Why Our Fastest Road Wheels are Gravel Wheels

Our fastest road wheels are actually our gravel wheels. What? Yes, I had to do a double take when I processed this data in the wind tunnel. When testing our All Sport (AS) and Gravel line in the A2 Wind Tunnel, I made a last minute decision to test a 32mm Continental GP 5000 on the G700s and was surprised to find out that the G700 was faster than all of our disc brake road wheels and all but the FLO 77 AS of our rim brake road wheels.  

NACA Profiles & Cycling Wheels

Back in the day, National Advisory Committee for Aeronautics (NACA) studied wing design to learn about lift, aerodynamics, and more. What they found was that blunt, round surfaces generated great lift. An airplane wing is similar to a rim profile with a tire on it tipped on it’s side  and we learn a lot from wing research and design. 

Cycling wheels with narrow tires are much taller an thinner than a NACA shape which reduces the aerodynamic properties of the shape. NACA profiles generate great lift. A cycling wheel needs the ability to create the equivalent of lift – this is called side force – in order to be aerodynamic.

For years, I wanted the ability to design wider wheels but I was limited by frame design and had to design within the constraints that we had, which put us outside the NACA profile. If I had my way I would say “let me make an ideal wheel and build a frame around it.” But that’s not the current situation. However, that wheel looks closer to the G700’s- wider, blunter, with not such a pointy crown, and is much closer to that ideal NACA profile which means, it’s fast.

Aerodynamics Is Combination of Width & Depth

The old belief of deeper is faster isn’t always true because we now we understand that wheel profiles have been too narrow. Wider can also be faster with the proper design. For example: 

Note: Total Power is calculated by adding the total watts consumed from aerodynamics and rolling resistance, with the goal to have your total power number as low as possible.

FLO 77 AS w/ 28mm Continental GP 5000 – Total Power = 21.38 W

FLO G700 w/ 32mm Continental GP 5000 – Total Power = 20.97 W

The FLO G700 is 21.7mm shallower but 4.6mm wider. This is a massive depth difference and we still end up with a faster wheel because we added 4.6mm in width. 

If road frames allowed us to make wheels as wide as our gravel wheels, we would see large reductions in Total Power. 

The Best Kept Secret in Wheels

For road riding, I now only ride my gravel bike. Why? It’s faster, the tires are wider, I have better grip, pressures are lower, handling is improved in cross wind, and vibration is lowered. There is a long list of benefits when you ride a wider wheel. Here is my secret— if you are looking for a new road bike consider a gravel bike. Geometries are close and you give yourself the versatility of using it as a road and gravel bike, plus the frame accepts larger, wider, and faster wheels like the FLO G700’s. If you have a road bike that accepts a wider wheel, don’t buy a road wheel, get a gravel wheel. While it may sound odd, you’ll be faster because of it.