Most Common Fitting Misconceptions

A version of this article was originally
published in Triathlete Magazine

After surfing the net and talking to many friends, I’ve heard many different opinions about what is right and what is wrong in regards to bike fitting. What are some of the most common positioning misconceptions that you hear and what are the real answers?

Tobias , CA

Dear Tobias,

The most common misperceptions that I hear are the generalizations – the ones that treat every rider the same. Some of the most common that I hear, and their real answers, are below:

Misconception: “I read on a web site that because I ride a 56cm road bike, I should ride a 56cm TT bike.”

Reality: A triathlon position and road position have more differences than similarities and there is no correlation between the sizing of your road bike and that of a properly fit triathlon bike. The only way to know for sure what will work for you is to build a triathlon specific position and then use the information from this fitting to find frames/bikes that match your triathlon position well.

Misconception: “Riders between 5’7” and 5’11” should ride with 9-12cm of drop from their saddle to the top of their handlebars.”

Reality: While some riders in that height range will ride with this amount of drop, there is no way to accurately generalize about how high or low someone’s handlebars should be to maximize comfort and efficiency. Body proportions, range of motion, core stability/strength, injuries and aerodynamics must all be taken into account to determine what works optimally for your body as an individual.

Misconception: “To achieve proper saddle position, raise the seat until your heel just touches the pedal at the bottom of the pedal stroke.”

Reality: Optimal saddle position cannot be accurately determined from a formula, by measuring the rider’s inseam, or any other general rules of thumb. Optimally, you want a saddle position that allows for full leg extension without hyper-extension, is within your range of motion, helps you maintain a stable pelvis, and encourages proper pedaling technique and optimal muscle recruitment. This is most accurately achieved through observation by a trained eye in conjunction with rider awareness.

Misconception: “Based on my body measurements, Web site/bike shop ‘X’ says I should ride a 52cm.”

Reality #1: Body proportions alone just tell a small piece of the positioning story and often can be as misleading as they are helpful. The variables that should be taken into account when building your riding position and determining frame size include an awareness of your riding habits and any injuries, your body’s individual range of motion and strength capabilities, your biomechanical alignment and finally your riding posture and technique. Body proportions are only about 1/5 of this equation, and arguably one of the least reliable in regards to achieving a final position or determining bike size. A comprehensive fitting will look at all these variables and then will help you not only find out what size bike you really need, but will also narrow down which brands and models will work optimally.

Reality #2: Sizes between brands vary immensely as one brand’s 52cm might have a 74 degree seat angle and 54cm top tube and another might have a 73 degree seat tube angle and a 53cm top tube. These two bikes will fit distinctly different. You cannot just look at the size of a bike to get an accurate idea of how it fits. You need to look at each dimension individually and how it relates to the other dimensions that determine fit.

Misconception: “I see a lot of pro athletes on (insert bike brand/model here) and many of my friends who own (insert bike brand/model here) say they like it so I figure that it should work well for me too.”

Reality: Choosing a new bike based on what has worked well for your friends or what a pro athlete (who is often paid to use that product) rides is akin to choosing a running shoe based on what someone else runs in. What really matters is what will work for you as an individual. This means that a bike should first and foremost fit you well and some brands are almost sure to fit you better than others. Beyond fit, a bike’s ride characteristics (stiffness, compliance, handling…) should also match your needs and wants well and each of us is unique in these regards too.

The presiding problem with each of these misconceptions is that they generalize too much and do not pertain to the individual’s needs enough. The most important thing to be aware of, in regards to bicycle fitting is that each of us is unique. From flexibility, to body proportions, training time, biomechanics and our riding history, we each have our own capabilities and constraints that influence what will work best for us. Your unique and individual aspects need to be understood and taken into account in regards to your riding position, as well as the products you use, if you are to maximize their effectiveness.

Good luck and ride hard!


Originally published December 2005/Copyright © 2005

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