I've been very fortunate to have established a professional relationship with elite triathlete, cycling phenom and FitWerx 2 co-owner Dean Phillips. I have learned more from Dean about the application of all things aero and power oriented over the course of the past year or so than I have in the 12+ years that I have been involved in the sport of triathlon. I have benefited, and continue to benefit tremendously from Dean's technical advice and I'd like to pass on a few key points that I've picked up on as you begin gearing up (literally) for the 2008 triathlon and/or cycling season.
First off, believe it or not, aero wheel selection should constitute one of your secondary priorities when trying to figure out which gear you should invest in. The amount of drag generated by your rotating wheels is a relatively small fraction of the total drag you create when riding your bike.
Now don't get me wrong; you won't find me toeing the line of a major event, or any event for that matter, without my Zipp's, but the reality of the situation is this: The differences between the various aero wheels on the market are so slight that it really doesn't matter whether you're riding a set of 404s or 808s. In all actuality, for you smaller riders, the deeper wheel set might be more of a hindrance than benefit, especially when the cross winds really start to kick up.
Most people will find a wheel set like the Zipp 606 (404 front, 808 rear) to be about as good as it gets. For those of you who weigh in on the heavier side (160+ lbs) and can handle your bike well in cross winds (very important when you're screaming down a hill @ 30+ mph!), consider an 808 set up or even the Zipp 999 (808 front, rear disc).
See the following article by Zipp for a very informative discussion on the relationship between yaw angles, wheel design and drag.
Yes, I am a very big fan of Zipp wheels. I firmly believe that they are the best wheels on the market today, both from a quality and aerodynamic standpoint, and would ride them no matter if the company supported me or not.
Worried about wheel weight??? Don't be. There's a reason that you're going to start seeing more and more pros riding clincher wheels these days, regardless of the fact that they weigh up to 1lb. more than their carbon/tubular rim counterparts. The reason: Crr, otherwise known as the coefficient of rolling resistance.
I cannot stress to you enough how important it is to do your homework before you invest in a particular set of race tires. Believe it or not, your tire selection can prove to be MUCH more important than your wheel selection. Case in point: the wrong set of tires can cost you SIGNIFICANT amounts of time during a 40k, 90k or 180k TT. To put things in perspective, I rode a particular set of tubulars at last year's Eagleman 70.3 and based off of their Crr (when compared to the fastest tires on the market) I ADDED about 90 seconds to my 90k bike split! Shaving 90 sec. would have moved me up from 8th place overall to 5th place overall - just in front of Australian triathlete and 2007 IM Louisville champion Chris McDonald!
Please review the list of tires found HERE and their various Crrs/Crr related information. Take a close look at the number of watts required to move EACH tire (when mounted to a wheel). Double that number when you consider the fact that, unless you ride a uni-cycle, your bike has 2 wheels. You may very well be surprised to note that your current tire selection is costing you MINUTES in a long course race! The goal is to find the optimal balance between a tire that offers a low Crr and HIGH puncture resistance. Dean can help you with this critical decision.
As for the tubular vs. clincher debate, you'll notice that the top clinchers do in fact roll slightly faster than the top tubulars. However... Keep in mind that there are trade offs.
A tubular will pinch flat far less often than a clincher, so you're rolling the dice just a little more often when you race on clinchers (the way that I do). If I were a short course athlete, I wouldn't worry about puncture resistance and would opt for the fastest tire on the market, i.e. the Michelin Pro2Race lite or the new Pro3Race lite which has yet to be released.
For the long course athletes who ride clinchers, the Michelin Pro2Race (my tire choice) offers solid puncture protection, but will cost you a few watts. Tubular riders would do well on the Vittoria Corsa EVO CX or the Zipp Tangente. However, MAKE SURE that you have a Pro like Mark at Fitwerx 2 glue your tires on for you, as improperly mounted/glued tubulars can greatly increase your Crr and slow you down big time!
Rider position: I won't harp on this one. This is, by far, the most important factor when looking at the relationship between power output and drag. Your goal: Get as aero as possible (i.e. reduce drag) while maintaining or improving (for those of you on bikes that just don't fit!) power output. For the long course athletes in attendance, comfort while in the aero position in another key concern, so be prepared to sacrifice a bit of drag reduction for a higher degree of comfort and a lower back that's still in one piece after 90 - 180k of hard riding.
Bottom line: Spend the money and get yourself dialed in to your optimal aero position before you drop a cent on any gear (tires excluded given their relative low cost!).
Power Meter: Along with the majority of my client base, I am training and will be racing with a power meter this year. In 5 short weeks, I have seen unprecedented gains in my cycling fitness thanks to the use of my PowerTap 2.4 wireless. Simply put, if you're not using a power meter, you are at a major disadvantage during both training and racing.
Through field testing, a power meter allows you to clearly establish your precise training zones and, as a result, expedite your rate of physiological adaptation. By pinpointing critical sustainable power outputs such as your power at 100% of VO2max (i.e. average of max 6 min. effort power), power at high end of threshold (i.e. avg. of max 20 min. power) and MLSS power (avg. power for max 60 min. effort) you not only attain a blue print of your current aerobic profile, but can distinctly determine the EXACT efforts that you will need to work at in order to improve your cycling performances!
A power meter removes all of the variables from the training equation. No matter what the course grade, wind conditions, temperatures, road surface, tire Crr, etc. etc. you'll know exactly what you need to do every time you step out the door or onto your trainer.
In a race, you'll be able to pace yourself precisely to ensure that your effort remains steady throughout and that your legs are ready to roll as soon as you dismount and hit the run course (this statement takes into account the assumption that you've kept up with your run training!).
Outside of optimizing your TT position, training and racing with a PM is by far the best investment you can make. SRM, PowerTap and Ergomo are the brands to reach for.
Other considerations
Frame design: Yes, a properly designed areo frame will help to reduce total drag, but not nearly to the same degree that proper rider position will. Aero frames do help, but the time savings are pretty minimal. Priority should be placed upon how well YOUR body fits a particular frame, not the other way around. Once again, Dean can help here.
Aero helmet: Another relatively inexpensive means of reducing total drag. All things being equal, a good aero helmet will probably shave about as much time off your 40k TT as a set of aero wheels when yaw angles are really low (i.e. <2 degrees). As the yaw angle increases however, so do the benefits of your aero wheels.
In closing, if I could rank the importance of the issues mentioned above, and help you to prioritize what and where you should spend your money when it comes to racing and training cycling gear, it would be this:
1. Aero/TT Position
2. Tire selection
3. Power Meter
4. Aero Wheels
5. Aero Helmet
6. Aero Frame
Last but not least, always remember that the best gear/position in the world is close to useless if your engine isn't strong! I find it very "amusing" to watch people on $7,000 bikes traveling down the road at 13 or 14 mph. during big races. I think that they forgot somewhere along the way that fitness, above all else, reigns supreme!
-JRM
