Buying an Aerodynamic Front Wheel

One of my closest friends is a very gifted road cyclist that races prominently and may be working towards a career as a pro. He recently wrote to me about purchasing an aerodynamic wheelset and asked me my opinion about the products available. Below is my response to him, slightly modified to be a more fitting blog entry.

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In regards to wheels, here's my synopsis of the available options.

Aero wheels can, for all intensive purposes, be divided into two categories: toroidal and non-toroidal. The toroidal cross-sectional shape, a special kind of bulge, is protected by a patent shared by Zipp and HED. Zipp in turn shares it with its Flashpoint subsidiary and SRAM affiliate, while HED produces rims for Bontrager. It's widely accepted now that the toroidal cross section is the most optimal shape for an aero wheel, and it basically operates by filling the low pressure gap formed by the air splashing around the leading edge of the tire. This generally leaves wheels like Mavic, Shimano, and Reynolds, which have a standard V-shape trailing edge, behind in terms of aero performance. Reynolds has made some strong claims about achieving comparable performance with their new rims, basically by making them extremely narrow, but there claims to my knowledge have not yet been independently affirmed, and to me would seem to only really apply to very low yaw angles (like when riding into a headwind). This high-performance at low yaw-angles could correspond to a loss of performance in cross-winds. Check out this image showing results from an independent lab comparing a wide range of wheels in the wind tunnel. 

Aero Wheel Drag Data circa 2007. Click to enlarge. 

For more information regarding cross-sectional shape and aerodynamic wheel performance, check out this article.

The venerated Zipp 404 clincher uses Zipp's 505 rim. Though it's 58mm depth puts it in the same range as the wheels yet to be discussed, its $945 retail price puts it in another, much higher price point


So if we look at toroidal wheels, we have Zipp, HED, Flashpoint, and SRAM. Zipp is the 'no-holds-barred-top-of-the-line performance' brand, but doesn't really (since 2007) offer a tangible performance benefit over HED or Flashpoint worth the markup. So we look at HED and Flashpoint. Both companies offer an excellent product and I know of innumerable tales of HED's excellent customer service. Given the comparable price points and performance, I would consider it a wash between these two. A review from testrider.com (now Peleton Magazine) is no longer available but spoke very favorably of the Flashpoint 60 wheelset. 

The Flash Point 60

And check out HED's website to read about their wheels, specifically the HED Jet 6 C2. HED's website is extremely informative and I love this page, Aerodynamics , where you can compare the aero performance of their wheels at different yaw angles (for readers not up to date on yaw angles, here's an example, although HED's website has an interactive yaw angle tool as well. 0 deg yaw would correspond, say, to riding directly into a headwind. Riding at, let's say, 25mph into a light cross wind would be 5 deg, stronger cross wind would result in 10 or 15 deg, etc...)

The HED Jet 6 C2

The SRAM wheels are slightly different. Whereas the HED Jet C2s are basically an aluminum clincher with a carbon fairing, the SRAM wheels are a carbon wheel with an aluminum rim affixed to it. I personally like the HED system, as, for me, there's a lot more ease of mind in case you hit a pothole, but the SRAM system could offer some performance advantages (like stiffness or vibration dampening) that carbon fiber is touted as having. Slowtwitch has a huge forum and aero wheels are often discussed. By looking them up I found nothing but good things about people's experiences with SRAM wheels. The basic synopsis is that they're heavier than HED, with lower quality but still quite nice bearings, hubs, and spokes. 

SRAM S60, also available in an attractive gray/black color scheme

Along with Flashpoint, SRAM wheels were reviewed favorably in all of the independent analyses that I found on-line (eg. the previously mentioned testrider.com reviewed them and were impressed). 

