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Friday
Jan112013

9 Wheels and No Cameras

As of Tuesday of next week, we will be able to claim that all of our wheels are "wind tunnel tested." Does that mean we can raise our prices?

Our wheels are not at the wind tunnel for marketing purposes though. Believe it or not, this trip is motivated purely by R&D. We've got 9 wheels in boxes that just arrived at A2 in North Carolina, with nary a camera in sight.* To let you know what precisely we are testing, I'll start with the lineup of wheels we are sending (all of these are front wheels):

  1. Canary Thunder, our yellow solid plastic prototype of the Rail, built with 24 radial laced CX-Ray spokes (more on spoke count in a bit) 
  2. RFSC 85 w/ 20 CX-Ray spokes
  3. RFSC 58 w/ 24 CX-Ray spokes
  4. RFSC 58 w/ 20 CX-Ray spokes
  5. RFSC 50 w/ 20 CX-Ray spokes
  6. RFSC 38 w/ 20 CX-Ray spokes
  7. RFSC 38 w/ 20 Laser spokes
  8. FSW 23 2/ 20 CX-Ray spokes
  9. Zipp 404 Firecrest Carbon Clincher w/ 16 bladed spokes

Every wheel will be tested with the same 23mm Vittoria Corsa Evo CX tire rotating in the same direction. A single tire will be transferred from wheel to wheel to eliminate any variability that might result from variations in the tires, even if they are the same make and model. 

Curiously, Canary Thunder has 24 spokes. No, we do not intend to go to market with that many, but have you ever tried building a wheel with a 20 pound solid plastic rim? We get one bite at this apple and the extra spokes help ensure the wheel will remain true at the tire pressure and rotational speed needed for the testing. We realize it will skew our data to the unfavorable side, but we're fine with that as we're looking to get smarter in the tunnel, not proclaim ourselves the victor when we emerge.

You will see also that we have a pair of RFSC 58s, one with 20 and the other 24 spokes. Testing both of these will give us some insight into how much drag is attritutable to 4 extra spokes. Everyone assumes fewer spokes are less drag - won't it be nice to know by how much? We think so. Testing 20H vs 24H will also help us normalize the testing of Canary Thunder by extrapolating the data to suggest how CT would perform with 20 spokes (and start to build a hypothesis about what 18 would look like).

We're testing every depth of our carbon rim for two reasons: 1) we want to be able to give quantifiable response when someone asks what is the difference between this depth and that. We can say that the shallower rim sheds a certain number of grams, and by providing the aerodynamic delta as well we think our customers will be better able to calculate their personal trade-off between speed and light weight; 2) we are not fully convinced a range of 4 (or even 3) different wheel depths is warranted. As we move from open mold to proprietary designs, we will likely remove offerings that offer variety with no real additional value. 

Note that we also have a pair of 38s in there - one with CX-Rays and the other with the less expensive but same weight Lasers. CX-Rays are provided standard on a lot of wheels because of their purported aerodynamic benefit. How much is that benefit? Does it justify the additional expense? Let's find out.

Our FSW in our new 20H front skinny build also made the trip. We sent the 20H so we can compare it to comparably built carbons in different depths. It made the cut in part for baseline purposes. Most of the testing you see uses an alloy wheel as a baseline. But that wheel is usually a 32H Mavic Open Pro (front, no less!) that is about as suitable a benchmark for a performance wheel as Toyota Sienna is for a sports car. Our FSW is an outstanding wheel, but is not what anybody would consider aerodynamically remarkable. So let's see how all the carbons stack up against a racing quality wheel that isn't even trying to be fast. (And in the process, let's see how fast the FSW is in its own right.)

Finally, we've sent a Zipp 404 Firecrest carbon clincher. There are a host of reasons for this choice alone, most of which have to do with benchmarking - our current wheels against a Zipp with the same tire (and not the 21mm Zipp uses in their own testing but nobody uses on the road), our Zipp data against everyone else's Zipp data, and our new proprietary design against Zipp's recognized shape. We have no idea what to expect, but also nothing to fear. Does anybody expect our wheel to beat Zipp's? Spoiler alert - with 24 spokes instead of Zipp's 16 and a rough plastic surface that is not nearly as slippery as smooth carbon, our prototype will not be faster than their production wheelset. But this is a training race for us, not one where we expect to win. We just want to see how much work we have to do, and gauge our design's potential.

So while Canary Thunder is the impetus for this trip, we hope to learn a lot about how much a difference additional spokes, rim depth and spoke shape make, completely independent of whether we are on target with our prototype. We'll share what we learn here.

*Not entirely true. We asked the guy who runs the bicycle business at A2 and who will be conducting our tests to snap a couple of pictures of "Canary Thunder" with his phone.

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Reader Comments (8)

Gentlemen, the lineup you choose is excellent. That coming from an engineer/scientist. But I have two questions for you guys.

1) Why no tubulars? It would be an interesting comparison to see a tubie vs. a clincher since the shapes are slightly different (more so on the 38s than say the 58s).

2) Is it "the" Rail or "The" Rail? I think "The" Rail makes it a little more impressive, imho.

Brian

January 11, 2013 | Unregistered Commenterbrian

Hi Brian -

Thanks. We wanted to send clinchers for a few reasons. First we wanted to get the whole range. 85 vs 58 vs 50 vs 38 vs FSW vs Rail vs 404 is much more valuable to us right now than 38c vs 38t is. Well that's really the big reason right there. Also the Rail is only clincher at least to start with, so 38t vs Rail is kind of compromised data. Also, it's been shown that tubulars and clinchers of the same design do very similarly in the tunnel. The question of whether tubies or clinchers are more aero is a valid one, its just not the most pressing one for us right now, and at what this little camping trip is costing us we can't afford any non-critical questions.

For the second question, we don't know. It's gone back and forth a bunch of different ways. The name's stayed the same from the first moment - it was the first one we came up with and we knew we were keeping it from that moment, but whether its The Rail, or the Rail, or something else, no sé.

January 11, 2013 | Unregistered CommenterDave Kirkpatrick

"The Rail" (including quotes) would be an awesome decal on the production wheel.

January 12, 2013 | Unregistered CommenterMike

I love geeking out about this stuff; looking forward to seeing the #s, and how they diverge from my expectations. The Rail, in Spanish = "el riel", and it sounds much cooler rendered in this language. Please consult you 'Marketing Department'. In for a water bottle, if you use it....

January 12, 2013 | Unregistered CommenterRico

Just as long as you do not say something stupid like you will save 47.385 seconds compared to the Zipps, then I am game to continue reading...

January 12, 2013 | Unregistered CommenterBill

Bill -
We're going to quantify the results and what they mean as clearly as we can. However we do quantify it, you already know that our baseline will be a lot more meaningful than comparing it against "a popular OEM wheel" or "a traditional 32 spoke box wheel." We're going to do our best to make the data useful and informative to everyone.

Mike and Rico -
Noted. Thanks

January 14, 2013 | Unregistered CommenterDave

I am very intrested how much will be difference between Sapim Laser and Cy ray spokes.
And new rim against ZIPP .
Regards
Greg

January 15, 2013 | Unregistered Commenterkavitec

Greg -
Lots more information coming out over the next several days. Stay tuned
Dave

January 16, 2013 | Registered CommenterDave Kirkpatrick

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