We’ve come to expect an array of beautiful tools from Birzman, but fenders? That’s a new one. But of course it’s not just any fender. No, that would be way too boring. Instead it’s a fender that tackles a problem most people don’t even consider. As soon as you slap a fender onto your bike, the aerodynamics take a huge hit. If you’re going to run a fender, why not use something that actually makes your bike faster?
Sounds crazy right? But it’s true – Birzman’s new fender is not only a faster fender, but it’s also proven to be faster than certain deep dish aero wheels and they have the wind tunnel testing to prove it…
Calling it the first aerodynamic fender, the AeroGuard comes from the same mind that brought us the Crankpump co2 inflator, as well as Birzman’s new M-torque wrench multitool. After designing the fender with extensive CFD testing, the finished prototype was taken to the Southampton University wind tunnel to test it against various wheels and other fenders. The results prove the fender to be 2 to 3 times more of an advantage over 50mm toroidal shaped deep wheels with drag numbers of 0.077 for a normal wheel, 0.076 for a deep wheel, and 0.074 for a normal wheel plus Aeroguard at a steady 30 mph over real world yaw angles (up to 12 degrees yaw which is the maximum at Southampton). Birzman’s testing goes into much more depth, but the take away is that the Aeroguard would indeed make your bike faster.
Currently limited to just a front prototype, eventually a rear will be made as well as long as there’s enough interest in the concept. But since the front makes up 20 to 30% of a bicycle’s drag, the front was the place to start to prove the function. Weighing in at 200g, the fender is a one piece polycarbonate design that pops into place with the front wheel off. Production fenders would be mounted in place would either zip ties or Velcro, with the thought being since the fender makes your bike faster you would leave it on regardless of the weather. Designed around 25 mm 700c tires and standard road brake calipers, Aeroguard should fit most road bikes.
If there is enough interest, Birzman is looking at a larger 29 mm version and a disc brake model as well. Still just a concept expect to see this hit production next year.