The toroidal shape of the SRAM S40

'Aero trumps weight' is a die-hard mantra of triathletes (especially considering our mostly flat or gentle courses at a constant tempo). Weight among wheels at comparable price points can still be a valid consideration, however. Whereas the front HED Jet 6 C2 comes in at 774g, and the front Flash Point 60 at 854g, the front wheel of the SRAM S60 runs 835g. This puts it well in the same range as the more expensive wheels, but almost 10% heavier than the HEDs. There are two perspectives on wheel weight. One contends that, since it is rotational, not translational, weight, a 60g reduction in wheel weight will mean a lot more than a 60g reduction in static frame weight. It could mean, some contend, that slight bit of extra energy to make the last wheel after a split or break in the race, or allow you the extra energy after an hour long crit to pull off the win in the final sprint. I wouldn't be able to tell you whether or not it's worth ~$200, though, to jump from the SRAM S60 to the HED Jet 6 C2 or FP60.


The opposing view on wheel weight, however, is that the weight of aerodynamic wheels is not a significant metric for consideration. Given the exponential nature of drag increasing with speed, the greater aerodynamics of a wheel made heavier by it's slippery shape more than compensates for the added mass. There's some very valid math to back it up, as well. Check out this editorial from Slowtwitch on the subject, Why Wheel Aerodynamics Can Outweigh Wheel Weight and Inertia.

Finally, regarding comparing the above options, the one reference I can make is to groupsets. SRAM wheels are like Rival- they offer pretty much the same performance as Red at a fraction of the cost, they're just heavier and by far the best value. HED is like Ultegra SL, which I consider to be the best combination of value and high-performance, and Zipp is like Record, which may be the very best but is also obscenely expensive.

If it were me, I would buy the SRAM S60 or S80 front wheel and keep my wheelcover over my Ksyrium Elite rear wheel. But I won't be penalized by the extra weight the way you may be.

The best option? Don't buy an aero wheel and instead buy a powertap hub on a handbuilt box rim wheel, like this $660 option from excelsports.com

A Powertap hub and monitor/computer

That would probably be of greater benefit to your cycling than any aero wheel (same for me), but it's not as sexy. 


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And there we have it. The synopsis regarding buying an aero front wheel concludes, rather abruptly, with the answer of 'don't' and instead buy a handbuilt wheel with a powertap hub. Should you already be training with power, or are disinterested in putting the effort into using a powermeter to its best effect, then by all means grab one of these excellent wheels. 


Quick Disclaimer:

1) It seems redundant to say, given that it's on a blog, but the above entry is just my opinion, 2) Any information or phenomena presented as facts are up to the reader to verify rather than blatantly accept as truth, 3) Prominent brands, like Bontrager, Easton, EDGE Composites, and Shimano, in addition to less well-known brands like Gray or Neuvation, aren't thoroughly considered purely due to my lack of familiarity with them, 4) Since he's a road cyclist, this entry is purely a consideration of appropriate aero wheels in the 50mm-60mm range of rim depth. These are all also the most versatile front wheel for the triathlete as well so the conversation is quite relevant to the time trial and triathlon cyclist.  I could greatly expand on many of the above subjects, and likely will in future entries, but will keep this entry as a synopsis for someone new to aero wheel purchasing. 

Triathlon Racing: The Importance of the Swim Leg

The importance of the swim portion of a triathlon is often characterized by the expression, "you can't win it on the swim, but you can lose it." Despite this, triathlon's most under-appreciated discipline has tactical and practical importance.

The inception of the Ironman triathlon is directly attributed to the result of a feud between the Waikiki Swim Club and the Mid-Pacific Road Runners Club, as pertaining to which athletes were more fit. The resulting competition, however, certainly doesn't favor the skillset of the former group of athletes. If we look at the times of professional triathletes in Ironman-distance racing, a typical winning time will likely include the following splits: a 52 minute swim, a 4:35 minute bike, and a 2:55 run. Of the resulting 8 hrs and 22 minutes of racing, swimming only comprises about 10% of the time involved. Yet, the strategic placement of the swim as the first event, and the inherent difficulty of moving through liquid as opposed to air, allocates greater importance to swimming than the numbers suggest. 

