I designed 29ers – 32-inch wheels could drive innovation, but the bike industry must learn from the past, and fast

The evolution of wheel sizes in cycling is once again at a pivotal moment with the emergence of 32-inch wheels, particularly in gravel racing. The author, a former bike designer and early advocate of 29ers, reflects on the journey from the initial adoption of larger wheels to the current experimentation with even bigger diameters. The recent victory of Swiss endurance rider Robin Gemperle at the Unbound Gravel 350-mile race on a 32-inch wheeled bike has brought this trend to the forefront, despite the bike manufacturer Scott declaring their model “will never be released.” This development signals a potential shift in gravel and mountain bike design that could drive innovation but also raises questions about practicality and inclusivity. Historically, the introduction of 29-inch wheels revolutionised mountain biking by offering better rollover capabilities and improved handling compared to the smaller 26-inch wheels. Early attempts to simply scale up wheel size without adjusting frame geometry led to less-than-ideal bikes, but the second wave of 29ers in the 2010s embraced new design principles such as longer reach and slacker head angles, which resulted in more capable and better-riding machines. The gravel scene has since adopted similar wheel sizes, with riders gradually moving from 27.5-inch wheels to 29ers, reflecting an incremental but significant evolution in bike geometry and performance. The current push towards 32-inch wheels, however, risks repeating past mistakes if the industry fails to innovate holistically. Critics, including Cycling Weekly’s Tech Editor Andy Carr, argue that 32-inch wheels are impractical for smaller riders without a complete redesign of frame geometry, limiting their appeal primarily to taller cyclists. The author concurs that the industry must avoid forcing these larger wheels into existing bike frameworks, which could stifle innovation and alienate a large portion of the market. Instead, a bold rethinking of geometry and manufacturing processes is necessary to fully realise the benefits of 32-inch wheels. The lack of clear scientific evidence supporting the advantages of these larger wheels further complicates the situation, highlighting the need for rigorous testing and transparent communication from brands. Looking ahead, the author urges the cycling industry to learn from the incremental yet sometimes hesitant adoption of 29ers and to act decisively with 32-inch wheels. Clear data demonstrating the advantages of bigger wheels for specific rider profiles and conditions must underpin any widespread transition. Moreover, manufacturers should be prepared to embrace radical design changes rather than attempting to fit new wheel sizes into outdated templates. This approach could unlock exciting new possibilities for bike performance and rider experience, but it requires a willingness to challenge established norms and invest in innovation without fear of short-term commercial risk.