2008-11-30

Cheat the wind, flatten the grass.

Last weekend was an exciting weekend in a few respects. With wind tunnel testing, bike fitting, and a cyclocross race in Easthampton, MA, I was certainly busy.

Last weekend, the MIT Cycling team was able to use the MIT Wright Brothers Wind Tunnel for many hours. Wind tunnels are few and far between, and getting time on them is neither cheap or easy, so we appreciated the 30-minute wind tunnel time slots as the unique opportunity they were. The test protocol was fairly straightfoward: with the wind tunnel running at 30 MPH, we mounted the bicycle (via modified quick-release skewers) on a force-sensitive platform, got a baseline drag reading, and got subsequent drag readings for a rider pedaling in different positions.

I used my wind tunnel time to tweak my position on my time trial bike. My time in the wind tunnel taught me a few things:
  • a 30 MPH, 30 degree F wind is quite cold for any period of time.
  • once you're already wearing a skinsuit and an aero helmet, body positioning makes the most substantial difference in aerodynamics. Being narrower and lower is ideal.
  • lowering the handlebars as much as is feasible is the easiest way to gain an aero advantage.
  • keeping your hands flat (by using flat or R/S-bend aero bars) is much more advantageous than keeping your hands raised (using ski-tip aero bars).

As I don't currently have a functional digital camera, we didn't get any pictures of me in the wind tunnel. Mike Garrett, a team mate, chronicled our time in the wind tunnel at http://www.triplepointstudios.com/MIT_Aero.html.

After our time in the wind tunnel, I was able to get a bicycle sizing by Todd of ttbikefit.com. Todd was nice enough to come all the way to MIT on a Saturday morning to assist our team with bicycle fitting. He has an effective system for consistently reviewing bicycle positioning. Todd will have you ride on a stationary bike trainer. He'll use a camcorder on a tripod mount to record your pedal stroke for a minute or two. Then, he'll use what amounts to a glorified image editing program to analyze your positioning on the bicycle. The most brilliant part of this system is the repeatability: since neither the trainer, your bike, or your camera moves between sessions, he can easily compare your position from one tweak to the next.

Todd seems to favor a very aggressively triathlon-biased aero position. He tries to put riders almost over the bottom bracket, with a 140 degree leg angle at the bottom of the pedal stroke. Compared to my road position, he put my saddle much lower and more forward than I would typically ride it. This allowed me to open my hip angle, and assume a lower position on the aero bars. Some experimentation with my road bikes taught me that this was NOT a good road position. Nevertheless, for triathlon positioning, Todd has a workable system and plenty of experience, and I would not hesitate contacting him if you have any triathlon-related questions.

As an important aside, I'm wondering just how useful this TT bike fitting and aero analysis was. Recently, the powers-that-be at USA Cycling decided to ban aero equipment, or specifically, not mass start legal equipment, for race categories below A in the collegiate race season; A-category racers will be able to use aero equipment only if it will be allowed at the National Championships. As I'll be starting the season racing in the B category, with a hopeful upgrade to A, I'm unsure that I'll be able to use a full aero position. (For details, see http://collegiatecycling.org/eccc/wiki/index.php?n=Events.FallMeeting2008.)

What is certain is that my Fuji Aloha CF2's frame, the same that Fuji uses to build their current SST road bike, is a very aerodynamic frame and would make a superb road bike. I have all the parts I need to make it into a great road racing bike, one that may be superior to my Specialized Roubaix, so that may be the way to go. The CF2 road bike, already Ivan Dominguez's choice, would be stiffer and more aerodynamic than the Roubaix, but likely heavier. I'll need a Jtek Shiftmate to allow me to use my spare Campagnolo Veloce shifters with an otherwise Dura-Ace equipped ride, and I wonder if the longer 175mm cranks will be more or less helpful in road races. We'll see.



With all of the thoughts about aerodynamics behind me, I went to the place where aerodynamics hardly matter at all: a cyclocross race. With some residual fitness from the summer and plenty of training this fall, I've been doing well at the local cyclocross races. What I lack in bicycle handling skills, I can compensate with power. So far, I've done reasonably well at the three cyclocross races I've done, well enough to convince me to go to the Collegiate Cyclocross National Championships in Kansas City this December. My race experience this weekend was far from ideal, due to a number of mechanical disasters. I'm just glad that this all happened before Nationals.

