Bike Fit & Positioning:
The Key to Comfort and Speed!

Bike fit and positioning are two related but different topics. They have a big impact on many issues including:

• comfort
• aerodynamics
• power output
• muscle recruitment

The focus over the past few years has been on bike fit; however fit is just the first half of the puzzle. Let's look at the difference between fit and positioning and what you can do to improve your position. Step One: Fit
Many triathletes are riding bikes that don't fit them. Bike fit is determined primarily by two measurements, the seat tube length of your frame (frame size) and the top tube length of your frame. Most people consider only the seat tube length (“I ride a 56cm frame”) without considering the fact that 56cm frames from different companies may fit differently due to different top tube lengths. Based on torso and arm measurements in addition to inseam, we can determine both your “ideal” top tube and seat tube length. With this information you can find a bike that fits you. This is where positioning comes into the picture. A bike that fits simply means you have the potential to achieve a comfortable and efficient position on it.

Step Two: Positioning
Positioning is more complicated due to the number of inter-related factors. In this sense it is like a puzzle whose pieces include: saddle height, saddle fore-aft, overall extension, arm rest drop, arm rest width, and aerobar angle. The adjustment of these factors is governed by their effect on the angles at your knee, hip, shoulder and elbow. We look for a particular range for each of these angles. One of the biggest issues for triathletes is being too stretched out when using the aerobars. A good rule of thumb is that you should be able to fit not much more than your fist between your knee and your elbow when they are at their closest point. If you are too stretched out you can correct this in several ways.

1. Your stem length (also affects weight distribution)
2. Your aerobar extension (also affects your armrest position)
3. Your saddle fore-aft (also affects your hip angle). If you are riding a road bike, moving your saddle forward or using a forward seatpost may be the best option as it will also open up your hip angle.