Aero gains are the ultimate in getting more speed without cranking out more power. If you’ve already bought into the ‘Aero is everything’ mindset, perhaps it is time to look to Null Winds’ Aerodefender upper wheel fairings. Claiming to offer more speed in a headwind vs. aero carbon wheels (and more stability), the pointy carbon fiber wheel fairings have proven themselves in downhill coasting tests. And now you can pre-order a set over at Indiegogo…

Null Winds Aerodefender carbon aero partial wheel fairings

OK, hold your judgement for just a minute, and let’s take a look at Null Winds’ claims and what they say is the science behind their Aerodefender.

Null Winds Aerodefender carbon aero partial upper wheel fairings aero fenders aero gains #aeroiseverything

The basic concept is that the faster, forward spinning upper portion of a bike’s wheel & tire generates the most drag slowing the bike down. By encasing that section of the spinning wheel inside the Aerodefender partial upper wheel fairing, drag is reduced in primarily headwind conditions. And you go faster.

Null Winds Aerodefender carbon aero partial upper wheel fairings aero fenders aero gains #aeroiseverything

To test out (and prove) their system, Null Winds paired two identical aero tri bikes in a roll down test into a moderate headwind, then repeated it switching riders. The result was that the Aerodefender-equipped bike was always faster, on average 7 seconds faster per kilometer!

And now you can pre-order a set for your road or triathlon bike for a limited time through their Indiegogo crowdfunding campaign.

Aerodefender partial upper wheel fairings Tech Details

Null Winds Aerodefender carbon aero partial upper wheel fairings aero fenders aero gains #aeroiseverything

The Aerodefender partial upper wheel fairing claim to reduce the effective wind speed that the spinning wheel is exposed to, thus reducing drag and making you faster. To do that the hand crafted carbon fairings use custom hidden internal mounting brackets that attach to you bike’s fork legs and chainstays with a mix of velcro, zip ties, and alloy hardware.

Null Winds Aerodefender carbon aero partial upper wheel fairings aero fenders aero gains #aeroiseverything

The Aerodefender is available in versions for either rim brake or disc brake equipped bikes. The rim brake versions include cutouts for your brake calipers and are designed to use 23-28mm tires. The disc brake versions include more internal clearance up to 38mm tires, and can also be custom trimmed for rim brake bikes sporting larger tires.

Null Winds Aerodefender carbon aero partial upper wheel fairings aero fenders aero gains #aeroiseverything

A two-piece, front & rear pair of carbon upper wheel fairings weighs approximately 700g and is available to Indiegogo supporters starting at $500 (or ~$310 for one wheel). A cheaper fiberglass version is also available starting at $360 and weighs approximately 1000g for the set.

Null Winds Aerodefender carbon aero partial upper wheel fairings aero fenders aero gains #aeroiseverything

For now the Aerodefenders are made in the US. Null Wind has also partnered with popular West Coast triathlon shop Triathlon Lab who will stock the carbon Aerodefenders starting in early October, and will offer install services.

Null Winds Aerodefender carbon aero partial upper wheel fairings aero fenders aero gains #aeroiseverything

The Indiegogo is a flexible crowdfunding campaign and runs for one month for pre-orders. Early backers will already get their wheel fairings as early as Oct 2018, with all backers of the campaign expected to have orders fulfilled by the end of Nov 2018.

Now, go watch a ton of their expository videos on YouTube or Indiegogo, and discuss…


    • Those are little clip on airfoils that are supposed to make your spokes more aero. They can freely pivot around the spoke so they can self align with the wind direction. I’m pretty sure they were features on this site at one point. Not sure if they are from the same company as these aero fenders, or if this bike is just doubly decked out with aero accessories.

    • I have encountered these people in real life. Obsessed with marginal gains, but leave any conventional gains on the table in plain sight. You know them, aero bars on their road bike, clip on fenders, always wear a neon jacket, long socks bunched around the ankles types.

