About the History
Recent efforts of the bicycle industry to reduce drag have been largely directed toward the development of very expensive aerodynamic wheels, which are often made of carbon fiber. Wheel rims have become deeper, heavier, and with fewer spokes, all with increasing expense. Our Upper Wheel Fairings are generally more effective - and economical - than these expensive aero wheels, since wheel drag is actually concentrated only on the uppermost wheel surfaces. Even so, bicycles using these expensive aero wheels will also become faster with our Upper Wheel Fairings installed.
This claim may seem a bit hard to believe. At first, I also had trouble comprehending the significance of this innovation. So please let me share a little history of my discovery.
Fairings mount screws slip easily beneath fairing stay during removal
As an engineer, I was already aware of the wind profile across a vehicle wheel: where the wind is null at the ground level and up to twice the vehicle speed at the top. Since the ground is not moving, there can be no wind at the bottom of the wheel. Where there is no wind, there can be no drag. This point is often overlooked.
And the upper section of the wheel moves forward against the oncoming headwind, thereby magnifying the effective wind speeds. At first, this insight can seem a bit confusing since the wheel itself moves at the vehicle speed. In fact, we have noticed incorrect diagrams of this wind profile sometimes published in the engineering literature. So the true wind profile across the moving wheel is the first thing to keep in mind.
The second point to understand is the relative drag sensitivities of various wheel surfaces. Since I was once a paraglider pilot in southern California, I was also keenly aware how significant drag can be on the thin lines used on a paraglider wing. In fact, in the early days of the sport, I used to spend long hours modifying my own glider with extra-thin cascaded lines in order to fly faster.
Spokes are like thin lines, with relatively high drag sensitivities. However, spokes above the axle of a wheel are moving forward must faster than the vehicle, which dramatically increases drag and the power needed to propel the vehicle. So it seemed logical that these upper wheel surfaces needed to be shielded from headwinds. I began to wonder why I did not see upper wheel fairings on bicycles. When I started searching for prior art on the internet, I was quite surprised that I could not find anything. So right then I decided that if no one else was going to investigate this concept, I would.
Original Prototype with 36 spoke-count wheels
I quickly fashioned some crude fairings to my 35 year-old heavy road bike. Since I had not ridden a bike in many years, I was shocked the first time I managed to test my old bike fitted with crude prototypes of upper wheel fairings. I simply could not understand just how I was now able to ride the same old heavy bike - configured with crude upper wheel fairings - in at least one gear higher than when I was more than 35 years younger. My bike weighed more than 25 lbs and had high, 36 spoke-count wheels. Though I did not fully understand the reasons, I knew at that moment that I had discovered something significant.
My next step was to purchase a modern low spoke-count carbon-frame bike. After testing both bikes on the same six-mile loop, I found that my old heavy bike with the fairings was just as fast as the new modern bike without fairings. The difference over the 22-minute loop was just a couple of seconds. Imagine my excitement, as I knew right then that I had likely discovered something fundamental about the wheel.
Poor-man's wind tunnel test fixture
From that point, it was simply a long effort to conduct further tests and understand the mechanics of this innovation. I designed a crude fixture to test a bicycle wheel driven by an electric motor on the top of my truck, functioning as a poor-man's wind tunnel. A friend - a retired aerospace physicist - joined my effort in the Lancaster desert to help record data over a wide range of wind speeds, up to 55 mph. We measured definite reductions in drag on the wheel, but not enough to explain the speed gains that we were measuring during on-the-bike road tests. This was a bit puzzling.
Reliable co-pilot, recording the data
As a mechanical engineer, I decided to reexamine the published literature for the mechanical models commonly used to model drag on a bicycle wheel, and quickly found a problem. The engineering community seemed to misunderstand precisely what was happening when a wheel is used on vehicle. Past studies claimed measured gains using wheel fairings were marginal at best. However, the proof that these conclusions were incorrect was in the data from our own bicycle road tests.
