Words and images by: Kraig Willett
Excerpts of this article originally appeared in Triathlete magazine in March of 2008. What appears below is the original, unedited article.
Most folks like to go fast on two wheels. Going faster than one has ever gone before feels great and the manufacturing community is more than happy to develop new products that can help pro’s and weekend warriors alike reach new limits in the speed department. It’s no secret that bicycle equipment manufacturers have been selling speed for decades.
In the past, the primary selling feature of new cycling products was “lighter”. More recently, the focus has shifted towards products that have improved aerodynamics. It’s relatively easy to measure whether your new frame is 100 grams lighter than your old frame, but nowadays, it’s not so easy to measure whether or not your new frame is aerodynamically superior to your old frame. Wind tunnels are expensive, and other aerodynamic measurement tools require patience and some moderate technical skill in order to tease out relatively large differences. The purpose of this little blurb is not to tell you which brand or specific product you should buy, but to identify which categories/topics provide the best value in terms of improving your speed (all else being equal) during your next bike split.
Cycling speed is determined by the interaction of the supply side (how much power the rider can generate) and the demand side (equipment related things such as mass, aerodynamics, tire rolling resistance, drivetrain efficiency). Different magnitudes of benefit can be achieved in each of these areas for different time and dollar investments – it is the ratio of “increased speed“ to “dollars spent” that will be qualitatively laid out below. By focusing our efforts, time, and dollars on the most critical factors and equipment choices, we can make smart choices in the search for speed.
The retro-grouches, techno-phobes, and the destroyers of hope of the world, might say the best way to go faster on the bike is to train more. Well, yes, if one is untrained, any training will definitely help… And training smart helps even more! It’s also quite possible that technology can speed up the training learning curve and improve motivation. A key thing to remember, though, with any training product/method, is that one should be open minded and willing to reconsider or reevaluate their current training process. Some products/services that might help your training include:
· Individualized Coaching ($1000-$3000/yr)
· HR monitor ($50-$400)
· Training log (software or journal based) ($5 - $150)
· Powermeter ($800-$3500)
· Cycle-computer ($30-$100)
The benefits of these products/services can affect both the amount of time one spends training, and also how many watts one puts out during their next event. As a final note, it’s entirely possible that one has already maxed out the supply side without any of these gadgets, so more gains would not be possible. In this case, the best value would be getting the same supply with less time commitment.
Improving the engine is a biggie when it comes to going faster, but it too comes at a cost! How much is one’s “free” time really worth? Of all the things in this article, the only topic that could be argued as “free speed” would come from the supply side – it could be argued that by spending money on one of the products/services above you could have an increase in speed (or maintain your speed) and do it on fewer total training hours – higher valued hours that you could be spending with your family, or working on your run!
At 30 kph over a course with zero net elevation gain, roughly 75% of the forces one must overcome are due to aerodynamics. Of those aerodynamic forces, roughly 80% of that force is due to the big floppy human sitting in the saddle, and 20% is due to the bike. This means that the way you sit on the bike accounts for approximately 60% of the total forces you must overcome while riding, while the entire bike is about 15% of the total force. Positioning seems like low hanging fruit!
There are different approaches to finding the fastest position for triathlon – most of the time when one pays to be professionally fit, one is buying a method based on angles, empirical formulas, body part measurements, etc... The method used by the fitter may or may not lead one to a position that is faster – it’s a risk one takes. From a theoretical perspective, the fastest position for triathlon will be one that allows the individual to produce the desired power over the duration of the effort, maintains one’s ability to process fuel, not adversely affect one’s ability to run afterward, while minimizing aerodynamic resistance. This is a slightly different perspective than what more than likely makes for the fastest position for a pure time trial.
This positioning process might take some time to allow the body to adapt to a significantly altered position. The expectation that one will be optimally positioned during a one hour fit-session, or even a one-hour wind tunnel session is not a reasonable one. It might get you in the ballpark, but it is up to the individual to continue to pay attention to what is going on with their performance, primarily from a supply side perspective. It is worth noting that the time it takes to get your position truly dialed can be reduced by using tools/methodologies that measure both the power produced by the athlete, and the aerodynamics of the position. Depending on where one starts with their position, it’s possible to see really significant improvements in bike speed splits.
Some variables to play around with when searching for the fastest position should include:
· Reach (distance from saddle tip to end of aero bar extensions)
· Drop (vertical distance from top of saddle to elbow pads)
· elbow width
· forearm angle
· head position
Evaluating the differences between available pieces of equipment is a little bit easier than the positioning topic, since improved speed is purely a function of the product itself. In other words, one can bolt on the new part and theoretically go faster.
Theoretically? It’s shocking but true: bike legs in triathlons are not conducted in wind tunnels or in the lab, so sometimes when one bolts on new equipment, one doesn’t immediately go faster on their first ride. This lack of increased speed straight out of the box may be due to many different things such as environmental factors (wind, air density, etc…), or possibly, the new widget really isn’t any faster than what is currently on the bike.
The good news, though, is that most of the new aerodynamic equipment out there really is faster both in the tunnel/lab and also out on the road than “standard” equipment of old. Below you will find some brief notes regarding many of the products available for upgrading your bike equipment in the quest for improved speed.