5 out of 8 matches believe you should've joined a Master's Swim Club

Another common expression among triathletes alludes to a collection of matches. "You have only so many matches to burn," it says, with the metaphorical matches representing hard efforts during the race. Use too many during the swim, and you could find yourself miserable and dejected on the run, even after a well-executed bike leg. Energy conservation thereby serves as the first pillar upon which the importance of swimming is built. Spiking your heart rate during the swim and unnecessarily depleting metabolic energy reserves is an excellent way to destroy a race. You can't have a stable house if you built it without a foundation, and you can't have a good bike-run if you spent twice-as-long as you should have swallowing half the river and exhausting your legs in a desperate attempt to reach T1. The very nature of swimming makes energy conservation difficult, however, as moving through a liquid medium, as opposed to air, provides all sorts of challenges. 

There are very few objects, save maybe an open cardboard box or a parachute, that are less hydrodynamic than a human. Though somewhat commendable on land, we fail miserably in the water. Arms and legs jut out from a central trunk and require a fairly complex motion to even approach efficient forward movement during a front-crawl stroke. Understanding your enemy is key, however, and the enemy is drag. Moving efficiently through the water is a two-pronged approach- one must seek to both eliminate resistive forces (for example, form drag and frictional drag) while maximizing propulsive forces (as in optimizing the pull phase of your stroke). For example, I address this dual-nature of the sport by thoughtfully completing specific drills in each workout aimed at refining my stroke (reducing drag) before beginning a hard interval workout (maximizing propulsion). I first set about learning to swim well by studying the act itself. I used Swimming Fastest, by Ernest Maglischo and highly recommend it to anyone who wishes to become a student of the sport. 

Faris was strong across all three disciplines in 2005, but an early lead in the swim set him on the path to victory. (photo courtesy of 3athlon.de)

So energy conservation may be the first pillar of swimming, but the wet-side of triathlon extends far beyond just going through the motions. For those who are or aspire to be competitive in the sport, swimming has many important tactical considerations as well. This is most evident in ITU-style racing, where making the lead swim pack can itself make or break your race. It's even been a powerful factor in Ironman racing, with Faris Al-Sultan's early break to his Ironman Hawaii victor in 2005 serving as a noteworthy example.  The resistance that water offers as opposed to air compounds the importance of how you position yourself relative to others (i.e. drafting) and makes getting dropped by a momentary surge both a constant threat and devastating thing to recover from. 

Coming out of the water in my first half-iron race in 2005. Sadly, this reminds me to do an entry on bonking during the run. 

There's also the role swimming plays in the overall race. I remember the final race, a sprint-distance, from my first season in the sport six years ago. I was 200 yards out from the run turnaround when a guy coming into it about my age shouted 'what age are you?' Stupidly, or perhaps brazenly, I replied truthfully- and immediately regretted it. Whereas the heavier build I had acquired lifting weights throughout high-school was good for opening pickle jars, it was nothing doing for my run splits. My new young friend, however, had the very thin look of an experienced runner.  The extra motivation led me to run a 5km time in the 18min range, faster, quite interestingly, than any standalone 5km effort throughout cross-country in high school, and I was able to finish ahead and win my age group. In meeting the young man, Elliot, after the race, I learned that his run split was equally faster than mine as my swim split was over his, letting a slightly faster bike on my part give me the deciding edge. Clearly all three sports played a role, but my strength in the swim allowed me to counter his strength in the run. 

Finally, the swim adds an element to triathlon that's difficult to qualify. The adventure of setting off in open water, be it a leap into chilly San Francisco Bay just off Alcatraz or a slow, reverent walk into the warm waters of Kona's Kailua Bay, the swim adds an element to triathlon that truly separates it from other endeavors (except, obviously, open water swimming). Much like a hike in a forest inhabited by grizzlies, even if nothing exciting happens, triathlon is more exciting for having open water swimming as part of the sport. It's also a truly unique skill, even an art form when one considers the required coordination. Standing on the beach adjusting my goggles, smelling the neoprene and looking out over the expanse of a lake or ocean and then wading into the still, cold water to warm-up for the race is one of the most beautiful and exciting moments in our sport. 

