Time trial-specific, fully-aero bikes are fast—very fast. We all know that the $6,000 tricked-out rig with the $2,500 wheelset will save us minutes over a 40K course (not to mention the virtual eternity you stand to gain over 112 miles).
In fact, we have been keenly aware of the benefits of getting aero ever since the 1989 Tour de France, when American cycling star Greg Lemond used Scott clip-on bars on his stock Bottecchia TT bike and blazed down the Champs Elysee, riding into cycling history and revolutionizing the sport.
But what if you can't, or don't want to, take out a second mortgage on the house to purchase a top-shelf tri bike? Isn't there an easy—and inexpensive—way to get aero on your existing machine?
Of course a well-positioned set of aerobars will help you improve your bike splits. However, to get the most from your aerobars you must first address your drivetrain, or, in other words, your feet, legs and hips.
First let's get the geometry out of the way. A standard road bike will have a 73-degree seat-tube angle, compared to the more aggressive 75- to 78-degree seat-tube angles found on most tri-specific bikes.
Also, the top tube on a road bike will be a bit longer when compared to a tri bike. Finally, a road frame will be more stable, due to rider weight distribution, whereas aero bikes put more weight over the front axel, making the handling a bit more nimbly.
Due to these differences, a road frame is, in some ways, more efficient, particularly in the hills, since the rider is positioned to use the large leg muscles more evenly. Conversely, a tri bike places a greater demand on the quadriceps. However, for triathletes this forward position is beneficial since running causes greater stress on the hamstrings and glutes.
Therefore, if you are currently riding a road bike you can save your legs for the run by sliding your saddle forward to the point where (assuming you have the crank arms at three and nine o'clock) the kneecap of the forward leg is positioned directly over the toe of your shoe. Expect your saddle to be nearly all the way forward on the rails.
Keep in mind that for every centimeter your seat comes forward you will have to raise it one-half centimeter to maintain your original seat height. If your saddle height is correct you should have about a 30-degree bend in your knee at the bottom of each pedal stroke. If your hips rock from side to side when you pedal, your saddle is too high.
You can improve your cycling efficiency by adding a pair of clip-on aerobars (which bolt onto your existing base bar) to your machine. Before purchasing aerobars, however, check the diameter of your base bar: 26 mm used to be the standard clamp diameter, but larger stem clamps (that require a 31.8 mm stem and bar) are becoming more popular.
When you install aerobars, consider the following:
1. Your ears should be directly over your elbows. More specifically, the leading edge of your shoulders (deltoids) should be in line vertically with the backs of your elbows, creating a slightly greater than 90-degree elbow bend.
If you have a shorter torso and you are riding a standard-geometry road bike, the aerobars will likely be a bit too far forward for you to achieve this position. To solve this problem, install a shorter stem.
2. Ideally, you should rest your forearms on the aerobar pads just ahead of your elbows, on the wider, more muscular section of your forearms. The farther toward your wrists you shift the less comfortable you will be.
3. The aerobar handles should settle into the palms of your hands when your elbows and forearms are in the correct position. Thus, you will have two solid areas of contact with the bars: elbows and hands.
4. Lastly, your elbows should be in line with the width of your hips. Any narrower will make your position unstable and constrict your breathing. Any wider and you become a huge air scoop and compromise aerodynamics. Note, however, that if you are new to aerobars you may use a wider, more stable position for a few rides until you become accustomed to the position.
At race pace, roughly 75 percent of a rider's power is used to overcome aerodynamic drag. The above suggestions may not provide you with all of the benefits of a top tri bike, but they will help you achieve a faster and more efficient position on your current machine—without forcing you to drain your bank account in the process.