Long before the 32-inch trend swept across the globe, the Australian small-batch manufacturer Curve was experimenting with large wheels. The so-called “Titanosaur” concept bike was already rolling on 36-inch wheels back in 2019. This concept is now being succeeded by a gravel bike that is far more likely to make it to market: the Curve Big Kev of Steel 32. Curve has repeatedly shared teasers with its social media following regarding the project’s progress, and the V3 prototype is now ready to ride.
Conclusion
Personally, I’m a big fan of the radical look of thin steel tubes and chunky tyres. The large 32-inch wheels really come into their own on the Curve Big Kev of Steel V3 prototype. The frameset, hand-brazed in Australia, is a real feast for the eyes. Curve’s in-house carbon wheels, featuring the new wheel size, also demonstrate just how much development expertise the company possesses. - Jan Timmermann, BIKE editor
Details: Curve Big Kev of Steel 32
- Intended use: Gravel
- Wheel size: 32”
- Ground clearance: 2.4”
- Frame material: steel
- Price: N/A (prototype)
Made in Australia
Curve has long made a name for itself in the gravel scene with exciting prototype and small-batch bikes. In particular, bikes featuring carbon tubes and titanium sleeves, such as the striking CarboKev model, have attracted considerable attention worldwide. With the new Big Kev of Steel, Curve aims not only to showcase its many years of development work with large wheels, but also to demonstrate that the Australian company’s frame-building department knows a thing or two about traditional steel craftsmanship. The prototype frame of the new 32-inch gravel bike is built from a Columbus Zona tube set. According to Curve, Columbus’s tube profiles had not yet been adapted to the requirements of 32-inch bikes, and the frame builders had to get creative to integrate the large wheels into the gravel bike. Some of the tubes were bent, the dropouts had to be sourced as bespoke components, and the chainstay yoke was 3D-printed from 316L stainless steel.
The kit was then soldered, not welded. Soldered steel frames are considered particularly comfortable and less prone to breakage. However, compared to welding, they generally offer less rigidity. So far, Curve has not sold any steel frames soldered in Australia, but intends to use this manufacturing method solely for prototype production for the time being. It is not yet clear how close the prototype of the Curve Big Kev of Steel 32 is to series production. The 32-inch version is based on the standard Big Kev model, which comes as standard with a titanium frame and carbon fork, fitted with 29-by-2.4-inch tyres. Curve says it has learnt a great deal from its experience with the Titanosaur and considers 32-inch wheels to be the “more sensible” wheel size for gravel bikes compared to 36-inch wheels. In fact, Curve had already been considering building gravel bikes with 32-inch wheels back in 2019. Above all, however, the availability of tyres presented the Australians with almost insurmountable challenges at the time. The 32-inch steel prototype is currently being put through its paces in real-world conditions.
From 29 to 32 inches
The Big Kev of Steel 32 show bike pictured here comes in frame size L. Curve promises that, from frame size M upwards, the bike will offer the same contact points as the standard 29er Big Kev. To achieve this, not only did the head tube need to be shortened and the steering angle adjusted, but a completely bespoke fork also had to be built with the help of Moné Bikes. The prototype rigid steel fork is set to be followed by a carbon version. Other frame builders will also be able to purchase the Curve 32-inch fork for their bikes in future. According to Curve, an S frame size for the new Big Kev of Steel 32 is theoretically conceivable; however, it remains to be seen whether this will go into series production or whether it will be limited to individual bespoke builds.
Curve is using its own carbon rims to build the Big Kev of Steel 32 V3; with a depth of 45 millimetres, these are said to offer good aerodynamic properties and are also still at the prototype stage. They are paired with 2.4-inch-wide Vittoria tyres. The 32-inch gravel bike is powered by a combination of SRAM Force and SRAM X0 groupsets with a large mountain bike cassette. To compensate for the greater stack height and the longer frame resulting from the new wheel size, Curve uses a 60-millimetre-short FSA stem with a -20-degree drop. Naturally, the in-house Curve Carbon Walmer handlebars are also fitted.
What do you think: do slim steel tubes look good with thick 32-series tyres? Let us know in the comments!
Jan Timmermann
Editor