I'm interested to see how this test pans out. The 303 and other modern wheels of a similar depth are truly the "jack of all trades" wheelset especially if you throw in a disc cover.

Preliminary data up already:

http://www.novemberbicycles.com/...nd-other-alloys.html

---

http://bikeblather.blogspot.com/

I've had a set of "Fairwheel Phalanx" wheels for a while now, which is a set of XR31T's build on DT350s + Sapim Laser. It's a really nice rim, I've been exceptionally pleased. (<$450) Good to see it's also pretty darn aero. Although the spec wheel from Fairwheel isn't identical to the tested wheel obviously.

I'm glad that I built up my front using XR-31 last year. Truth is, difference btwn these new alloy 30mm rims and 60mm tubular stalwarts (e.g. Stinger 6) is a few watts at most, and the former has good braking performances.

I especially appreciate the following from the blog entry


granted, i'm not sure if that's front wheel only, or front + rear (toss in another 5-6W), but the fact remains that wheels only look nice, but past a certain point doesn't give as much return

I'm reminded of an aero wheel test from the Augst 2016 issue of the German magazine "Procycling" that I stumbled upon while surfing the net for wheel test data. It was a bit of a pain to translate the article a few paragraphs at a time, but I did and the results were quite fascinating. They put a pro cyclist on a velodrome with various wheel sets and measured the power output it took to maintain 40 and 45kph.

No Zipps were used in the test, but the Roval C64s kind of served as the established high performance bench mark. . For curiosities sake, they included one affordable medium depth (32mm) alloy wheel, the DT Swiss R32 Spline, which I've seen online for as low as ~$360 a set, shipped. At 40 kph, the difference from the DT Swiss to the Rovals was about 6 and a half watts. I'm more like a 35kph guy, so for me I'm guessing it would be more like 4-5 watts difference. FWIW, the Swiss Side Hadron 625s ended up testing the best, a fraction of a watt better than than the Rovals at both 40 and 45kph.

A velodrome test won't tell you much about high yaw situations, but, because of the turns, it's more than a zero yaw test. They claimed the effective yaw varied from 0-5*. I was really considering spending $1200ish for some HEDs or Hadrons, convinced they'd save me a bucket of time. That test changed my mind. Now I know there's lower hanging fruit on my aero tree.

---

"They're made of latex, not nitroglycerin"

That Al33 rim.... I can't seem to find it anywhere. I'm guessing that's the rim they build up with their "RFSW3" wheel set?

GreenPlease wrote:

That Al33 rim.... I can't seem to find it anywhere. I'm guessing that's the rim they build up with their "RFSW3" wheel set?

It's their rim:
http://www.novemberbicycles.com/...-al33-and-rfsw3.html

---

http://bikeblather.blogspot.com/

Wow the AL33 did really well in that test.

November doesn't make that rim but they seem to be the first to get their hands on them for production.

Shock results just in from the wind tunnel!!! "Paying customer's product goes better than anticipated!!"
Colour me sceptical but I think the most salient point is that the difference between wheels in terms of aerodynamics aren't as great as what the "market leaders" would have us believe. Another shocking discovery.

The take away I get from that graph, when you factor in the "AOA distribution," is that the Kinlin XR31T looks like the clear winner.

---

"They're made of latex, not nitroglycerin"

Flo is a MUCH better A2 customer than any entity involved in yesterday's test, and for what it's worth we weren't the paying customer. A2 wouldn't have had any idea which wheel to influence yesterday if they were inclined to do so. But just to counterpoint skepticism, if A2 were inclined to fudge results, don't you think the Flo 30 would have done "better"? That result has the potential to piss off a customer who does a lot of work at A2.

As to your second point, yes, I agree wholeheartedly. With every hair on my head, and there are fortunately still tons of them.

Dang, I just bought Flo 30's over Kinlin 31XRt for the supposed aero property, giving up 80g each rim. I could have lighter weight and better aero properties!

Last summer I bought a Flo 30 front and built a powertap Flo 30 rear as my all around training and racing wheel set.

I'm feeling better and better about my purchase.

Been saying this stuff for years, that there is so much marketing bullshit, but this is slowtwitch......

Interesting that the Flo30 seems to stall so badly after 15 degrees in this test. Flo's data from when they were testing their new wheels shows a slight decrease in drag all the way out to 20 degrees.

Dave,

Thanks for jumping on. I have loved your blog over the last couple years. Keep up the great work!

Were same hubs were used for each rim?

rijndael wrote:

Were same hubs were used for each rim?

Yes, other than the 303s:


http://www.novemberbicycles.com/blog/2017/2/6/aerodynamics-thoughts.html

I agree that this test shows the Kinlin looking good at low yaw angles, where things matter. I'll also mention that the FLO 30 was designed in 2012 and is our only rim that has not been designed with our new low yaw algorithm. I've said for years that the only way to do a real tunnel comparison test is to get all manufacturers in the same tunnel for a "take your best shot" type of test. Personally, I think that would be cool, but I don't think many brands would sign up for that.

---

Chris Thornham
Co-Founder And Previous Owner Of FLO Cycling

Are there any future plans to revisit designing the FLO30 with the new low yaw algorithm or will it stay as originally designed?

A2 isn't in the business of fudging numbers. We've easily spent enough time there to determine that. A2 runs the tests that you ask them to run, and gives you the data. What does this mean? It means that the people designing/running the test are 100% responsible for the data/content they are producing. We've always chosen to be as transparent with our testing protocol as possible, for obvious reasons. I'm certainly not trying to take a stab at you, or suggest that your testing protocol was poorly designed. I'm just brining these points up because a lot of people don't realize how easily wind tunnel numbers can vary, even when the person designing/running the test has the best intentions. Here are a couple examples of some things we've learned and how easily numbers can be inadvertently be skewed.