It did not take long to understand the correct mechanical model for drag on a vehicle wheel, which forms the basis for an extensive patent application, which is now pending. After considerable effort to prepare and file the patent application, we remain confident that the application will prove successful. High-speed vehicle wheels have been around for nearly 100 years without this simple innovation. It is time that the drag-reducing benefits from using our Upper Wheel Fairings are introduced to the world.
Sea Otter Bike Festival, April 2013
We introduced early prototypes for the first time at our booth during last year's Sea Otter Classic 2013 bike festival near Monterrey, California. While riding our demonstration bikes both with and without fairings, a number of riders experienced dramatic reductions in drag. We received only positive comments from riders. Nearly everyone wanted to know when our product would be available. At Sea Otter, we even met an inventor of the mountain bike, who came to our booth to offer his congratulations for this innovation.
Pro rider explaining unexpected crosswind stability to Garth Magee
Also at Sea Otter, a professional rider from Ride 2 Recovery who was also concerned about rider safety for his veteran riders, reported enhanced stability in the presence of crosswinds. While he noticed crosswind forces on his body, he reported sensing no corresponding sideways increases on the bicycle, and found this puzzling. While enhanced stability was not our primary goal in the development of this innovation, it is readily explainable: Upper Wheel Fairings actually enhance the effective traction of a vehicle. Any potential crosswind forces caused by the addition of our Upper Wheel Fairings is largely offset by the enhanced tire traction. Bicycles fitted with our fairings are often more stable in gusty wind conditions.
Steel-framed road-test bike with 32 spoke-count wheels
Since the spring of 2013, we have refined the early prototypes into a smaller production design that can be fitted to most traditional road bikes. The proper drag model indicates that in most cases, the smaller design is actually more efficient than the early prototypes. We have been using this design to conduct a number of precision road tests, in order to confirm the performance gains.
As mentioned, the measured gains are dramatic. Racers tell us that a five percent increase in speed is a huge increase for a bicycle. And most tests have greatly exceeded five percent. Most racers find our claims are hard to believe. For this reason, we have used the latest precision power meters, which also measure headwinds, to record our data outside under real-world road conditions. Detailed test reports are available on our website. And many more tests are planned this spring and summer.
Upper Wheel Fairings Test - LA Velodrome from Null Winds Technology on Vimeo.
One of our first independent tests was indoors at a Velodrome near Los Angeles last fall. For various technical reasons regarding the instrumentation that was used, the reported data was inconsistent and unrepeatable. However, the test rider - a top-level Category-1 racer - reported that the faired bike definitely felt faster under null wind conditions. When asked, he indicated that he definitely preferred the faired bike to the unfaired version. While disappointed that we did not get good data, I knew that the drag model predicts only minimal gains under null wind conditions anyway.
First i-bike Newton data from France
One of the first independent tests conducted outside in strong headwinds was by former road racer living in France, who is now a venture capitalist focused on the bicycle industry. He had contacted me last fall, and I sent him the first early set of fairings. After hurriedly installing the fairings himself over the weekend on his own bike, he reported gains of "two or three" miles an hour the next day. And late last year, an active road racer testing in a strong headwind near Lancaster, CA was excited to experience similarly dramatic gains.
Bike Road Tests - Extreme Winds from Null Winds Technology on Vimeo.
So far we have installed our fairings on the regular commuting bikes of a number of veteran cyclists. All have reported immediate increases in speed when facing headwinds. The first local commuter to try the fairings was a bike mechanic, who reported shaving nearly 10 minutes off his 45-minute commute into headwinds toward his job in Santa Monica. Another veteran rider also reported setting a personal best on his second commute to work. Still another extreme distance racer put over 800 miles on his bike in January, without having to adjust the initial installation of the fairings at all. He also reported having changed a tire once without needing to remove the fairings.
