Wednesday, March 15, 2017

Tunnel Fun

And so I've returned from A2 with some new insight and some slightly alleviated fears, along with one or two issues to work out. There is much to discuss but unfortunately not nearly as much that I can share currently (for a couple of very different reasons) so I apologize in advance.

The first thing I have to lament is that before leaving home I decided it was time to cut off my Peter Sagan - like locks. My hope is that it did not have a Samson-like effect...

Just a picture of the first leg shave of the year...

I drove down to Rock Hill on Thursday morning to do some pre-testing on the track. These numbers would be very helpful in validation since we don't actually ride in a wind tunnel and there is always some fear that what we find "inside" doesn't translate as well to the real world. There is more to the story about testing on Thursday, but it's not for me to expand upon at this time... let's just say it was a learning experience and that there are some very exciting things just around the corner for aero nerds.

Unfortunately my wife had to stay in TN and work (somebody has to be responsible while the rest of us play) which left me pretty much stuck around the hotel and surrounding area for the rest of the day. I took the opportunity to catch up on some of my recovery and basically just sat around watching Youtube video's and checking Slowtwitch every hour or so until bedtime. Unfortunately the one thing I couldn't do was fall asleep... so I tossed and turned on and off until I thought it was "reasonable" to get up and start trying to turn hotel instant coffee into something drinkable. I was not terribly successful, but it did tide me over until the real coffee was brought out to enjoy.

Friday I spent the majority of the morning just wrenching everything on the bike and making sure that I had not forgotten anything important for the tunnel visit. The drive from Rock Hill to A2 was estimated to be about an hour, so in my typical anxious fashion I left with plenty of time to arrive at my scheduled time of 12:30... I left around 9:30

Needless to say I had plenty of time to kill in Mooresville when I arrived. I explored a nearby Starbucks (the same as every other Starbucks I'm afraid) and then found a deserted (literally... I was there almost an hour and was the only person/vehicle/lifeform around) park that I walked the perimeter of in a thinly veiled attempt at passing the time.



When I arrived at A2 I was greeted by Heath and Geoff. We walked through a basic outline of what I wanted to test and then started unloading my car of all the junk I had brought with me. For the course of the weekend (including some training) I had a disc rear, ghetto disc (cover) front, 5 spoke, 3 spoke, training tubulars front and rear, 3 aero helmets (Aerohead, Spec TT, Kask Bambino) two aerobars (USE Tula and 3T Brezza Nano) and some skinsuits (team short sleeve castelli, Bodypaint, Nopinz Supersuit) along with two boxes of tools/spare parts and my drop bars. Whew... There was not much room in the car!

I tested at low yaw (0 and 2.5°) for all my runs, with the sweeps only on the controls, as I was looking for track data. I won't bore you all with every run and how many watts it changed (most of my changes were very small.) but I will mention a couple of things that ended up surprising me.

Run #1

- A trispoke, 5 spoke and (again, rigged up) front disc were all very close at 0 (and 2.5) with the disc slightly edging the other two out. What was very impressive was that my 5 spoke is a no-name Chinese knock off wheel, although one everyone who has looked at it has been impressed with. It also measured pretty narrow (~20mm at the rim) and with a 19mm Evo Pista tire on it one would assume it'd be pretty good at low yaw. Actually, at 0 yaw I would have expected the disc to possibly do the worst simply because it had a 23mm GP4ksII on it (compared to the 19mm Evo on the 5 spoke and a 20mm SuSo on the H3) I guess there is truly no replacement for depth.

- All the (fast) helmets I tested were pretty close, with the majority of them being within about 5w of each other (I tested the Specialized TT in small and medium, the aerohead - best, Poc Cerebral, Catlike long tail, and the Bambino, with the medium Spec TT being the worst and the small being second best) I expected a larger delta in the bambino honestly as I've heard it's often pretty bad. I went in expecting the Spec TT to be best, but it seems what we've been told about the aerohead being great is pretty true.

- UCI legal bars that are supposed to be fast (Tula's, 3T Nano's) were very, very close to one another. Within the margin of error I'd think. Maybe finding some narrower Tula's would be slightly faster still, or perhaps having better plugs (they had small cable holes in them) for the 3T's would have pushed it in favor of one or the other.

- Skinsuits were somewhat surprising. I truly expected my very nice Nopinz skinsuit to come out on top, but it was nearly 10 watts worse than my Body Paint, and around the same as my short sleeve Castelli (really a CX skinsuit w/pockets) and worse than the Cuore suit Heath let me borrow. In defense of the Nopinz, I didn't have two numbers pinned/glued to the other skinsuits, so it's possible that delta would be different on the road. Also of note is that my Supersuit was custom sized for me at 150ish lbs. At 165ish lbs it was a very, very tight squeeze. (it fit snug at lower weight) it was constricting in the core when bent over, and it's possible that had some effect. Long story short though, the off the shelf Body Paint suit is a slippery bit of kit.

- Lowering my position was not better for me. In fact my tallest bar height was best. That was very surprising, and I'd guess has a lot to do with how I hold my head (much higher) on the track.  Being higher helps open up the hip angle, so I'll take it. Likewise, raising my saddle a cm didn't negatively impact the CdA (which I also found surprising) but again, more comfort at the same speed is certainly something I'm interested in.

- Holding my hands higher was a pretty big jump for me. This was Heath's idea and it was a valuable one. Gripping the end of the extension with my pinkie and letting my hands "sit" on top was the second biggest change. Of course, this is VERY difficult to hold on the track... but I've got something in mind to help with that (and put the 3D printer to use!) already in the works.

All of our control runs were very close, and we spent the last bit of my time doing a long control run to see if there was any variation as I went along. All was very neat and close.

Final position/equipment

Later I checked in the data I had taken at the track and compared with the tunnel data. The two days lined up very nicely, which was a great bit of validation that what we had tested in the tunnel would actually translate to the real world.

Thanks very much to Heath and Geoff, they made the experience much better than just data collecting. Both guys you'd drink a beer with, not just listen to prattle off on a forum or an email. Also thanks to the folks at the Giordana Velodrome, who are always excellent folk to be around. And to the other genius out there who I won't name, a special thanks as well. I appreciate your insight more than you know.

Until next time, thanks for reading!

- Christopher Morelock

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