1. Using the EXACT same tire. Two tires that are identical in make/model/size can vary by up to 100 grams of drag in a test. Wind tunnel time is very expensive. As a result, testers will often use two or more brand new tires and rotate between them, not knowing there is up to a 100g difference between the tires.

2. Setting Pressure. How you set your pressure matters. Our tests have shown that a difference in tire pressure of only 5psi can effect aero drag by more than 90g. Even when using the exact same tire and wheel. Why is this important? Our good friends at Silca tell us that the standard floor pump - used by many testers - has an accuracy of 5%. If you are inflating to 100psi for your test, your accuracy variance could be skewing the numbers by close to 100g of drag. This is why we use Silca's own testing rig "The Truth" for our tests. Here's a quote from Silca's page regarding "The Truth":


3. Compound Effect. Take the "bad" tire from example one, and combine it with an inaccurate reading from a floor pump in example two, and you could have nearly a 200g difference in drag, even with the best intentions.

As I said above, I think the only way to really compare brands is to have everyone at the same tunnel, using the exact same protocol and taking their best shot. We personally haven't studied Zipp/HED/Bontrager/November/etc wheels to the nth degree, so we don't know what tire, at what pressure performs best on each of their wheels. Because we don't know these facts, we don't feel it is fair to test against them.

---

Chris Thornham
Co-Founder And Previous Owner Of FLO Cycling

One major difference in test protocol vs. Flo's own testing is that November (in my opinion correctly) don't remove the tare from the wheel fixture.

Intuitively, as you increase yaw angle, one of the wheel support arms becomes "hidden" from the wind by the angled wheel, so you can see how higher yaw angle drag numbers may be lower under Flo's protocol. On the yaw angle chart this would make it look as though the wheel is stalling at a higher yaw (further to the right)

The immediate proximate cause for this test was that the new Al33 rim came out, and a big part of the story about it was "fast." We got involved with it early through a couple of fortunate timing things, and became big fans of it, which is a story for another day. It is not our rim. There is currently no rim for sale in the world that is "our rim." As I think serves absolutely everyone well, we demanded of the brand and the US importer that if they were going to make ANY aerodynamics claims about it, it needed to go into the tunnel against relevant benchmark wheels. Otherwise, we said, we would be the loudest voice against any aerodynamics claims that were made on behalf of the rim. We didn't let it drop until all was agreed. We were asked to develop a meaningful test.

Our philosophy is that any test needs a relevant anchor or baseline wheel. I proposed the 303 as a known quantity, accepted as fast, ubiquitous, but not something that we'd assume to be so much faster as to marginalize the relevance. I had to fight to get the 303 instead of the 202. In my mind, if you beat the 202, you've beaten a wheel that no one thinks is that fast so what does it even matter? The standard had to be a fast wheel, just as we held when we first tested our Rail 52 prototype against a 404 4 years ago (nearly to the day, in fact).

The other immediate thing was that the standard tire would be a GP4000sII 23. Had we used any other tire, people would rightly have been skeptical as to why not. That wasn't even a discussion. No other tire was considered because this is the standard test tire, and it's certainly among the most popular tires, if not THE one.

The Kinlin and HED wheels were included because the importer works with them, and was interested in getting data on them.

The FLO 30 was the other obvious inclusion, as it and the Zipp 101 had sort of defined the concept of the fast 30mm alloy. To not include it would have been fishy - the internet's first question would have been why we didn't. Beyond that, in announcing that the test would be done, we announced the lineup, inclusive of the FLO 30 - there was no "if it's really fast we won't include it" out clause. Nope. I wouldn't have allowed that. Quite the contrary, if it had been that standout I'd have been on the "how can we buy rims" line quick, fast, in a hurry.

As for the protocol, this was our fifth (I think) time being involved in a test. I've spent two full days there, and have more or less been completely trained in protocol by Dave S. We not only used the same tire for each run, inflated to the same pressure with the same pump, we used the same tire that we've used in previous tunnel trips. It's done enough time on the rollers to even show a tiny bit of squaring, but not everyone rides on a new tire every time anyway.

The valve stems were normalized as much as possible - alloys got used with a 48mm stem, 303 was used with a 60mm stem.

So the protocol was very sound. And again, the results were going up no matter what they were - I'd burned the lifeboats on that one. I've spent about 6 years trying to build our credibility on the internet, no chance is some test that we're project managing going to compromise that.

I think FLO's done good work. We obviously gave tremendous credence and credit to the angle distribution data you guys collected, which I think is fantastic and exactly the kind of "don't take our word for it, here's the proof" thing that people should demand.

Maybe it's easy for me to say because, again, there is no November rim in the world, but I'd absolutely welcome anyone to replicate this test. As long as the parameters are known and the protocols sound, and there's transparency, I think this is nothing but good in helping people make good, informed purchase decisions.

Why? Expense and logistics? Fear? Being chicken shit profiteers/marketing-centric charlatans? All of the above?

I agree with the sentiment in your statement. But I would add that the wheels tested ought to be tested on a slate of bikes. Four or five industry leading bikes.

This wheel only nonsense is largely just that, even as I understand the resources required and complexity involved in testing the whole system. Not that testing 15 tires isn't resource intensive.

Unfortunately, comparison aero wheel testing is about to become nearly impossible. How do you normalize a disc brake hoop vis-a-vis a rim brake counterpart? What about different types of disc braking tech relative to each other? IT'S THE SYSTEM -- they keep telling us. Well what happens when Trek and Bonty come out with proprietary braking entirely?

The best marketing revolves around bamboozling the customer into giving up more money -- preferably driven by emotion rather than facts. In the era of peak aero we seem to be getting just that from these larger companies. Where's that Cervelo P5-X white paper again?