You love to compete in the local time trials and you’ve done well on your road bike equipped with bolt-on aero bars. But you’ve been watching the pros during the TTs in all the recent stage races on their fancy (and expensive) aerodynamic time trial bikes. And you’re wondering: Should I get one of those or continue to use my road bike?
The most important aspect of aerodynamics is rider position, not the aero qualities of the bike. Teardrop-shaped down tubes and seatposts make a difference, but it isn’t significant compared to your furiously pumping legs and wind-catching chest.
As a result, a road bike fitted with aero bars and set up so the rider is in an optimum position is nearly as good as a dedicated time trial machine. In fact, in the past, before all riders always rode dedicated TT bikes, it wasn’t uncommon for a rider on a regular bike set up for a time trial to beat riders on TT bikes. It’s the motor, the position and whether your legs are good on race day that are the most important factors.
Time trial bikes do have one advantage: They’re designed to make getting an aero position easier. They usually have steeper seat-tube angles and a handlebar much lower than the saddle. But if you move the saddle forward on your road bike and use a stem that allows you to lower the bar, you can come pretty close. This week and next, we’ll provide tips on how to get the most out of your road bike while time trialing.
Maximize Your TT Speed with These Tips
Lower the handlebar and install aero bars. Wind tunnel testing shows that every rider’s optimum aerodynamic position is a bit different. Some riders are more aero with their elbows nearly touching. Others get lower drag numbers when their elbows are wider, allowing the wind to flow between their arms. But during years of testing many riders, a standard model that works for most cyclists has emerged.
It begins with your back parallel to the ground when your arms are on the aerobar armrests. Also, your upper arms should project forward from your shoulders at about a 30-degree angle. Achieve this measurement with a shorter or longer stem or (for some aero bar models) by moving the armrests. Finally, adjust the width of the armrests so your upper arms are in line with your body, not angled outward where they’ll widen your profile and catch more wind.
Move the saddle forward about 1 cm. Because you’ll be bent lower, you need to move your saddle forward slightly from your normal road position. This opens the angle formed by your hips and chest. The closer your back gets to horizontal, the more forward your seat position must become (unless you increase your flexibility a lot!). Time trial bikes generally have steeper seat tube angles to facilitate this forward saddle position.
Refine your position. You probably don’t have access to a wind tunnel but you can look carefully at your position using a mirror or by recording a video of your position. Check from the front and sides. You want to see a compact shape with a flat back and no protruding elbows or knees.
Most riders can produce more power for a given heart rate in a more upright position. Climbers sit up and hold the bar top because the position feels more powerful to them — and at climbing’s slow speeds they don’t have to worry about wind drag.
At time trialing speeds, however, most of the resistance you feel is from the air, so you need to get as low and aero as possible. But for every rider there’s a point where getting lower compromises power output so much that the aero advantage is negated.
You can approximate this boundary by time trialing on a flat, windless road at a steady speed and heart rate. Sit up a bit for a mile, scrunch lower the next mile. See what your speed and heart rate do.
If you have a power meter you can be even more exact. This experimentation will help you arrive at your “sweet spot” where power and aerodynamics are in perfect balance.
Don’t forget: We’ll finish this 2-part series next week with more tips on maximizing your road bike – and your ability to ride it – as a TT machine.