Oh, and there's one last thing. Swimming develops the upper body. For all of the degrading comments triathletes receive from runners and road cyclists, at least we don't have the upper bodies of pre-teen asian girls. 

Swimming....

...keeps triathletes looking like this (Pro-triathletes Michael and Amanda Lovato)....

.... and not like this (disgraced professional cyclist Michael Rasmussen)....

... or like this- the wraith like lead pack [though Ryan Hall (left) is a stud] at the Boston marathon.

Thai Trail Run: Khao Lak Lam-Ru National Park

Located just two minutes from the main strip of Khao Lak (which, actually, is pretty much all of Khao Lak) is the beautiful Khao Lak Lam-Ru National Park. The park, which contains a beautiful cliffside restaurant elevated into the jungle canopy overlooking the Andaman Sea, is solid rainforest pressed up against the tropical coastline.

On our first visit to the restaurant early in our time here in Thailand, I saw a trailhead sign near the restaurant indicating a 1.5km trail leading to a remote cove beach in the small park's interior. I'd looked forward to making the short trek ever since seeing it and finally the day came. After running laps around the same running track for the last three weeks, I was ready for some new scenery. My plan was to make the walk down to the beach with my wife, get all set up, and then run repeats of the trail section.

It was- for reasons very soon to be mentioned- not fully accomplished.

My wife Kendra along the trail

I was carrying the pack and after parking the car nearby, we headed down the path. I stopped about 10 feet in to grab the camera out of the side mesh pocket of my trusty backpack. Kendra continued walking and as I reached behind I maintained my gaze forward, distracted by the beautiful jungle scenery. The glint of sunlight off a spider web caught my eye and I followed it to the web's center where

holy-hell-there's-a-spider-the-size-of-my-face!

I just stood there and stared at it.

I suffer no ill will towards spiders, mind you, and have nothing near a phobia of anything save an irrational fear of sharks, but it was all I could do to just keep standing there staring at it. Kendra, further along the trail that quite inconveniently passes directly beneath the beast, senses I'm not behind her and turns around. She sees me just standing there staring and, immediately concerned, asks what wrong. Speechless, I just look down at her and then back at the spider. It would be indecent for me to repeat the words she then used.

Anyway, I overcame my initial surprise and managed to walk under the thing. We maintain a blog about our trip and I posted a picture there which I'll now link just in case the arachnophobic triathletes viewing this entry would prefer not to be involuntarily accosted by its image. It was, by our estimate, 8 inches in total length, with a body about 3 or 4inches long (very similar to or larger than the size of my thumb) and you can see it here . Turns out it's a Golden Web Orb Spider (turns out our 8in estimate was right on), and given its intimidating nature and position at the start of the trail, we would name it "The Gatekeeper."

Turns out, the Gatekeeper wasn't alone and we would encounter 5 more along the trail. In the interest of self-preservation, Kendra had me lead the length of trail to the beach so I had the privilege of discovering each of them. After the third, I just stopped telling her as it's simply easier to pass by them without knowing. It's safe to say that the plethora of giant spiders with a propensity to span the trail significantly dampened my previously unbridled enthusiasm to get in a trail run. Nevertheless, I was able to do laps of the sections that were proven safe. Here are some pictures along with some shots of the beautiful beach we found at the trail's end.  

A scenic, rocky viewpoint early on in the short hike

Running one of the 'safe' sections. When it comes to giant spiders, there are no safe sections.

Mitigating factors notwithstanding, the jungle was a beautiful, shady place to run.

The hike in, though short at just below a mile, had enough ups and downs and rugged patches to make reaching the beach feel like a pleasant reward. The warm water and small schools of fish made swimming around a pleasant way to cool off coming out of the humid jungle.

