Flo Cycling is no stranger to the pages of AeroGeeks.com. The FLO 60 was one of the first products we reviewed (and at the time, we said we “were smitten with this wheelset.”). And last year we reviewed the FLO DISC where we said: “If you’re shopping for a DISC and want a complete wheel that offers the best bang for the buck, the FLO DISC is where you should start, and end, your search. It is the very definition of Affordable Aero.”
But to be honest, in the three years we have been covering Flo, not much has changed in their lineup. Yes, they added the 30 to the original 60, 90, and DISC. But that has been about it … at least until now. Because starting today there is a whole new FLO lineup, and we are not just talking about new shapes and sizes. The team at Flo has decided that while the carbon\aluminum hybrid is a good option (and not going anywhere), carbon clinchers are where the market has gone—and Flo is going there too. But before we get into the new lineup, lets talk about how the brothers of Flo got there.
Building a Better Wheel
Beginning in 2014, Chris and Jon set out to build a better wheel. Yes, they knew the current model was good, but they wanted to do better. However, before they started working on a solution, they decided to ask the tougher question – what makes a better wheel? And following that up with the question of what kind of conditions are their customers going to face when riding?
To find out, they started building. Although they weren’t building a wheel. Instead, they were building a computer. Specifically, a computer consisting of a data logger – Onset Hobo Micro Station Data Logger, an Anemometer (for measuring Yaw Angle) called the Lufft Wind Sensor Professional Model 14521, and an Onset Wind Speed Smart Sensor S-WSB-M003 for measuring relative velocity. The final product was mounted to one of their bikes and then ridden on four Ironman Courses – Ironman 70.3 Silverman, Ironman 70.3 St. George, Ironman 70.3 California Oceanside, and Ironman Kona (Partial Course)—all resulting in 110,000 data points.
A few trends were immediately observed in those initial data points:
- The faster your relative velocity, the shallower the yaw angles you will experience.
- Until you hit 3mph, the yaw angle sensor swings unreliably.
- Drafting mimics slower riding. You still get relatively consistent readings, but there is more variance in the yaw angles recorded.
- When passed by cars, or moving into the wind after passing a structure, you see the sensor move to a dramatic yaw angle range for about a second before returning to normal.
- The yaw angle will move evenly from left to right in most conditions. Exceptions to this are during coastal rides where the wind is blowing onshore or offshore.
- Coastal rides produce a slightly higher set of average yaw angles.
- Most rides produce very similar results, regardless of conditions.
Additionally, when the data was combined from GoPro footage, they found that they could remove all yaw angle measurements that were greater than 20 degrees from the results. The reason for this was that when the videos were analyzed, the only reason a yaw sensor would produce a yaw angle greater than 20 degrees was in one of the conditions below (which are rarely seen in a race).
- The rider was passed by a car.
- The rider emerged from behind a structure blocking the wind.
- The rider was in a low relative velocity condition.
- The yaw sensor was stabilizing after experiencing any of the scenarios in 1-3 above.
So what did the final results look like?
What you see is that 50% of your time on a bike is between -5 to 5 degrees of yaw. Roughly 80% of your time on a bike is between -10 to 10 degrees of yaw. Only about 20% of your time on a bike is spent between -20 to -10 and 10-20 degrees of yaw. The old belief was that 80 % of your time was spent between 10 and 20 over an even distribution, which is the assumption the original Flo wheels were built with. The new result is the complete opposite with a decreasing distribution over the range.
With the new data came a new algorithm for aero optimization. For a starting point, Chris and Jon used the original Flo wheel shape. To that they “attached” the profile of a Continental GP 4000 S II in a 23mm size. To get the complete shape, they installed it on a FLO 30 with 100 psi. Flo chose the FLO 30 since it has an angled brake track, and the new wheels would all utilize angled brake tracks. They chose a 23mm size because it’s the fastest tire they had previously tested in a wind tunnel.
Flo then teamed up with CD-adapco to process the CFD. While the original FLO wheel shape was optimized on a single core processor in 28 days, the new shape took two months on a super computer (comparatively this would have been 1,334 days on a single processor machine). Each design was evaluated at four yaw angles, 2.5, 7.5, 12.5 & 17.5 degrees. For each yaw angle, the geometry was transformed by rotating the wheel, and then the model was re-meshed. The solver repeated this 500 times for each design at each angle. Each evaluation took two hours to complete on 32 CPUs.
