22 speeds, one hub: Ridley Kanzo Fast gravel bike features trick drivetrain

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Ridley’s Kanzo family of gravel bikes grows by one today with the addition of the new Kanzo Fast, a machine that — as the name suggests — infuses aero shaping into its carbon frame to produce what the company claims is a 14-watt power saving over “ordinary” competitors.

Ridley has plenty of experience with aero drop-bar bikes at this point, so it’s little surprise to see that the Kanzo Fast borrows more than a few design elements from the current Noah Fast aero road bike. In fact, the Kanzo Fast supposedly even uses the same truncated-airfoil cross-sections in the fork blades, head tube, down tube, seat tube, seatpost, and seatstays.

“The Noah Fast and this new Kanzo Fast are almost twin brothers,” said product manager Bert Kenans.

Down below by the fork dropouts are Ridley’s F-Wing tab-like extensions that are claimed to help divert airflow around the front hub, and the rear of the seat tube closely follows the rear tire to provide some shielding effect.

The fully hidden cables makes for an especially sleek front end on the top-end models.

Also like on the Noah Fast, Ridley has given upper-end versions of the Kanzo Fast an integrated one-piece carbon fiber handlebar and stem, with fully internal cables and hoses that run through the stem and then down along the side of the D-shaped carbon fiber steerer tube. The bar dimensions are more tuned for mixed-terrain riding, however, with a shallower drop (120 mm instead of 130 mm) and shorter reach (70 mm instead of 75 mm) relative to what’s found on the Noah Fast, as well as 16 degrees of flare to provide more leverage and control on loose ground.

Handlebars will be offered in widths from 38 to 44 cm, together with stems ranging in length from 90 to 140 mm, although there are just four combinations available in total, which will greatly hamper sizing adjustment. Going along with that sleek cockpit are profiled split headset spacers and a similarly shaped upper headset cover — both borrowed from the Noah Fast. Lower-end models will feature separate handlebars and stems, however.

Geometry is shared with the current Kanzo Speed all-rounder model (and yes, the naming conventions are confusing).

Ride quality is almost always a concern when it comes to gravel bikes seeing as how they’re almost assuredly going to be used on surfaces that aren’t exactly glass-smooth. Ridley claims the Kanzo Fast’s dropped seatstays help somewhat in this regard (along with the 42 mm-wide rubber, of course), but there’s little in the design of the bike to suggest that it’ll be a particularly buttery ride — and the Noah Fast aero road bike on which the Kanzo Fast is based isn’t exactly renowned for its compliance, either.

Then again, it’s also possible that the Kanzo Fast could be similar to the Cervelo Aspero in being unusually adept at straddling the line between tarmac and unpaved applications. That bike certainly isn’t particularly cushy, either, but it’s nonetheless one of our favorites for riders looking for a one-bike-to-do-it-all solution.

Other details include clearance for 700c tires up to 42 mm-wide, five available sizes and four stock colors (along with custom options), and compatibility with both mechanical and electronic drivetrains.

The somewhat modest tire clearance should fine given the expected audience for the Kanzo Fast.

Claimed weight is 1,190 grams for a medium painted frame and 490 grams for the matching fork, and complete bikes are said to weigh as little as 8.55 kg (18.85 lb).

Prices range from €6,000 for the flagship model down to €3,200 to start, with availability scheduled to begin September 1. Pricing for other currencies is still to be confirmed.

A Classified take on drivetrain compatibility

The Kanzo Fast is ostensibly compatible only with single-chainring drivetrains since there are no provisions whatsoever for a front derailleur, and indeed, three of the four available build kits (SRAM Rival 1, Shimano GRX 800 mechanical, and Shimano GRX Di2) feature conventional 1×11 setups.

The top-end version, however, comes equipped with an innovative two-speed wireless rear hub transmission developed by fellow Belgian outfit Classified (which we previewed here). A small planetary gear set inside the rear hub offers both 1:1 and 1:0.7 gear ratios, essentially simulating the effect of 53-tooth and 37-tooth chainrings (or, at least, that big of a jump), but without the associated hassles.

Although there’s no provision for a front derailleur on the Kanzo Fast, the inclusion of Classified’s trick two-speed rear hub effectively provides the best of both worlds (at least in theory). Photo: Classified.

Shifts are said to happen in just 150 milliseconds and can be performed under full load. Classified tested the system in-house with up to 1,000 watts of applied power. Battery life sounds promising, too, with up to three months (or 10,000 shifts) worth of power stuffed inside the proprietary rear thru-axle (which also houses the wireless receiver). And while the system plays well with Shimano Di2 levers, we haven’t yet heard if it also works with anything else.

Classified even says its rear hub is surprisingly light. When it’s paired with a Shimano GRX Di2 1x drivetrain, it’s supposedly the same weight as a conventional GRX Di2 2x setup – and with the Rotor Aldhu crankset that Ridley has specific on the top-end Kanzo Fast, it’s actually said to be 70 grams lighter.

Friction supposedly isn’t much of an issue, either, which would be impressive given the somewhat conventional planetary gear internal architecture. In the 1:1 ratio, Classified says that all of the internal bits are moving at the same speed as the hub shell, so there’s no additional drag whatsoever. The lower ratio is claimed to be “99% efficient” — whatever that means — but even then, rider speeds will also be lower than in the higher ratio so it shouldn’t be as much of an issue, either.

The Classified hub is actually modular, with all of the gear guts contained in a surprisingly small unit that can be easily swapped into different hub shells. Photo: Classified.

Classified offers its rear hub with four different proprietary cassettes, and Ridley has wisely chosen the widest-range 11-34T option that provides an impressive 451% total range with far tighter gaps between individual shifts than you’d otherwise get with a conventional 1x drivetrain with a similar spread.

Much still remains classified

Want to know more about the Classified hub? And in particular, do you want to know what we think of how well it works? So do we. But alas, Classified has partnered exclusively with Ridley — at least for now — so the only way to get the system is to buy a Kanzo Fast.

And sorry, Ridley, but while the Kanzo Fast looks like a perfectly reasonable option for gravel and mixed-terrain riders who value speed above all else, it’s the hub that’s really got us excited right now.


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