Playing with shadows on the powder-soft sand

Pictures from the running track in Thailand

Becoming Better: Skills Acquisition

My current favorite author is Atul Gawande. A general surgeon in Massachusetts, Gawande's writing style is both highly engaging- he frequently incorporates narratives of dramatic experiences accrued throughout his medical education- and quite authoritative- through a liberal citation of research studies. Two of the books he has authored that I have purchased, Better: A Surgeon's Notes on Performance, and, Complications: A Surgeon's Notes on an Imperfect Science, accompanied me to Thailand and I continue to learn from them as I re-read them.

In one part of Complications, Gawande depicts the necessity of tenacity and determination in regards to the successful acquisition of a skill; be it surgery, playing the violin, or professional athletics.  Gawande cites the conclusion of researchers who examined the disparity between top performers in many fields (mathematics, music, chess, etc...) and lesser performers. The difference did not lie in innate skill, but in, "the cumulative amount of deliberate practice they've had" [1]. The potential limit imposed by one's genetics upon their VO2 max is an oft-cited claim for prowess in triathlon, but maybe this is just a minor part of the story. Gawande cites the conclusion of cognitive psychologist K. Anders Ericsson when he writes that Ericcson notes, "that the most important way in which innate factors play a role may be in one's willingness to engage in sustained training" [1].

My experience with swimming certainly supports this line of thinking. Starting my freshman year of college, I began to swim in the university pool. I pursued swimming more intelligently than passionately, forcing myself to hop in the cold water and repeat stroke drills to improve my speed and efficiency. In the pool, I met Alan Jacob, a much better swimmer and very prolific cyclists (and now very good friend). Alan routinely swam daily and would clock +20 hours of riding each week regardless of the season.

When I first started swimming with Alan, I would finish maybe half of the set's 200-yard interval before he touched the wall. I remember once playing around with a warm-up by swimming with fins and thinking to myself how nice, but seemingly impossible, it would be to swim this quickly. Then Alan passed me in the adjacent lane. Swimming so slowly was frustrating.

But I kept with it. My weekly yardage held constant during the busy school year and, come summer break, I would build it up further. With each year of college, my average weekly yardage would increase and my interval splits would drop proportionally. Now, of course, it was the increase in yardage, guidance from Alan, and improved stroke mechanics that made me a better swimmer. But it was a continued willingness to go to the pool and repeatedly throw myself at a task wherein I improved very frustratingly slowly that facilitated these changes.

Leading the swim in a super-sprint triathlon held at the college during Sophomore year. I'm the closest swimmer and Alan is in the adjacent lane. I'd actually lead the race into T1, but only because Alan elected to wear bike shorts and had to keep pulling them up as he swam. He beat me by 5 minutes on the 12-mile bike leg anyway...

I remember one set Junior year. Alan and I were doing a workout we called the 400 medley, which was a continuous 400 consisting of '100 at moderate pace, 50 breast stroke, 100 build (slow to med to fast pace), 50 kick, then 100 build to a sprint. We were coming up to the wall just before the final 100 of the last 400 yard set. I was, for once, right alongside Alan. Feeling confident, I said, with a cocky edge to my voice, "I'm still here, Alan," while still staring at the wall of the pool inching closer. Alan turned his head ever so slightly and just gave me a look.

I got absolutely smoked on that last 100. Yet even though I lost the battle, in my mind I'd won the war. I was improving. In our workouts Senior year, Alan would come in slightly ahead of me on each interval just as often as we would glide into the wall together. But that improvement wasn't made from just the laps, the drill work , or the core workouts we did afterwards. It was made at 8:00 at night while staring out the window to pouring rain and a mile-long walk in the dark to the pool.

In one of our last swim workouts together after I graduated from college, I came across Alan doing some repeats with Kevin Wang, one of my school's best swimmers and now coach of the team (and the local Master's club that I swam with. Kevin was also a great source of guidance and inspiration). I hopped in and after a quick warm-up gave it a go. Kevin destroyed us both, but I glided into the wall in second place.

"Wow, you're really fast," Alan told me during the rest before the next set.

Elated at the compliment, I just smiled, dropped under the water, and kicked off the wall to start the next 200-yard interval.



