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Belgian bike brand Ridley is going all in on gravel aerodynamics with its new Kanzo Fast. The fourth model in Ridley’s Kanzo range of gravel bikes, the Kanzo Fast borrows many aero features from its road cousin, the Noah Fast, with the goal of being the fastest bike off-road. But in addition to being aerodynamic, the bike is also the first to come equipped with the new Classified shifting system, which does away with a front derailleur and instead incorporates a two-speed wireless electronic shifting system into the rear hub.
You would be forgiven for thinking the Kanzo Fast is a road bike. At a glance, it looks like almost exactly like the Noah Fast aero bike. The tube shapes have classic airfoil shapes and a rear-wheel cutout. Additionally, the fork integrates into the downtube for smooth airflow and a sleek look and the cables are entirely internally routed. The aerodynamic one piece bar-stem also looks extremely similar to the one found on the Noah Fast, but is made specifically for gravel with 16 degrees of flare and a short drop and reach for more stability.
All told, Ridley claims a savings of up to 17 watts over a traditional gravel bike. In fact, Ridley’s wind tunnel testing shows the Kanzo Fast to only have 4 watts more resistance than its own Noah Fast aero road bike. With gravel events seeming to all be at least 100 miles, if not 200, aerodynamic features on a gravel bike make a lot of sense.
But the Kanzo Fast isn’t just a Noah Fast with clearance for 42mm tires. It has its own gravel specific geometry for comfort during those all-day events. That means shorter reach and higher stack in addition to low seat stays which are intended to impart more comfort —they’re even lower than the already dropped stays on the Noah Fast.
New Classified Shifting System
While this bike may appear to be offered in 1x groups only (and indeed, it is not compatible with a front derailleur, helping boost those aerodynamic numbers), it actually has a new rear-hub based shifting system made by a Belgian start-up called Classified. Combined with a traditional 1×11 shifting system, the Classified system provides 22 gears, the same as a 2×11 group. The idea of an internally geared hub is of course nothing new; commuter bikes have long made use of the technology to provide upwards of eight gears. But the Classified system updates internal hub shifting to offer a more robust version intended to meet the demands of high-end bikes.
Classified says there are multiple benefits to the system. It shifts in just 150 milliseconds, and can shift, either up or down, under a load of up to 1,000 watts. Classified also claims that using the system incurs no weight penalty. A 1×11 GRX Di2 quipped bike with the Classified system weighs the same (+/-10 grams) as a 2×11 GRX Di2 equipped bike. Classified also says the hub is just as efficient as a 2x setup. And of course removing a chainring and front derailleur smooths out airflow on an already aero bike.
The system consists of a few components. The actual two-speed shifting mechanism is contained in the rear hub. A special thru axle receives a signal wirelessly from a transmitter on the handlebar and then initiates the shift in the hub. And a special cassette is also required. But due to the large driver interface, the cassette doesn’t need a spider, allowing it to shave weight and help keep the system weight competitive with traditional 2×11 setups. The cassette is available in four options: 11-27T, 11-30T, 11-32T and 11-34T.
Classified is starting the roll out with gravel bikes, but says the technology would be beneficial to most disciplines of cycling, and wants to soon have the tech on mountain bikes as well as road and time trial bikes. It also has the financial backing of a certain Tom Boonen. We’re very interested to try this system and see if it is worth upgrading for.
Ridley claims the Kanzo Fast frame weighs 1,190 grams in a size medium and the fork another 490 grams. Built with Forza Vardar wheels and Shimano GRX Di2, a complete bike weighs a claimed 8.55 kilograms. There are four standard builds in addition to a frameset-only option: SRAM Rival 1x, Shimano GRX 800, GRX Di2 and GRX Di2 with the Classified system.
The frameset costs 3,000 euros, the rival 1x build costs 3,200 euros, the GRX 800 costs 4,000 euros, the GRX800 Di2 version costs 5,000 euros and that build with the classified system adds another 1,000 euros. There are also four standard color options as well as the option to customize your own colorway through Ridley’s website.
We have a Kanzo Fast headed to the Peloton Service Course, so stay tuned for a review soon.