The Results – Seven New Wheels
After months of modeling, optimizing, and time in the tunnel (we will get to that in a minute) the final resulting lineup is seven new wheels – four carbon clinchers (FLO 45 Carbon Clincher, FLO 60 Carbon Clincher, FLO 90 Carbon Clincher, FLO DISC Carbon Clincher) and three aluminum clinchers with carbon fiber fairings (FLO 60 Aluminum + Carbon, FLO 90 Aluminum + Carbon, and FLO DISC Aluminum + Carbon).
All wheels feature the new FLO Vortex 2 hubs. The Vortex 2 hubs reduced the weight of the rear hubs for the FLO 45, FLO 60, and FLO 90 by 50 grams and use 6802 bearings in the rear hubs. The front hubs feature the same 6900 bearings as the current lineup, and the hubs now have a matte black finish.
The new FLO DISC will feature a fully serviceable hub. If a spoke broke in the original FLO DISC, replacing the spoke was difficult. In the new FLO DISC, the hub has an access port that allows the spoke to be replaced.
All FLO wheels will come with Japanese EZO Stainless Steel bearings. Starting in 2016, Flo will discontinue their TPI ceramic bearing line. After testing, Flo was unable to show a performance improvement. And if you were familiar with Flo’s contributions to the Bike for a Kid program, don’t worry. Rather than donating a bike and helmet for every set of ceramic bearing wheels sold, Flo is now going to contribute 1% of their annual sales to the program.
Flo sent us eight wheels for initial testing – FLO 60 Carbon Clincher front, FLO 90 Carbon Clincher front, FLO 90 Carbon Clincher rear, FLO DISC Carbon Clincher, FLO 60 Aluminum + Carbon front, FLO 90 Aluminum + Carbon front, FLO 90 Aluminum + Carbon rear, and FLO DISC Aluminum + Carbon. While we are still in the middle of completing a full review, we did take initial weight measurements for all the wheels (in grams):
|Aluminum + Carbon||910||1080||1260||1370|
Prices for the complete line are (in US Dollars):
|FLO 45 Carbon Clincher||$549||$599|
|FLO 60 Carbon Clincher||$549||$599|
|FLO 90 Carbon Clincher||$549||$599|
|FLO DISC Carbon Clincher||$949|
|FLO 60 Aluminum + Carbon||$449||$499|
|FLO 90 Aluminum + Carbon||$449||$499|
|FLO DISC Aluminum + Carbon||$649|
And while we are not quite ready to share our initial impressions, we can say that the full carbon wheels feel incredible. Everything we would expect from Flo. We aren’t quite ready to say they have the stopping power of aluminum, but these aren’t the slippery fish we sometimes see with full carbon wheels.
Wind Tunnel Testing
So is the new line fast? Flo certainly believes so – and they brought their data to back it up. But before we get into the results, anyone who lives and breathes aero data wants to see the testing parameters:
- Tare was calculated and removed from all tests.
- A Mavic Open Pro with 32 round spokes was used as the baseline wheel.
- Each wheel was swept from 0-20 degrees of yaw, in 2.5 degree increments.
- The same tire was used for each test.
- The FLO DISC had the valve cover taped shut.
- Each measurement was taken twice and averaged.
Additionally, while Flo originally baselines 20 different tires, they chose two for their complete testing – the Continental GP 4000 S II in a 23mm size and Schwable Ultremo ZX in a 23mm size. Below are the results for each tire.
To calculate time saved, Flo uses a Net Drag Reduction Value. A NDRV calculates a weighted average for timesavings based on your time spent at certain yaw angles. With their 2012 wheel line, Flo considered 80% of your time on a bike was evenly distributed between -20 to -10 or 10 to 20 degrees of yaw, and the remaining 20% was evenly distributed between -10 to 10 degrees of yaw. However, based on their new data, they no longer believe this to be true. The new NDRV used the results from their data logger to calculate the average savings experienced when using the new FLO wheel line. As a baseline, Flo compared the NDRV results from their wheels to a NDRV for the baseline Mavic Open Pro with 32 spokes.
In sports as competitive as cycling and triathlon, it is all about marginal gains. When a company tells you their new product is 2-3% faster than their original, you take notice. When Flo tells us that their new FLO 60 Carbon Clincher is 22.20% faster than their previous model, you shut up and ask whom to make the check out to. With a price just $125 more than the original ($250 for the set), FLO wheels remain a serious performance bargain. Last year we called the original FLO DISC the definition of Affordable Aero. And with the performance of this new line, maybe we need to use the new FLO 60 Carbon Clincher and FLO 90 Carbon Clincher to redefine that phrase.