Aero Helmet ($130-$200)
Aero helmets can perform differently on individuals, but without a doubt, they work from an aerodynamic perspective when compared to a standard vented road helmet. When picking out a helmet, pick the smallest size that you can comfortably get on your head. Longer tailed helmets aren’t necessarily any better, and typically, fewer vents will improve aerodynamics. Some folks do talk about overheating issues, so that’s something to consider.
Aerodynamic wheels are probably the most wind tunnel tested product over the past 10 years – there have even been scientific journal articles written on the topic of wheels! In a general way, wheels exhibit improved aerodynamics as the rim depth increases, spoke counts decrease, and spoke/hub shape is refined. Improved speed from wheels can also be impacted by lower mass, but this plays a much smaller role. When upgrading wheels, consider aerodynamics first, and overall mass second – a really nice combination would be a rear disc with a tunnel tested and proven front wheel. The qualitative ratings below are generated relative to a set of 32 spoked, 20mm deep rimmed wheels.
Frame/fork ($2000-$3500) and fork alone ($300-$500)
There’s nothing like a new frame and fork to bump up the motivation to ride. Quantifying the aerodynamic benefits of a frame is bit tricky, though. There are several different approaches to testing frames in a wind tunnel; one way is to test the frame/bike without a rider. This approach reduces variability introduced by floppy humans pedaling, but does not introduce any rider/bike interaction effects that might take place. Some manufacturers have taken up the practice of using static “dummies” to sit in the saddle while developing the latest and greatest new frames in the wind tunnel. This approach appears to be a step in the right direction; however, it still misses out on the pedaling motion and introduces other setup challenges.
While independently wind tunnel testing forks in isolation several years ago, it was noted that a good predictor of aerodynamic performance was to measure the width and depth of the fork legs. The more streamlined the critical members (i.e, the fork legs), the better the fork performed. Frames may globally follow this rule of thumb, but due to the multiple elements in a frame it doesn’t appear to be quite this simple. Furthermore, some frames perform better than others depending on the wind conditions. The qualitative ratings below are all estimated relative to a round tubed frame and non-aero fork.
One of the better values out there in terms of improved speed for the buck comes from your lowly, neglected tires. Tires will give you a double whammy, since the right tire can simultaneously improve wheel aerodynamics and rolling resistance. Often times, the tire one puts on their expensive upgraded wheels will wipe out the majority of the aerodynamic gains. Pay attention to your tires, and begin asking manufacturers/shops tire performance related questions. The qualitative ratings below are all estimated relative to a mid ranged OEM tire.
Clothing (loose vs tight) ($80-150)
Another great performance value can be had by paying attention to your clothing. Avoid baggy jerseys that flap in the wind. The jersey doesn’t need to be super oversized, have the jersey unzipped, or look like a burlap sack to set the stage for an aerodynamic train wreck. It’s easy enough to find a skin-tight garment that doesn’t flap in the breeze, so why not take care of this low hanging fruit? The qualitative ratings below are estimated relative to a classical fitting road jersey.
Aero Bars ($200-$500)
The primary benefit of aero bars is that they allow one to assume a more aerodynamic position. However, there are still some nice features out there on products that can help one cheat the wind. Frontal area is a nice proxy for estimating how well aero bars will perform in the tunnel, but it should be noted that frontal area really only tells half the story. The shape of aero bars, in particular the base bar, can also play a role in their aerodynamics.
While aerodynamics are important, it’s probably best to make your aero bar selection based on how well they will adjust to where you’d like to ride and/or experiment with riding. Fully integrated bars (bars that include the stem and the base bar as one piece) make these adjustments more difficult, but can be very slippery aerodynamically. The qualitative ratings below are estimated relative to a round tubed cowhorn base bar and a set of clip-ons from the early 90’s.
Ceramic Bearings ($150)
There’s been a bit of noise about ceramic bearings in hubs, bottom brackets, and derailleur pulleys of late. While it’s true that there are potential losses in these bearing components, the magnitude of these losses are buried within the 2-3% of overall drivetrain/bearing losses. Furthermore, bearing losses are more than just a function of the geometry and material of the bearings; it’s likely that the specifications to which the mating hub components have been machined or the installation process is more important. If you are looking for a way to get a slight speed increase prior to your “A” race, make sure the chain and cassette are relatively new. The qualitative ratings below for ceramics are estimated relative to standard cartridge bearing assemblies.
Based on comparing typical speed improvements and typical costs for each category of equipment, it is possible to determine a “value” score. This score, scaled from 1 to 100 (100 being the best value) should help prioritize future upgrade purchase decisions and allow for relative comparisons between product categories investigated.
Another way to help folks visualize the relationship between pricing and performance improvements is to construct a plot like the one below. It should be noted that both the table above, and the plot below are for comparative purposes only and have been scaled to help visualization and to create spread between product categories. The relative ordering has been preserved, but magnitudes may be distorted.
(click to enlarge)
It’s possible to buy speed. It’s also possible to train more effectively. Folks are continually searching for that competitive edge to win their next race, or simply lay down a personal best at a given event. The good news is that most of the demand side related products out there are an improvement over what was available prior to the aero focused product development of recent years. Hopefully, this article has helped identify concepts and product categories that can have the largest impact on your next bike split, and also has made you aware of some really great speed values. Have fun striving to reach your goals with the help of your new equipment this year!
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