*Gawande is a MacArthur Fellow, a general surgeon at the Brigham and Women's Hospital in Boston, a staff writer for The New York Times, and an assistant professor at Harvard Medical School and the Harvard School of Public Health. He's also, I've found, an excellent writer.

Sources:
[1]. Gawande, Atul. "Complications: A Surgeon's Notes on an Imperfect Science." p.20 . Picador Publishing, U.S.A. 2002

Today's Run

Upon arriving at the Step Ahead Khao Lak center, I was relieved to find a great place to run just 200 yards up the road. A widespread disregard for traffic safety makes running or riding along the road more dangerous than petting great white sharks and almost as dangerous as cycling in Texas.

The loop is approximately 1 kilometer long and circumnavigates a large pond (pictured above) in a D shape. The circuit is completely flat, but that just means I'll need to be creative. Various fartleks (or, speed play) runs will comprise a lion's share of my outings. Example farleks include surging the straight section (the backbone of the D), accelerating each time I round a corner (the path isn't curved, but segmented, so that would make for about 6 surges each lap), or varying my pace with the tempo of the song I'm listening to on my iPod Shuffle.

The sunrises and sunsets I catch from the little pond loop are extraordinary and I'll photograph and post them soon. Also, the loop appears to be a public park, and several locals walk laps each morning. I'm always greeted by warm smiles as I run the loop and do my best to exchange a cheery 'su wut dee krap,' or, 'hello' ( 'krap' in Thai is a word that makes a statement polite).

The Thai Diet

Sunset view over the Andaman sea from my new favorite restaurant

In his excellent book, Racing Weight: How to Get Lean for Peak Performance, Matt Fitzgerald outlines virtually everything the serious endurance athlete could care to know about optimizing body composition. Though I'll post a thorough review of the book later, it should suffice to say that I certainly recommend it if one needs to seriously address this issue in their training and racing.

Though the book has many benefits, one of them is assisting the reader in developing a proper diet strategy based off knowledge gleamed from diet journaling. Fitzgerald adds a quote to the effect of, "A measured quantity is a managed quantity," and while I'm not measuring my food on a scale a la Armstrong, I am addressing the fueling of my body with great focus.

In doing so, I have determined that, though I was eating very healthy foods, I was also eating more of these foods than was metabolically necessary. I was quite literally having too much of a good thing.

Enter the Thai diet.

For the 6 month period before I begin medical school in early September, my wife and I will be doing volunteer work in Khao Lak, Thailand. We are working with Step Ahead, a Christian organization that works towards local community development by assisting women and children at risk, teaching English and German, and many other special projects (such as developing sustainable agriculture in a nearby impoverished village, a project that I'm excited to be working on now). Should the urge strike you, you can read about our adventures on our trip's blog at yrockmovement.blogspot.com. 

Part of being in Thailand means I have the good fortune of having unprecedented access to Thai food. It's actually cheaper here to eat out than it is to make your own meal, as only 30 baht per dish makes each dining experience $1 USD. The portions, however, are certainly Thai-sized, and with meals just rolling around three times a day, I am probably eating in the neighborhood of 60% of the volume of my American diet. Combined with daily runs timed at sunrise and sunset, I have an excellent chance of making my way to my optimal race weight and a significant improvement in performance.

I'll measure my outcome by my performance in a penultimate running event, either the Phuket Marathon, half-marathon, or 10km on June 13th, in addition to measuring my body composition (lean mass and body fat % relative to my desired body weight). I'm excited to track this transition on these pages and look forward to faster running splits once I return to the States.

I can't say that I'm too excited to return, however, cause even though we spend quite a bit of time working, we have very easy access to paradise (and, as it turns out, vacant beach resort chairs near the beach). Please note the European-tourist in the background. It's like Kona in October over here- all of the Europeans are in Speedo-style swimsuits and none of them appear to have ever heard of skin cancer. I guess I'll add sunscreen advocacy among tourists to Step Ahead's agenda.