High rollers

Could bigger wheels improve your gravel riding? We test some oversized 750d rims to find out

- Liam Cahill

A new, bigger wheel size has been introduced, called 750d. With brands having largely settled on 700c rims for road and gravel bikes, except for a few exceptions using smaller 650b wheels, why do we need this new standard? I set out to analyse the theory behind it and find out how these new wheels ride.

The theory

When 29-inch wheels (700c rims with bigger tyres fitted) entered the world of mountain bikes, the internet melted. Although they promised more speed and better rolling over roots and rocks than traditional 26in MTB wheels, many riders decided they hated them before they'd even tried them – as with most new standards in the cycling world. Eventually though, the benefits became clear, 29ers were widely adopted – first by the Lycra-clad cross-country crowd, then by trail riders and eventually by downhill racers too – and 26in wheels became the preserve of dirt jumpers and kids' bikes.

According to their proponents, including brands such as WTB, Moots and Merit – who make the Jumbo 750d bike I used for testing – the theory behind bigger wheels for gravel bikes is essentially the same. The larger diameter of a 750d wheel should help it roll more easily over rough terrain, while the additional inertia of the bigger wheel could help you retain speed. Since the extra diameter creates a longer tyre contact-patch, 750d wheels are also claimed to increase grip, leading to better braking and handling. An additional benefit is that bigger wheels help when it comes to custom builds for taller riders. Merit, for example, feel that “in L-XXL sizes the [Jumbo gravel] bike looks best with 750d [wheels]”.