Kappius Integrates Cassette Into Hub Design With Trick Carbon Cutout Shell
By rethinking how the cassette mates to the hub, Kappius Component’s new design stretches the hubshell almost end to end, placing the wheel bearings at the outer edges to increase strength and stiffness. The extra room also gives him room for a tremendous number of pawls and a massive carrier bearing for smooth coasting.
The idea came about four years ago a he wondered why there was so much unused real estate under the cassette.
“In a normal hub, the driveside bearing is in a terrible place because of the stresses placed on it,” said founder Russ Kappius. “Our wheel bearing is placed way further out so it’s much stiffer. The bearings out the outer edge of most freehub bodies on other hubs are just carrier bearings and not structurally supporting the wheel or rider.”
It uses a slip on system built around the Cluster Core one-piece base for the cassette. He does it by milling out “unnecessary material” on the XX for mountain bike and X-Glide and Powerdome road cassettes. The Cluster Core has only a short splined section to hold the bottom one or two cogs, necessary because of SRAM’s cassette design. Once on, the lock ring no longer needs to be remove because the core simply slips on and off the hub body, held on by the axle end caps. That makes cassette changes super quick without needing a chain whip or cassette tool, just a cone wrench to remove the axle end caps.
Engagement comes from four paired pawls catching 60 teeth. They’re set so that each pair is offset 1/4 tooth length from the next pair, effectively giving you 240 points of engagement. That equals 1.5° of engagement, which is damn quick. The pawls are magnetically sprung using rare earth magnets to push the pawls against the teeth. Kappius says they did this because it’s fewer moving parts, they won’t wear out and it’s just simpler and provides consistent pressure.
The hubs are built on a 17mm axle and use end caps to fit standard quick release and 15mm thru axle front. Lefty is also available as a distinct hub. For the rear, there’s 135 QR and 12×142. For road, there’s just standard QR.
Shown above, you can see the wheel bearing on the inside edge of the red freehub body. Kappius says in most instances, this is the outermost driveside wheel bearing, which is not in the best position to carry the load put on a rear wheel. With his design, the driveside wheel bearing is integrated into the cassette core and is very near the edge of the axle.
The hub shell is oversized to improve stiffness by raising the hub flanges for a better spoke bracing angle. The cutouts are both cosmetic and functional. Kappius says heat can build up inside the hub, which can put pressure on the bearings. The issue is when it cools, the differential pressure can pull contaminants into the bearings. It’s a subtle thing, but it doesn’t hurt anything since the beating faces are still protected from direct contact with pressure washing or the elements.
Rear hub on a Specialized Crux Disc cyclocross bike.
Front hub on the bike.
Front mountain bike hubs in Lefty and 15mm thru axle configurations. No 20mm front or 150mm rear options at present.
Rear hub is $699 and reworked cassettes are $300 (XX), $250 (X-Glide) and $225 (Powerdome). If you look, these cassette prices are darn near suggested retail for these cassettes anyway, and if you purchase the hubs and send in your cassette, he’ll adapt it for free. Front hub is $299, road or mountain with any axle configuration.
The singlespeed core is $75 and can be used with any cog brand that’ll fit on a normal freehub body.
Front hub weights are 111g for both 15mm thru axle and Lefty. Swap end caps to make the 15mm TA version into a 9mm QR hub and it’s 113g.
A standard XX cassette is 209g and his adapted version is 225g. The QR rear mountain bike hub is 277g. A complete road rear hub with skewer and X-Glide cassette is 489g.
We’re hoping to test a pair out soon, but just feeling how quick these engage (and how gloriously loud the whine is when spinning the cassette) is really cool. Kappius’ son is the engineer and they’re made in the USA, making it a good ol’ homegrown family business.