Kappius’s Evolution rear hub offers 1.5-degree engagement and only weighs 270g (Matt Pacocha)

One of the most interesting products on show at Sea Otter was a new carbon fiber hub with 240-point engagement and magnetically driven pawls. Designed by inventor Russell Kappius and his pro mountain biker son Brody, who’s also an engineeer, it was hard not to be impressed by the Kappius Components Evolution.

The design does have a couple things holding it back: the incredible cost of the system – US$699 for the rear hub alone – and the fact it relies on SRAM’s PowerDome cassettes. While SRAM look to be fully vested in their machined steel Red and XX level cassettes at the moment, a change would cause a production ‘challenge’ for Kappius, to say the least. 

That aside, though, the Evolution hubs are very impressive. The ultra-light weight – the rear is claimed to weigh just 270g – is sure to draw many in but it was feeling the rear hub drive a wheel that sold the design to us. The eight magnetically ‘sprung’ pawls in the rear hub engage a 60-tooth hardened steel drive ring two at a time for an astounding 1.5° engagement. 

There’s another unusual feature hidden within the shell – an ultra wide 103mm bearing stance. This is possible because the drive mechanism remains external to the hub, and should produce a stiffer and stronger wheel. 

A SRAM XX 10-speed cassette retrofit to the Kappius Evolution hub design

The hubs roll on Enduro radial bearings for now but Kappius senior says they’ll soon incorporate Enduro’s radial contact bearings. Right now, Kappius offer 9mm quick-release, 15mm through-axle front and 142x12mm rear standards, Cannondale Lefty and standard 130mm road hubs. All are available in 28- or 32-spoke drillings.

The matching front hubs cost $299, weigh 110g and utilize Kappius’s ‘differential pressure concept’, where holes in the hub
shell allow for equal pressure on either side of the bearing’s seals so that
there isn’t permeation due to differing air pressures. Kappius are four to six weeks out
for new orders, which is the result of the fledgling brand’s small-scale
production structure.

Right now, all of the parts are sourced in the
US. The machined alloy flanges come from Oregon and the hardened steel drive-rings are
made by a New York state company. The drive rings are created using DMLS (direct metal laser sintering),
which is generally reserved as a manufacturing method for prototype
production. This is reflected in the price – Kappius’s own cost on the drive-rings
is a whopping $275 each.

The pricy drive-ring

On top of this, Brady does the majority of the
carbon layup for the hub shells, and the duo do all of the final assembly by
hand. Their work isn’t complete when the hubs are, either – they must spend upwards of a half-hour retrofitting a SRAM PowerDome style cassette (the labor cost for this is included in the hub price but the customer must provide or separately purchase a cassette). So although the hubs are expensive, Kappius won’t ‘rake in profits’ based on their current production model. They’re looking to
overseas production, but that sews an even longer road for the small company.

Responding to our concerns about the hub’s reliance on SRAM’s cassette design, Russell Kappius told us that sourcing their own cassette is a plausible alternative. “We’re trying to get
some traction with some of these contacts [made at Sea Otter] to come up with
some alternatives,” he said. And at Sea Otter, people noticed. The design drew
interest from just about every major company with a hand in wheels. Some spent
hours at the booth discussing the design and some came back multiple times,
according to Kappius.

For now, however, Kappius have orders and they’re
working to fill them. Based on our quick ‘touch and feel’ of the hubs we’re
floored – they’re impressively smooth rolling and the 1.5
° engagement isn’t a subtle performance feature but a slap-you-in-the-face
improvement. Add that to their claim that the drive
mechanism is both stronger and more durable in design than anything else on the market and, well, we can start to understand why Russell has
invested his retirement savings in building this company.

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