Bikes of some early testers
All these reports have been encouraging. However, the proof is in the test data. We have now obtained confirming data in sufficient quantity to be certain that the gains are readily achievable.
Proper drag model indicates potential for rapid increases in speed when facing even light headwinds, consistent with results from road tests. Weaker riders gain relatively more, and are located to the right on the curves for a similar headwind.
Bill Brytan reports around 20% increased range in headwinds. He states that his e-bike feels more stable in 20 mph cross winds. (May 15, 2014)
A LETTER FROM OUR FIRST CUSTOMER
August 29, 2014
I've now got a few rides under my belt now with the Null Winds Upper Wheel Fairings mounted. All were local rides, 30 to 60 miles. The tour up the Pacific Coast is coming up as well.
The Upper Wheel Fairings are keepers. I won't ride again without them.
Perceived effort: Very noticeable difference. The closest thing I can compare it to is riding with both tires 15 pounds underinflated for awhile, then finally pumping both up to the maximum. Very enjoyable improvement. And the improvement is on everything except hills over 2%, where gravity takes over as the main drag.
On several slight down-hills where I normally always ride on the middle chain top gear, I found myself needing to shift up to the large chain-ring to keep the pedals at pace with my groundspeed. Yeehaw!
And the Newton supports the results. I haven't done detailed analysis yet, but on known routes I'm 1- 2 mph faster at 200 watts, flat surface, approximately 18 mph. I did do some quick mental calculations, and on a typical 8-hour day I'll be saving around 20-30 minutes of riding time. That's major!
This is all with my full rig, loaded, total combined weight of rider, bike, trailer and all gear at approximately 260-270 pounds. Which satisfyingly proves that hunch I started having few years back on a trip where I moved my front panniers to on top of my trailer. Wind resistance is a much larger factor than weight on flats and downhill.
Of course going uphill, the extra 2 pounds is there but worth the weight for the improvement. And I am going to find a way to shave that 2 pounds off of my camping gear.
The other issue I was wary of was stability. Would the fairings be solid and remain stable on rough roads, in side-winds, etc.? The nylon locknut mounting arrangement pays off; after several trips on difficult roads they are solid. The fairings will vibrate slightly in some conditions, but much less so than I had expected. There is definitely an increase in sensitivity to side gusts and large vehicle blow-by, but after awhile of becoming tuned to it, I found it to be predictable and second nature. I just had to 'retune' to it.
And what's reduced is that 'fist in the chest' feeling with a direct headwind gust. I still do feel a direct gust on my chest if I'm on the tops, but the accompanying brake-slam on the bike doesn't happen.
The mounting was finicky: I'm fussy, and of course I have a more complex mounting arrangement, since I also have fenders brackets, rear rack trunk brackets, and mounting stantions built into the custom Marinoni carbon forks, which I had to work around. So mounting took approx 6-8 hours, undoing and redoing trying different approaches, until I got what I wanted, threading through the other brackets while also achieving minimal clearance with the rims.
Another issue is when I tried to slightly bend one of the fairings to optimize the shape, one of the rivets popped so I replaced the rivet with a small flat bolt and nut.
But man it works! Very much enjoying the improvement.
Thanks for this excellent and surprisingly overdue idea. I will send you pics of my rig on my Pacific Coast tour next few weeks.
And thanks also for your recommendation of the Newton power meter. It verifies what I'm feeling in my legs when using the Null Winds Upper Wheel Fairings, and is another valuable addition to my training and riding.
Weight 190 lbs
Location: Vancouver B.C. Canada
Cycling 50 years (yikes! I must be old)
Type: Cycle tourist, self-contained. Bob Yak trailer + trunk bag.
Average tour: 1000 km., plus regular 100 km. day rides for training/fun. Intend to do cross-country next year.
Bike: Custom Marinoni Turismo Extreme
Tires: Schwalbe Marathon Super
Total weight of rider, loaded bike, trailer and all gear/food: Approx 265 lbs.