The UNBOUND Gravel Event has become the place for brands to tease new gravel bike products. On course last weekend were prototype gravel bikes, tyres, wheels, handlebars, and drivetrains – all being rigorously tested (and teased) to the gravel world.
Elite racer Andrew L’Esperance rode to 21st place at UNBOUND using a prototype Fox gravel fork with full aero fairings. Over the 9+ hours out on the course, Andrew averaged a rather sprightly speed of approximately 22mph (35kph).
Aerodynamics matters a great deal at these speeds and distances, so it’s no surprise that we’re seeing aero fairings on gravel bikes.
Let’s take a closer look at this prototype Fox gravel fork.
The Aerodynamic Fox Gravel Fork
The fork is covered in Fox RAD stickers. RAD stands for Racing Application Development, a research/testing arm of Fox that works with pro riders to develop new suspension fork tech.
If you look carefully, Andrew’s fork has been modified to allow the front brake cable to run from inside the stem, and into the fork steerer. It then exits out the bottom of the steerer and is taped down to the brake caliper.
Much more obvious are the aero fairings taped to the back of each fork leg. This gives the fork a whole new look and should allow gravel racers to ride faster with the same effort.
Will An Aero Fox Gravel Fork Make A Difference?
In short, yes.
Cylinder shapes have high drag force for their size. This is because cylinders are quite blunt in shape, and the airflow separates from behind the cylinder’s surface creating both a low-pressure area as well as a turbulent wake. All of these factors contribute to the high overall drag.
Just look at the difference in size between the streamlined aerofoil shape and the wire in the above diagram. The diameter of the wire is one-tenth of the aerofoil, however, both of these shapes have the same aerodynamic drag.
It should come as no surprise that forming fork legs into streamlined shapes would promote more efficient airflow. When you do the calculations, the drag reduction to the Fox gravel fork could theoretically be up to 90% – although this fork shape would be completely impractical.
The Fox 32 Taper-Cast Fork
While we’re here, let’s chat about the Fox 32 Taper-Cast fork.
At 1226 grams, the Fox 32 TC is one of the lightest gravel suspension forks available. Fox keeps the 32 TC weight low by employing a reverse arch crown design. This arch sits behind the tallest part of the wheel and essentially allows Fox to reduce mass without sacrificing any fork stiffness.
In addition, the bottom of the fork legs reveals a truss-like design to reduce weight further.
When it comes to damping adjustment, the Fox 32 TC offers more than most. There is a rebound adjuster at the bottom of the fork, and a lever ring at the top of the fork with three low-speed compression damping positions (open, medium, and firm). The compression damping can then be tweaked further using a second dial inside the lever ring.
The fork can be set up with 40 or 50mm of suspension travel, will clear a 700C x 50mm tyre, has 160mm and 180mm brake rotor compatibility, and is available with a 45mm and 50mm offset/rake option.
The Fox 32 Taper-Cast Gravel Fork costs between US $769 and $949, depending on the model. See more at RideFox.com.
