Are carbon rims really stronger than aluminium ones?

How is carbon-fibre, with its reputation for being lightweight but prone to catastrophic failure, now being ridden routinely by mountain bikers?

In 2010 Fabian Cancellara won Paris-Roubaix for the second time. He attacked at Mons-en-Pévèle and soloed to the velodrome two minutes ahead of Thor Hushovd.

It might have been just another incredible performance in a spectacular season: the Swiss rider had already won Milan-San Remo and the Tour of Flanders, and would go on to win the Tour de France prologue and the World Championship time trial. But there was something different about this victory: it was the first time the ‘Hell of the North’ had been won on carbon wheels –Zipp 303s.

At the time it was seen as a huge technological turning point, but carbon wheels were still eyed with suspicion by the average rider. It might be fine for Cancellara who never goes anywhere without a following car packed with spare bikes and wheels, but could it really be trusted for everyday riding?

Thirteen years on the question has been answered many times over. Carbon is not only capable of withstanding the toughest terrains but wheel brands’ impact testing is now showing that carbon rims are actually stronger than their alloy counterparts.

One of these brands is West Sussex-based Hunt Wheels, which most recently has been testing its Proven Carbon Race Enduro mountain bike rims against its aluminium Enduro Wide mtb rims – and other competitor rims – on its custom impact rig, which drops an anvil directly onto the rim, with the weight and shape of the anvil and height of the vertical drop variable.

A graphic on Hunt’s website has the carbon wheels taking significantly more impact energy before they fail.