever way you decide to go on tires, however, it’s disc-brakes only for the Speed 25; there are no plans for a rim-brake version.

Hub shells are made of forged aluminum, and they spin on Fulcrum’s “USB” hybrid ceramic bearings with easily adjustable preload. Out back is a conventional pawl-type ratchet mechanism, but with a 36-tooth ratchet ring for a relatively quick 10° engagement speed. Freehub bodies are offered for Shimano, SRAM XDR, and Campagnolo N3W cassettes. 

The aluminum hubs rotate on Fulcrum’s USB hybrid ceramic bearings.

Connecting everything together are 24 straight-pull bladed stainless steel spokes front and rear with aluminum nipples in a conventional two-cross pattern. Quite interestingly, though, Fulcrum has intentionally engineered the spoke paths so that they don’t actually touch at the crossings, which should eliminate the creaking that can occasionally plague wheels with black-finished spokes. 

Retail price is US$2,526 / £2,000 / €2,190, with some slight variations depending on freehub body selection. Australian pricing is still to be confirmed, but wherever you happen to be, wheels are supposedly available in shops and online now. We’re just waiting for some bits and pieces for our test set, and should have a full review in the coming weeks. 

More information can be found at www.fulcrumwheels.com.

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