November in the wind tunnel, part 1

Today was one of the most interesting days in my life, and I started it by oversleeping.  Late-shifted daylight hours, a comfortable bed, good blackout curtains, and no yammering birds saw me sleeping past 6am for the first time since sometime in the mid-aughts, and had me behind the curve driving from Blowing Rock to Mooresville.  Well, when in Rome, they say...  I made it in plenty of time.  

We've got a few things to finish up, so while we can't yet start publishing what we learned, I thought it would be fun to go through the logistics of a day in the tunnel.  

We got 17 runs in today.  That might be some kind of a record.  Wheels we tested were: Rail 52*, Rail 34*, Zipp 404*, Enve 3.4*, Pacenti SL23^, Kinlin XC279^, Rail 52 Disc^, Rail 34 Disc^.  Wheels with a * were tested with both 23 and 25mm Conti 4k tires, wheels with a ^ were tested with a 23mm Conti 4k only.  Rail 34 Disc was tested with a full positive and negative (-20* to 20* in 2.5* increments) sweep, everything else was done from 0* to 20* in 2.5* increments (update - Wednesday morning we tested a Rail 52 Disc through a full sweep from -20* to 20* with both a 140mm and a 160mm disc since I wrote this).  We then tested the 34s, 52s, and a 34 front/52 rear combo on my Wheelhouse.  Those were done with a 23mm tire front and 25mm tire rear.  Finally, we started to run all those bike/wheel tests with me on the bike, whereupon we found out that I move around too much to be a usable pedaling dummy.  I got ants in my pants and I need to dance, I guess.  

Accomplishing all of this in one day made for a crazy busy day.  You only use one of each tire that you're testing with, so a lot of the day is simply swapping tires from one wheel to another.  We had a good system where we'd run one with on its 25mm tire test while swapping the 23 from one wheel to another, which erased a ton of potential downtime.  At one point, I was inflating a tube (they have a compressor-driven Prestaflator, I'm getting one) and the tube failed.  I thought I must have pinched it somehow, but found out that the valve stem had ripped the tube, and realized that this tube had been installed and removed about 10x more than any other tube I'd ever used - all in the course of around 4 hours.  

As the test in going on, you watch the data set develop on the screen in front of you.  It's a very lively experience, fraught with anxiety and joy and relief and it's really just exciting.  Of course you don't have much time to watch because you have to prep the next wheel to go out for a test.  The thing in the world it's most close to is probably being backstage at a fashion show, except there's no hot models walking around half butt naked.  It would be cooler if there were a lot of hot models walking around half butt naked.  

The tunnel itself was designed and built in-house.  The bigger Aerodyn tunnel next door (same corporate parent) is where NASCAR teams do their testing (a Nationwide Cup car team was there today), but the A2 tunnel can test anything from bikes to cars, too.  The fans have a staggering 640 horsepower between the 4 of them, but in testing bikes at 30mph, you only use around a quarter of that.  A Computrainer is the guts of the wheel contact part.  The tunnel is cool, but the sensors and software are the business.  Their IT guy is smart.  They've incorporated a new measurement for steering axis torque since our last visit, which we'll be talking about in more detail, but boy did the results not make me a liar for all the times I've said 34s are invisible to cross winds. 

This endeavor is FAR from cheap, but it's necessary.  For example, we get asked about the 34 front 52 rear "mullet" combo all the time, and though we were quite laughably accused of pulling answers out of our butts on what we say about that (we've actually researched it quite a lot), we suffered the expense of testing it because until you really know, you really don't know.  The quote at the top says it all.  Today was a really interesting day.