It’s an open secret that the Belgian Cycling Factory group is working on a new aero gravel bike called the Ridley Kanzo Fast. Shaped in their own wind tunnel, the new carbon bike looks a lot like a fat-tire version of Ridley’s race-winning aero road Noah Fast, so we can only imagine that this could be the fastest gravel bike we’ve seen yet…
2021 Ridley Kanzo Fast all-new aero gravel bike
Based on all the hints we’ve seen them dropping over the last week or so, it’s likely that the Ridley Kanzo Fast get an official reveal any day. Ridley has talked up the carbon blend of the upcoming gravel race bike as being a happy medium, so you no longer need to choose stiffness OR comfort. Why not both? The aerodynamic tubing profiles we see suggest a rather stiff ride, so their engineers would have had to work hard to build comfortable flex into the aero seatpost & seattube. They are calling it the “ultimate gravel bike”.
In the meantime before Ridley reveals all the new bike specs, we have plenty of information to pore over – down to geometry drawings and even some tube sections!
Here’s what we do know – Tech details
First up is tire clearance, since that’s how many of us categorize gravel bikes these days. Ridley officially claims that the max tire size of the new Kanzo Fast is 700c x 42mm, which is maybe on the narrow side of gravel these days (but up from the 38mm of the Kanzo Speed).
With that said, they’ve already been sharing a photo of one of the Kanzo Fast prototypes fitted with 45mm Riddlers, and the frame drawing they share has more than 52mm between the chainstays, so that figure is likely conservative.
Gravel Geometry
On the topic of geometry, a Medium frame is set to have very similar overall geometry to the current Kanzo Speed, with a 71.5° head angle, 73° seat angle, and 386mm frame reach. Frame stack is just a few millimeters higher, which I would probably chalk up to trying to eliminate spacers under the stem since this new aero Kanzo gets a more integrated cockpit.
The toptube is more sloping than the current Kanzos, likely to expose an extra 20mm of seatpost for some extra bump-eating flex, also helped by an even lower integrated wedge-style seatpost clamp set into the toptube. Chainstays are also three millimeters longer than the Speed’s at 425mm to fit those bigger tires.
Gravel Aerodynamics
What do we know about aero gravel? The general idea seems to still be that there are Watts to be gained, even at slower gravel speeds. The front end of this new Ridley Kanzo Fast is certainly simple and streamlined.
And obviously Ridley wanted to know just how aero it really was. This is showing at least a completed mockup in the Bike Valley wind tunnel, that just so conveniently is also a part of the Belgian Cycling Factory collective.
You probably notice no external shift or brake cables at all. That’s no accident, and likely something they pulled directly from the aero road Noah Fast, which uses Ridley’s own F-Steerer. Not needing an oversized upper headset bearing, the Ridley solution is a D-shaped steerer tube that works with mechanical or electronic groupsets.
Noah Fast aero inspiration
There’s plenty more design language from the recent Noah Fast visible in this 3D printed test mockup of the new Kanzo Fast. It gets similarly smooth fork-to-downtube transitioning, even down to the angular edge off the top of the fork crown. Plus there’s a similar wheel cutout & dropped tiny seatstays out back – even the same flat disc brake mount & captured alloy derailleur hanger/thru-axle thread insert in the carbon frame.
Built up, we can see the complete mockup with the same rubber cap over the seat clamp, the small aero fork flaps behind the front axle.
Here in what looks to be a real rideable frame, the PressFit bottom bracket is visible, as are some more braze-ons. I see full fender mounts front & rear, two sets of bottle bosses inside the main triangle, and a third set under the downtube.
Nowhere is there any accommodation for external cable routing, and no chance of running a front derailleur.
An all-new Ridley Kanzo Fast – Now we wait…
Ridley hasn’t been stingy with the details. A bit of digging here and we’ve been able to uncover a lot about the new Kanzo Fast. We certainly have had our interest piqued. So now we wait until Ridley fives us the full story on their new aero gravel bike, tells us how much it will cost us, and when we’ll be able to ride it…
Update: Want to see more of this apparently not so secret bike? Internal gear hub producer Classified has been using the upcoming Kanzo Fast to test their wireless 2x hub doubler for the past few months. And they are sharing a lot more photos of the new aero gravel Ridley.