  1. That front “fender” will make handling in crosswinds an absolute nightmare. As a general rule, surface area in front of the steerer makes handling worse and surface area behind the steerer improves handling.

    • Had the same thought.

      And the pricing is hilarious. But as this is a product for triathletes it may not be too cheap or they won’t buy it.

    • I’ve found it has more to do with symmetry of drag forward and aft of the steering axis. I believe this is why the more blunt, wider aero wheels handle better in x-wind than the sharper, older profiles.

    • Right! With a full dose wheel, there is an even distribution of cross wind on each side of the axle so the front half of the wheel has some balance with the back half. This seems to put all the cross wind force at the front to the wheel so you would be fighting that the whole time.


  3. Taking a selfie with a rider then posting that as an endorsement on the Indiegogo seems a little sleazy:

    “World champion Peter Sagan appreciating our fairings mounted on a SPECIALIZED gravel bike at Sagan’s recent gravel bike Gran Fondo in Truckee, CA, May 2018.”

    • Step 1: Put one of these on a recumbent.
      Step 2: Become king of forums
      Steps 3-5: ????
      Step 6: piles of money

  4. These things re-surface every few years, and it seems always on some crowdfunding launch. Apart from a few recumbent riders, and people that ride with those little round mirrors attached to their helmets, it seems not many people buy them. Some people just don’t get it that if a product looks weird, bicycle related or not, then it will have little market uptake. Oh well, at least good for a laugh.

  5. A lot of people are scrambling to come up with a good excuse to not rain ride now that “fenders aren’t aero enough” is off the table.

  6. Where would we be if we never accepted progression? These may not be for everybody or anyone for that matter, but I personally love seeing far out innovations. More power to them and anything that inspires people to get off their ass and get some exercise. Don’t make fun of or discriminate against anyone who is out there riding any kind of bike in any gear they choose!

  7. In the top photo, the rider should wear tapered aero boots, aero helment, skin suit, TT bars. The video is almost creepy on how he talks.

  8. yeah but if they were made by enve or lightweight and somehow incorporated a ceramicspeed bearing it would be like the second coming, and lets not talk about the gravel edition minds will pop!

  9. So: the science behind all of this is perfectly sound, yet all the comments here are ridicule, driven primarily by the appearance of the thing. Jan Heine did wind tunnel testing at University of Washington and showed that conventional, full-length fenders reduce drag at the front of the front wheel due to covering the forward-moving surface of the tire, and add a little bit at the back of the wheel where the fender comes close to the road, with the two effects essentially cancelling each other out. It makes sense, then, that if you only include the front portion, this should reduce drag.

    I admit these are hideously ugly, but the two main causes of drag are tire and air friction. If someone is serious about reducing both, they should seriously consider something like this long before they start obsessing about bearing and chain friction, which are orders of magnitude less important.

    • Real world riding experience demonstrates that riding with fenders is significantly slower in anything but a tail wind. The rear half of a fender scooping air like a parachute results in far more drag than was demonstrated in Heine’s test. This is also a great example of how rare a perfectly straight-on, 0* headwind (as created in a wind tunnel) is in the real world.

      Not to mention, the fenders Heine tested extended much farther forward on the front wheel, and were fit dangerously close to the tires, than just about any readily available and responsibly installed fender does. He also didn’t test with a rear fender on. It’s pretty obvious that he conducted the test to yield the results he wanted to see.

    • I have to side with Daniel M for the analytical side. Properly implemented perhaps on a non-regulated non-UCI bike this mod does improve performance. These are used on the occasional aero auto design. Usually it is the fashion sense that kills the use of these things. I ride a Cruzbike V20 and don’t care if my bike looks a way different than 98% of other bikes. I will be adding a more subtle version of this concept to my wheels fabricated from heat formed lexan. For some it is all about riding and not looking dorky, for others the bike is more of a toy to tweak for speed improvements.

  10. “Please stop fanning the wind with your exposed upper wheel.” I’m going to spend the rest of my day looking for an opportunity to say this to someone.

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