The Wind Cries Tunnel

A boring weekend in the life of 34s, what with our budding NRC star enjoying a well-deserved weekend with her toes in the sand and a fruity blender drink in her hand.  Lacking any local races to do myself, I took my 34s for a 70 mile cruise of the south coast, whereupon I averaged comfortably in excess of 20mph and reconfirmed that if solo centuries were a valid from of racing, my standard of mediocrity would be several levels higher than where it currently stands.

Your guess is as good as ours

In addition to shipping a bunch of wheels (sun shining, hay making, etc) we're currently prepping our next trip to the wind tunnel, which will take place soon.  This will be the first time we've sent a pair of 34s, and we're doing better than sending one - we're sending two pairs.  One of the burgeoning questions around disc brakes on road bikes is how well or poorly they perform aerodynamically.  While the results should stand as a definitive answer for "how does a 24 spoke 34 equipped with disc brakes compare to a 20 spoke 34 equipped for rim brakes," it will be a pretty good proxy for the general question of "what's the aerodynamic cost of disc brakes in on wheels in general?"  The wheel we're sending has a White Industries CLD hub, using a 160mm SRAM rotor.  Tunnel time costing what it does and our interest in this question being enough to send a disc-ready 34 but not enough to exhaustively test every conceivable permutation out there, this will be what we test.  

As we've said a bunch of times, the mandate of the 34s is quite a bit beyond simply being an aerodynamic sensation.  That's way higher up on the job list for 52s than 34s, so while verifying the speediness of 52s before we put them into production was an absolute requisite, it hasn't been so urgent for 34s.

This will also be the first trip that a production 52 has made to the tunnel.  If you'll recall, when we first tested the 52, we sent our pre-production prototype, fondly dubbed Canary Thunder.  Canary Thunder had 24 spokes rather than the standard 20, and was a little rough of finish.  We'll be testing it against the same benchmark 404 that we send last time (same wheel exactly, as correct protocol would mandate), so we'll have a good reference benchmark back to the original test.  This will give us a slightly dirty answer to the question of how 4 extra spokes affects a 52 specifically, intermixed with some noise about how a yellow plastic prototype compares to a full production wheel.  

There will be a few other wheels making the trip, some of which will be making multiple runs to answer more of the world's burning questions, and you can be sure we're going to drag this one out into a bunch of blogs to ensure that any at-work time in July that you're not spending glued to the Tour will be spent glued to this site.  As it should be.

How about that Talansky, huh?  

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Did you ever send Rails out for brake track heat testing?

Joe Ajello

I'm very happy (and quite surprised) with how aero my 34s are as compared to my FSW23 alloys (23mmx28mm).Any plans to take an FSW23 to the tunnel as well to get data for all your wheels?


Seems like one of those Bluetooth non-contact infrared thermometers would be able to give some idea of the rim temperatures involved, especially combined with Strava and some data logging.

Joe Bond

pyf – We'll be doing a few things with tires, and yes a 4000 will be in the mix. It is, however, not valid to assume transferability of one test in one tunnel to another test on a different day in a different tunnel. You can't do that. This is why we sent a 404 to tag as our baseline, and why we will be sending the same exact wheel again as the baseline. When we test this batch of wheels, they will each take runs with the exact same tire – the tire gets moved from wheel to wheel. There is enough noise between two different units of the "exact same tire" to produce invalid test results. We've never compared against wheels that we didn't directly test in the same batch, we're not going to start, and we'll continue to insist that you can't do it. There's one site that amalgamates a bunch of published tests done at different times, different tunnels, different production lots of the "same tire," non-synced inflation pressures, perhaps different tires altogether, etc. I wouldn't call the data there completely worthless, but it's close. You can look at the shape of the curves, but the absolute values of data that come from different tests are not comparable.


What tire will you test with this time ?IMHO for the sake of comparison with other manufacturers datas a Continental GP 4000S II 700×23 would be a smart choice…Thanks for sharing as alwais ;-)


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