Knowing that setting up a triathlon or time-trial bicycle involves the manipulation of many variables that interact with each other, how should you set up your bike on your own?
The place to start is with the saddle adjustments. Getting the proper saddle height and setback is critical for good, efficient power development. Generally a triathlon bike saddle should be slightly lower than a road bike saddle, about 3 to 5 millimeters, to compensate for the pelvic rotation which raises the hip joint.
Next, work on getting the proper saddle setback to achieve a position that places the knee close to even with the pedal spindle (as measured from the bony protrusion on the front outside of your knee). This measurement will change slightly as you raise and lower your handlebars, so it is good to continue to check it while setting up the front of the bike.
The handlebar should be low enough that you have a nice flat torso, but not so low that you are uncomfortable or lose significant power development. We say a flat torso and not back, since some people have a rounded shape to their back even when their torso is flat.
Lowering the front of your bike while using a device that measures power on the bicycle (such as a Computrainer) can help you determine when your position is too low, as you will see a dramatic loss in power development.
Fine-tuning the front end of the bike is the last detail in positioning, and it is dependent upon how low the torso is. If you have a very low position, you do not need to have your arms as narrow as if you sit up higher.
With a low position, the arms should be at a width that places them in front of the thighs, as they also allow for rounded shoulders. With a higher position the arms should be as narrow as comfortably possible. It is also important that the forearms be on a relatively flat plane and not point significantly up or down.
When seeking professional help on fitting a triathlon or time trial bicycle properly you should expect to pay around $150 for a good fitting that measures your power, efficiency and comfort.
Expect to pay a few hundred dollars to have your drag measured. This may seem expensive, but when you consider that a good fitting in a triathlon position should take at least a couple of hours and involve a large number of costly measuring devices, the price is understandable.
And considering that the riders position can save many minutes of time in even a 40K event, it is a bargain compared to the cost of additional aero bike equipment that can save only a few seconds.
Christopher Kautz, M.A. and Eric R. Pardyjak, M.S. are co-founders of PK Racing Technologies. Kautz currently serves as tactical director of marketing for Nimble Bicycle Co.
Pardyjak, whose background is in aerodynamics and mechanical engineering, holds a turbulence research position at the National Laboratory at Los Alamos, N.M. and is finishing a Ph.D. in fluid mechanics at Arizona State University. Both are category 2 cyclists. They can be reached at www.pkracing.net.