What happened, exactly? I was doing well in my race, moving up through the field and maintaining a top-20 position, when I got two simultaneous pinch flats after running over a concrete curb at speed. I rode half a lap on flat tired to the service area. The pit crew was nice enough to loan me a set of Zipp 404 clincher wheels, which served me well until my chain fell off of the chainrings at the major run-up of the course. While struggling to get the chain back on quickly, I managed to twist my derailleur backwards, ripping apart the derailleur cage and bending a derailleur hanger. I ran to the pit, where they gave me a spare bike (an Orbea) with flat pedals, which at least allowed me to finish the race a lap behind.

That was not the first time I had chain issues on the cross bike that I built myself. Using a triple crankset was a stupid idea, but that's all I had. With substantial modification, I was able to replace the three chainrings with a 39-tooth chainring and a chain guard. I hope that works better next weekend. I'd like to race the new configuration at least once before Nationals.

Cyclocross is fun, but I miss the warm weather that makes enjoyable road riding possible.

2008-11-11

Max Power!



Dieting and training are both going well. I've lost about five pounds since my last power-related posting of about a month ago, making me stronger. I also had an exceptional workout this morning, on account of my brand-new Kreitler 2.25" alloy roller drums. These are roughly 15-20% more resistive than my old 3" drums, so I'm able to push harder in a lower gear without spinning out. I can't wait to see how the new rollers push my training limits. I find that I'm most efficient around 88 RPM on the PowerCranks.

Most of the MIT Cycling team started with base training yesterday morning. I'm still in the middle of my cyclocross race season, so building the sustained power and maintaining my carefully calibrated routine of daily morning indoor workouts is my priority at the moment. Come January, I'll be doing longer roller workouts, perhaps double workouts to gain the correct number of hours, at a lower intensity. I just hope to avoid injury and burnout before the race season even begins!

Averaging over 400W today, this workout represents a massive gain of 14% of my power for an hour. Using a fan while riding, adjusting my saddle position to be higher and more forward, and eating and sleeping properly, all help greatly. My strength is still long-term power. Hopefully, some speed work closer to the start of the racing season will give me a sprint to back my staying power.

Today's morning weight: 176.6 lbs / 80.1 kg.

Time Wattage W/kg Comments
5s 1147 14.31 Moderate (Cat 4)
30s 620 7.74
1m 526 6.56 Fair (Cat 5)
5m* 429 5.35 Very Good (Cat 2)
10m* 414 5.17
30m* 408 5.09
60m* 403 5.03 Excellent (Cat 1)
120m 277 3.46

* denotes power record set today.

Today's "all-out" workout was quite difficult for me, and approaching my limit. My average heart rate was 165, and my max heart rate was 180. As an aside, while I was sitting at my desk doing some preparation for the ride, I saw my heart rate creep down to 45, which means that my resting heart rate has gotten even lower. I'll need to measure that sometime soon.

2008-11-02

Race Report: Northampton Cyclocross Weekend

This weekend, I participated in my fifth and sixth post-summer races. The MIT Cycling Team participated in the Northampton cyclocross races in western Massachusetts this weekend. With three car loads of people, we had a strong showing.

These were my second and third cyclocross races ever, the first being the Canton Cup race of two weeks ago. Cyclocross is a very different kind of racing than road or track. It requires more technical skills (though not as many as mountain biking), with many intermeditate intervals (like a road criterium). Sand pits, run-ups, and barricades pose obstacles that require one to get off the bicycle and run for a short period of time.

Both races this weekend were USCF Category 4 races, 40 minutes long, at 0830 on the course. Though at physically the same location, the organizers made substantial changes to the course between Saturday and Sunday.

I was less well prepared for Saturday's race. I was sick, did not get enough rest, and did not eat enough. Saturday's course, the more challenging of the two, offered one impossible and one very difficult run, a long sand pit with a corner, and a barricade. My early registration gave me a good starting position, but a lack of agression made me lose many places quickly. I faded with lack of food in the cold weather, becoming less and less able to handle the bike. I finished, painfully, in 34th place out of roughly 95 starters.

Including some cooldown: 11.02 miles in 52:56. 12.48 MPH avg, 30.27 MPH max. Avg HR 154, max HR 175. Avg power 193W, max power 1119W. 613 kJ of work.
Today's course was substantially easier. Many of the corners were replaced with long, straight sections. The sand pit was straight, and therefore, rideable. The runup was also rideable, though I had limited success doing so. I again made the mistake of not being aggressive enough off the start, and was bumped back pretty quickly. With more rest and more fuel, I stayed strong, working through the entire race. I finished a respectable 21st out of roughly 96 starters.

Race statistics: 10.21 miles in 44:21. 13.8 MPH avg, 26.9 MPH max. Avg HR 166, max HR 177. Avg power 266 W, max power 1048 W. 708 kJ of work.
What a great way to enjoy the cold weather.