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Wrenchin' in the USA: The Chris Davidson diary 2008
Chris joins us again in 2008 to report on life on the road turning the wrench both in the road and MTB scene. Chris signs on with the new Team Type 1 squad for 2008; Chris has also worked for such teams as Navigators Insurance, TEAm Lipton, T-Mobile, Equipe Nurnberger and Mercury in the past, as well as neutral support programs with Shimano, Pedros and Trek.
As 2008 holds some new challenges for Chris, but some things will stay the same. One of those will be his informative diary contributions on Cyclingnews, where you'll often receive the inside scoop on all things tech and a look at life as a professional mechanic.
February 17, 2008
Learning about speed in the A2 wind tunnel
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Monday we headed back to the A2 tunnel with two athletes [one called in sick and could not make the session] and prepared for a day of dialling in the small details to make the athletes go faster. Mike Giraud and Dave Salazar at A2 have the most sophisticated setup to examine aerodynamic drag I have seen the US. They custom-built a bike platform with a Computrainer unit inside it to provide resistance for the rider while also measuring power output. The platform 'floats' above the floor on a unique jig sitting on top of the balance. They are able to project the data during the tests on the floor in front of the rider, such that he/she can see their power, heart rate, speed, etc. during the test runs. They also have three digital position cameras that record the rider's position while riding at speed. These proved to be fruitful as we were able to detect things such as increased body sway with narrowed forearm positions, when looking at the overhead cameras.
The day consisted of a series of runs at 30mph, where we recorded aerodynamic drag in grams while the rider pedaled at around 300 watts. The integrated digital camera and data collection system allowed us to scroll back through previous runs and compare views of the rider with the raw numbers. Small adjustments were the key, some times on the order of millimeters of bar height or width really would make a difference. Not every change led to the intuitive result, and this showed us the true power of the tunnel: repeated runs could be started about every five minutes if we were quick with our changes. Chris Jones started with low drag initially, but we were surprised that with less than 15 runs we were able to reduce this by more than ten percent – big results. Further runs/changes only served to produce higher drag, so we were confident that we had found a good position for Chris to spend some time with on the road.
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We left with some new data and ideas about going faster. 'Just getting lower' does not always work to reduce drag, the best aero position is rather specific to each rider. Hence, getting into the wind tunnel allowed us to get specific details right for each rider. The session was so valuable that TT1 has already discussed returning this facility in the next 90 days to work on some more riders and retest some that went today.
My work for the day was pretty simple once we got the bike installed on the jig. A number of times I was first to get back in the tunnel after each run, and asking the rider about the subjective feeling of the comfort and sustainability of the position changes became more important as the day went on. Not all positions were deemed 'sustainable'.
The end of the day came and the real glamour of my job set in. As the other team members headed to bed, I started the disassembly and packing of the TT bikes: in my hotel room. Not the ideal place, but much warmer than the hotel parking lot. Made it to bed just after midnight, with the alarm clock set for 3:50 and an early run to the Charlotte airport.
Next for me is a foray into the dirt as the 2008 MTB season starts for me at 24hours of Old Pueblo in Arizona. Then team camp for TeamType1 in Solvang at the end of the month. In not getting selected for the Tour of California and choosing the Tour of Langkawi instead, we had to fit our camp in between Langkawi and March's Tour of Taiwan. Right now, TT1 is still tied for the lead in Team GC at Langkawi, the boys are riding strong. Camp should be fun, as it will unite everyone on the team here in the States for the first time in 2008. I will have more details from there.
Until then, thanks for reading.
Chris Davidson
Photography
For a thumbnail gallery of these images, click here
Images by Glenn Kalnins / J.H. Williams Tool Group
- Chris Davidson consults with TeamType1 rider Chris Jones after the initial bike fitting .
- The initial changes to position involved manipulating the extension of the aerobars. Note the 'floating platform'.
- Chris Davidson cuts down the aero bar extensions to fit Chris Jones' bike.
- Chris Jones tries the new aero position before we make a run at speed.
- Chris Jones is happy with the adjustments and dons his aero helmet for the first run.
- After an initial run, Dave Salazar and Mike Giraud [A2] and Chris Davidson [TT1] discuss more subjective issues with Chris Jones' position.
- Forearms closer together, time for another run.
- Zipp's Vuka carbon aerobar setup adorns Chris Jones' Orbea Ordu TT bike.
- Mike Giraud of A2 monitors the controls. Three digital camera views on the left, Computrainer data in the middle and balance data [drag numbers] on the right.
- After a narrowing adjustment, Mike Giraud applies the 'human calipers' to Chris Jones to measure his foreman width.
- Adjust, measure, record, then fire up the fans for another run.
- Chris Jones' TeamType1 Orbea Ordu.
- Nathan Bartels of TeamType1 goes with more of a 'praying mantis' setup.
- The bike makes up less than 20% of the drag area due to its narrow profile.
- Nathan Bartels 'praying mantis' setup before run #18.
- Chris Jones spends some time between runs powering the Computrainer at ~250w to get a little training in and to keep warm. The tunnel will cool the rider off very effectively at 30mph and it you only pedal during the ~2 minutes for 'live' runs, you can get cold fast.
- An overzealous reporter from a local television station was determined to get footage in the wind tunnel WHILE IT WAS RUNNING, despite advice against it.
- Chris Jones chuckles a little as the TV crew has some trouble in the 30mph wind.
- Smoke stream work reinforced the observations that having the tail of the aero helmet fit closely with the shoulders and back enhances the clean transition of the wind flow over the helmet. Jones has the fit dialed.
- A mechanic's work is never done……. Time to pack up.
