Fulcrum has released low-profile Speed 25 wheels, designed for climbing performance, with a claimed weight of just 1,285g.
“They are the ideal wheels for cyclists looking to post their best times uphill, but also for ultra-cyclists who have to deal with adverse weather conditions and want a stable and reliable wheel even in strong gusts of wind,” says Fulcrum.
The Speed 25s, for use with disc brakes, have a 26mm-deep rim profile. The front one is symmetrical while the rear is asymmetrical, the idea being to allow the use of “better dish angles” to achieve great lateral stiffness, according to Fulcrum.
Light weight is the Speed 25’s key characteristic, says Fulcrum, hence the relatively shallow rim profile.
The rim features Fulcrum’s matt finish straight from the mould – which it calls DIMF, or Direct Inmold Matt Finish – the lack of a subsequent treatment helping to keep the weight down.
“This has been made possible by using specific resins that also protect the rim,” says Fulcrum.
The inner rim width is 21mm – common on performance-type road bike wheels these days – while the bridge is non-drilled (meaning there are no holes in the bottom of the air chamber when you have your tyres fitted). This allows you to fit tubeless tyres without the need for rim tape.
Fulcrum uses its MoMag (Mounting Magnet) technique where the spoke nipples are pushed into the rim via the valve hole and guided magnetically to where they’re needed.
“The minimal design of the hub makes a considerable contribution to the low weight,” says Fulcrum. “Its weight has been reduced and its internal and external sections have been optimised so that it is as aerodynamic as possible, as well as reliable, strong and able to withstand considerable torsional stresses.”
The hubs feature Fulcrum/Campagnolo’s USB (Ultra Smooth Bearings) ceramic bearings. Fulcrum claims that these offer 50% less rolling resistance than standard bearings.
The double-butted spokes – 24 front and rear – are designed to be aerodynamically efficient and they don’t touch where they cross.
“There are various advantages to this approach: constant long-term durability, resistance and stiffness, without any of the creaks that can develop when spokes rub,” says Fulcrum.
The wheels are held in place by CNCed through axles (12 x 100mm at the front, 12 x 142mm at the rear).
Although Fulcrum makes several mentions of aerodynamics concerning the Speed 25s, it hasn’t made any specific claims in that area, instead focusing on weight and reactivity.
Fulcrum’s Speed 25 is a high-end wheelset and that’s reflected in the price. It’s available now with HG11, XDR and N3W freehubs at £1,999.99.
Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now pushing 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.