The new FSA Metron 45 and 60 SL wheelsets get updated aerodynamic rim profiles optimized for 28mm tires, plus new PRS helical ratchet hubs that are not only lighter, but way faster to engage. But that’s not the only benefit to the new design…
Coming in tubular and tubeless clincher options, we covered all of the options and specs when they debuted at the Tour de France this summer. Check that post for rim profiles and all of the options. Here, we’re taking a closer look at the new hubs with a couple of fresh videos from FSA and our own cutaway photos…
Both the 45 SL (45mm deep) and 60 SL (60mm deep) do more than just go wider (21mm internal, up from 19mm), they’re both 5mm deeper than the wheels they’re replacing. The new shape and depth give them small drag savings with both 25mm and 28mm tires, ranging from 4.2W up to 5.5W depending on the pairing. They’re also a lot more stable in crosswinds.
Despite the deeper profiles, the rims get a lighter layup, with reinforcements at the spoke holes. It’s not just the layup itself, but FSA says they’re hand laying them with a more refined process to create a lighter overall rim that’s still World Tour tough.
New Vision PRS hubs
The new PRS hubs are lighter than ever, thanks to all-new internals, a stiff forged alloy shell, and tool-free end caps. Claimed weight for the rear hub is just 218g, and that’s with four sealed cartridge bearings inside. The front hub remains fairly standard with two sealed cartridge bearings.
The prior hubs were called PRA, for Preload Reduction Assembly, which let you tweak the bearing preload without removing the wheels from your bike.
Now, the PRS, for Power Ratchet System, swaps pawls for toothed conical rings and a helical spline system that pulls them together when you start pedaling. Not only does it pull them together quickly, the design locks the teeth together more firmly the harder you pedal.
The benefit to the design is that you’re engaging a much broader patch of teeth under power than you would with just a few ratchets and pawls, so you’ll have better power transfer under high loads. And it should be much more durable, too.
There are 72 teeth on each ring, and they say that’s good for 5º of rotation until engagement, which is 24% faster than the ratchet-and-pawl of their prior hubs, and a bit faster than a DT Swiss 54T ratchet ring.
The hub shells get a matte black finish and mostly black graphics.
2022 FSA Metron 45 SL & 60 SL specs
Both wheelsets share the new PRS hubs and spoke counts (21 front, 24 rear), with 2:1 straight pull bladed spokes all around. They come with standard and tubeless rim tape, tubeless valve stems, and a wheel bag. They also come with axle end caps for 9mm QR and 12mm thru axles, plus a 15mm front thru axle set. Choose from Shimano or SRAM XDR freehub bodies.
They say the 45 SL is a great all-rounder, and they say you can use it for everything from climbing to cobbles to gravel, even cyclocross. And they’ve had their pros racing it on all of those things. Claimed weight is 1,372g, which is almost 200g lighter than the prior 40 SL wheels. Retail is $2,319 (€2,006 / £1,705).
The 60 SL is called their “stage race” wheelset, designed for fast group rides but still light enough to work on the climbs. Claimed weight is 1,460g, and retail is $2,379 (€2,085 / £1,749).
Both start shipping by the end of 2021.