BE AERO: I can remember racing time trials with drop style handlebars for years; my back would be screaming by the end of most TTs over 30-minutes. Then came aerobars and it was a whole new deal, not only for comfort, but for speed as well. Optimizing your position on aerobars is important for multisport athletes; just putting them on your bike and hoping for "free" speed is not enough. I see too many riders struggle with aerobar positions that aren't even close. Most of the aerobar positions I see at the races are set too long (over-extended), and too high.

Speed gains with an optimal aerobar position are significant, well worth the additional weight. Faster riders will gain proportionally more speed than slower riders, especially on the flats and downhills as benefits of reducing wind resistance increase in proportion to speed. At climbing speeds there's little or no advantage.

First I'll assume that your seat position is correct. Keep in mind that to slide your seat forward (or back) to change the distance to your aerobars is not an acceptable way to change the reach. You need to choose the right length or adjustable aerobars from the outset.

In choosing the type of aerobars, the kind of handlebar they'll mount on makes a difference. You'll need the correct type of aerobar to clamp on to either your drop bars, or bullhorn style bars. With drop bars you'll need an aerobar that mounts as low as possible so that your forearms rest right at the level of the tops of the bars. With bullhorn style TT bars, the aerobars you choose should have some extra height above the point where they clamp on, as a properly fitted bullhorn bar and stem combination should be significantly lower than drop style road bars.

Some models of aerobars have an adjustment for length, some don't. On drop bars you should choose an aerobar length where your hand position does not go more than about an inch beyond the brake levers. ITU pros (and draft legal junior racers) are limited to drop style bars with an aerobar that doesn't go beyond the furthest forward point of their brake levers. This is for safety reasons, but in fact gives a pretty good position when the reach to drop bar's position is optimal.

There are a few one-piece combination bullhorn/aerobar units available. With these the length can't be adjusted. More importantly your effective stem length might be set as well, so do your research carefully before buying to make sure they'll work with your current frame's top tube length.

Clip on aerobars that don't have a length adjustment typically come in several lengths. There's usually a guide on the box where you measure your forearm length for proper fit. Keep in mind that if your handlebar position is correct most of your forearm length is already factored-in, so I find few if any riders need the longest length. The small and medium sizes work for the majority of riders.

You've chosen the aerobars and are mounting them on your bike. Here is how they should fit:

• From a side view, your forearms should be level. Some early wind tunnel tests found forearms tilted up gave a lower drag coefficient, but level forearms give a much better balance and feel on the bike with excellent low drag numbers.
• Looking from the side, the inner angle between your forearm and upper arm should be 90 to 110 degrees. If this angle is greater than 110 degrees, the reach to your aerobar is too long and potentially gives low back problems and less leverage/power. If the angle is less than 90 degrees, you're too close. This usually means your bike's top tube or stem length is too short. In rare cases your aerobar may be too short.
• Set your elbow width with comfort as first priority. Narrow elbows are not always faster; hands together out front with elbows apart in a "V" shape will direct airflow around body and can be just as fast as elbows close/forearms parallel.

The closer to horizontal your back is, the lower your aerodynamic drag coefficient will be - a good thing. But for many athletes their lower back/hamstring flexibility limits how low they can go so setting an aerobar position one can comfortably maintain for the race's duration is crucial. I'm typically on my aerobars for 95% of the race. I only come off the aerobars standing for quick accelerations, braking, very sharp corners, and steep (small chainring), or stand-up type climbs. An Ironman distance athlete holding the position for hours may need a higher position then sprint distance specialist.

Finally, use the aerobars every chance you get in training; the more you use them the more comfortable it is to maintain the position on race day!