Sign up for our newsletter


Game Changer : HED CX Wheels

HED wheel
John Nelson
1 May 2015

If you think these wheels look familiar today, it's because Steve Hed got the shape right 25 years ago.

It was the 80s, and in the US it was the Wild West of aerodynamics: new frontiers,’ says Steve Hed, owner and founder of Hed wheels. ‘Aero was just coming out and I was one of the first private users of a wind-tunnel. People would call me up out of the blue, like Boone Lennon or Phil White and Gerard Vroomen – students with crazy designs who would load everything into a VW camper and drive down from Canada to get an hour or two’s testing with me at the Texas A&M University wind-tunnel.’

Lennon would go on to design the Scott Clip-On Aerobars with Charly French and Vroomen and White would start up Cervélo. No wonder Steve Hed is credited as one of the forefathers of bicycle aerodynamics, and his Hed CX is considered the original deep-section composite aero wheel.

Present and correct

Measure the Hed CX against today’s top-end wheels and you’ll struggle to spot many differences. True, the CXs are constructed from carbon composite and alloy and weigh around 2kg a pair, but otherwise there’s little to separate them, save for the date of manufacture: Hed was making the CX back in 1988. ‘I studied history and literature, not engineering, but I was a bike guy,’ says Hed. ‘Working in a bike shop after college led to a job making composite skateboards and later the first set of composite waterskis. I was also a model aeroplane guy, going to tournaments as a kid, so I understood aerodynamics too.

‘I knew that round objects were really poor aerodynamically, so the idea behind the CX was to take the tyre, being round, and give it an aerodynamic fairing behind it.’ The design was quickly copied when the CX debuted, but as Hed points out, the competition missed a trick. ‘Zipp was one of our first copiers and they were convinced you had to have a round tyre and then a fairing that went to a point, like an aeroplane wing. They never took into account that the air that goes over the front of the wheel has to also come over the back of the wheel. But from the beginning we did that very oval rim profile.’

This oval profile, often referred to as ‘toroidal’, became the go-to shape for most aero wheel brands. The CX’s dimensions would not look out of place today either. At 60mm deep and 26mm wide they’re still right on trend, not to mention the 21mm wide rim bed and curved brake track that Hed employed to smooth the transition of air from tyre to wheel (which interestingly was trumpeted as a revelation by certain companies just a few years ago).

Hed filed a patent for the rim shape in 1989 and went from turning out 20 to 30 CX wheelsets per year ‘in my garage, mostly for friends’ to making thousands, selling for $1,000 a pair (about £1,275 in today’s money). However, Hed’s monopoly was short-lived. ‘Zipp realised they kind of had to copy our shape. Then I had a falling out with my business partner [Robert Haug], and since both our names were on the patent, Zipp was able to buy the rights from him. Then, since patents in the US disappear after 20 years, an onslaught of similar wheels came along in the late 2000s.’ Yet, while that might leave a bitter taste, Hed remains philosophical.

‘Even now a lot of companies have copied our new shapes, which we’ve just gotten patent approval for in the US this last couple of months, but I’m not sure if I’m going to chase it. If you get too caught up in patents and suing people you’re not pushing on with the stuff you care about: making new wheels and pursuing those new frontiers again.’

Sadly Steve Hed passed away, aged 59, in November 2014.

Read more about: