FLO 90 Carbon Clincher – Review

It was just over a month ago that we shared our first look at FLO Cycling’s 2016 lineup – a lineup that, for the first time ever, included full carbon clinchers. And while we are planning to review the lineup in its entirety, we wanted to start with the product that we feel may be FLO’s biggest seller for 2016 – the FLO 90 Carbon Clincher front and rear.


Initially we debated pairing a FLO 60 Carbon Clincher front with the FLO 90 Carbon Clincher rear since we know many riders will trade a tiny bit of speed (FLO says 13 seconds over an IM course) for a more manageable ride. But recently we have spent time on the Zipp 808, Zipp 808 NSW, Bontrager Aeolus 9 TLR, and the Reynolds Aero 90, so we wanted the best apples-to-apples testing experience we could get.

The FLO 90 Carbon Clincher

The new-for-2016 FLO 90 Carbon Clincher started with a simple question: what makes a better wheel? Yes, the original FLO wheel shapes were good, but could they be better. We dug into their research in our First Look at the 2016 lineup, but the short version was that Chris and Jon (owners of FLO Cycling) took nothing for granted with this new wheel shape, starting with the optimum yaw angles at which to build a wheel. Instead, they went and built a cycle-mounted computer for measuring wind speed, velocity, and yaw angle and then rode it 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.


What they found 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 original FLO wheel shapes had been designed under the assumption that 80 % of your time was spent between 10 and 20 over an even distribution. The new result is the complete opposite, with a decreasing distribution over the range. With this new data in hand, John and Chris went about designing their wheels.


The 2016 FLO 90 Carbon Clincher weighs in at 890g for the front and 1020g for the rear. The wheels are laced with Sapim CX-Ray spokes. FLO has always used CX-Ray spokes based on industry feedback, but during their last trip to the tunnel, they actually tested out the benefits. FLO tested the following wheels in the wind tunnel:

  • Front FLO 30 with 20 radially laced Sapim CX-Ray spokes
  • Front FLO 30 with 20 radially laced round spokes

The results were striking:

Screen Shot 2016-04-03 at 4.38.13 PM

Using the FLO 30 with round spokes as a baseline, the FLO 30 with Sapim CX-Ray spokes will save you 9 seconds over a 40km, and over an Ironman you gain 42 seconds.  If you take both wheels into consideration, the time savings will increase.


The FLO 90 Carbon Clinchers also feature the new FLO Vortex 2 hubs. The Vortex 2 hubs reduced the weight of the rear hubs of the 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. Staring in 2016, FLO will discontinue their TPI ceramic bearing line. After testing, FLO was unable to show a performance improvement.


As part of their design process, Chris and Jon ended up spending a bit of time at the A2 wind tunnel in North Carolina. 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 baselined 20 different tires, they chose two for their complete testing – the Continental GP 4000 S II in a 23mm size and Schwalbe Ultremo ZX in a 23mm size. Below are the results for each tire. For our review process, we went with the Continental GP 4000 S II as well.


To calculate time saved, FLO uses a Net Drag Reduction Value. A NDRV calculates a weighted average for time savings 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.

Continental GP 4000 S II NDRV

As you can see above, FLO Cycling tells us their FLO 90 Carbon Clinchers are 9 seconds faster over a 40km (39 seconds over a full IM) than the original Flo 90s (and just 6 seconds slower over 40km than the original Flo Disc). One of the questions we’ve already received is regarding the FLO 60 Carbon Clincher versus the FLO 90 Carbon Clincher. As you can see, the time differences are extremely close – just 7 seconds over an IM distance. For those looking for FLO Cycling’s fastest (non disc) wheel, the 90s are going to be what you end up riding. And for those looking for a bit more control in gusty conditions, the FLO 60 Carbon Clinchers won’t leave you yearning for that missed speed.

Our Thoughts

As long time riders of FLO wheels, we have to start with our first impressions – wow! The minute we unpacked these wheels we knew this was not just a small incremental update to the existing lineup.


Mounting the tires (as we said above – Continental GP 4000 S II) was not quite as easy as the Zipp 808s were, but this was far from difficult as well. We would call it better than average, with the tires mounting into place tightly but quickly. Roadside flats would not present the same challenges we’ve experienced with some carbon clinchers in the past. This is something we know not all our readers will appreciate, but anyone who has had a race day flat sure will!


We typically rode the FLO 90 Carbon Clinchers paired with another editor on a set of Zipp 808s. This gave us a good opportunity for subjective analysis of cross wind and braking abilities. Typically, we saw that when the editor on the 808s felt the effects of the cross wind, the editor on the FLO 90 Carbon Clinchers felt similar affects. We aren’t able to say definitively if one was truly better than the other, just that neither had an issue where the other did not.
DSC_0008Braking, was also impressive, with the FLO 90s being as good or better than the Zipp 808’s. Recently we spent time with the Zipp 808 NSWs, and while riding the FLO 90s while not quite in line with the NSWs, we certainly felt they could match the standard 808s. When riding in a pace line behind a rider on the 808s, we never felt we had to be more careful because they could out brake us. Unfortunately, we never did get a chance to test these in wet weather, so we can’t report on how they perform when the clouds open up on us.

Wrapping Up

Really the biggest factor when it comes to the FLO 90s is price. From an aero and braking perspective, the FLO 90 Carbon Clincher stacks up strongly against its rivals (only a final wind tunnel showdown will be able to show us who is truly top dog). But when you consider that a FLO 90 Carbon Clincher set will come in at $1,148 versus more than $2,000 for Zipps ($3,000 if you go with the NSWs), even a superior showing in the tunnel for the other brands may not dissuade athletes from opting to save some money, and instead invest it in a bike fit, tt helmet, or other options.

13 responses to “FLO 90 Carbon Clincher – Review

  1. Can you clarify – were you testing with 23mm GP4000S II tyres? Reason for asking being that I have a Scott Plasma and am experiencing rubbing on the frame when using 25mm versions of said tyre – I’m hoping that the 23mm ones will give me the clearance I need but don’t want to spend more money on tyres without knowing for certain! Thanks

  2. Yes it was the 23mm. With the Plasma – where specifically was it rubbing? Did you try backing out the set screws for the rear dropouts?

  3. Thanks for the review. As we discussed in the preview (60 vs 90). You went with the 90 to ensure a fair comparison to the other brands you have already tested. I also gather that you felt since riding the other 90s that crosswinds would not be an issue for your riding?

    • Hi Chris – For us it would not be an issue (at least for the editor who did the majority of review riding). The editor in questions is roughly 86kg (190 lbs) and typically rides deep front wheels. For others that are already more affected by cross winds they may want to consider a 60/90 setup.

  4. So you didn’t do any head to head aero testing of the Flo wheels vs the Zipp wheels then, or analyze any or Zipps or HEDs data against Flo’s data? Of course the cross wind experience would be similar, they are similar depths. I’m not sure how this article adds anything to the previous Flo article you posted.

  5. Build quality and costumer service is a really bad. I regret buying these rims. Structural defects that Flo cannot solve through customer service. They just propose to send you a new one and after paying customs you find out it has exactly the same manufacturing defaults. don’t buy.

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