Ridley AstrvsKanzo Fast

Comparing these two machines is a study in how gravel racing has matured over just a few seasons. The Kanzo Fast arrived as a direct descendant of the Noah Fast road bike, sporting tube shapes and an integrated cockpit meant to slice through the wind on groomed hardpack. It was, and remains, a specialist for riders who want road-like efficiency with just enough clearance—roughly 42mm—to handle traditional dirt roads. It’s a narrow-focus speed machine that works brilliantly on fast, compact surfaces but feels out of its depth when the terrain turns technical. The Astr takes those aerodynamic lessons and expands the scope. By pushing tire clearance to 52mm for 1x setups, Ridley has acknowledged that 'wide' is the new 'fast' in modern gravel. Where the Kanzo Fast struggles with chunky gravel and mud due to its tight clearances, the Astr remains composed. It maintains the racing DNA of the brand but swaps the aero-only obsession for a frame that can handle the punishing flint of Kansas or the mud of a Belgian spring without flinching.

Ride quality on the Astr is unapologetically firm. Reviewer David Arthur described it as an aero race bike on fat tires, noting that despite running 47mm rubber at low pressures, the ride remains stiff and occasionally jarring over exposed rocks. Power transfer is immediate, but you rely almost entirely on tire volume rather than frame compliance to save your lower back. The Astr is rock solid in a straight line, but the steering is notably heavy. It’s a bike that holds its line no-handed through deep ruts but feels ponderous and slow when you try to flick it through tight, winding corners. The Kanzo Fast shares this straight-line obsession but offers a slightly different tactile experience. It uses lowered seat stays and a D-shaped seatpost to mitigate road buzz, which testers found effective at damping high-frequency vibrations on smoother gravel. However, like the Astr, it reaches its limit quickly on technical trails. The handling is intuitive and predictable on open roads, yet it demands a firm hand to initiate turns. Both bikes are built for high-speed stability rather than low-speed agility, making them perfect for long-distance efforts where a twitchy front end would become exhausting.