Ep. 10 Sponsor - BiSaddle ShapeShifter EXT BikeFit Edition

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Size Cycle vs. Fit Bike

Chris Balser, otherwise known as the bicycle fit guru, joined the podcast this week to discuss the ongoing debate on how to define the dynamic units pictured in most fitting images found on the web, social media or in shops around the world.  Chris is clearly a specialist on this because he already composed an article on his blog a few years ago titled, “Fit Bike? or Size Cycle?”   He conducted trials testing the fits between a fit bike and a trainer and measured client outcomes.  Through this podcast, Chris aims to answer the question of whether the dynamic fitting bikes on the market currently are better for actual bike fitting or does the true value reside in using it as a pre-bike purchase sizing mechanism.

Interestingly enough, in Ep. 10 Chris goes well beyond the discussion of what it should be called and expertly explains his experience with bike fitting technology and it’s the accuracy when fitting the unique human body to a bicycle.

The podcast is broken down into 3 sections where Chris discusses the following:

1.) The Accuracy of 3D analysis systems

2.) Size Cycle or Fit Bike

3.) The bike fitting placebo effect

THE DIVE: Ep. 10 Topics

  • Journey Into Bike Fitting
  • “I may not have it, but there’s always a solution to a problem.”

3D Systems Review

  • 3D marker accuracy, the attempt to change the world of bike fitting
  • Morphology’s impact on 3D marker accuracy
  • What are the dots actually showing you?
  • The detail of the fit is in the person
  • The abandonment of symmetry protocols
  • Attempting to create symmetry may create more problems than it solves
  • Other reasons of why L/R power may not be even–a look at body symmetry
  • The dots (3d motion capture) don’t tell you enough about the human body

Size Cycle or Fit Bike?

  • There is a tremendous amount of variability between what constitutes getting fit on a fit bike and riding outside.”
  • Testing the fit bike on his own clients vs. the trainer
  • “The trainer does not represent real life, it represents a trainer.”
  • The fit bike fit tendencies
  • Stabilizers in bike fitting–the impact of a sizing stem
  • The nervous system response to a fit bike
  • Center of gravity on a fit bike
  • Size Cycle is necessary for new bike purchasing
  • Chris’ protocol for finding proper stem length
  • The accuracy of transferring measurements from fit bike to bicycle
  • Imperfections in the bicycle and the impact
  • Fit bike position vs. actual bike position

The Bike Fitting Placebo

  • If the fitter says the fit is great, is the fit great?
  • “My knee still hurts” but your bike fit was “perfect”
  • Fitting is trial and error
  • “Test everything against what you think is accurate”
  • “Anything better than shitty is great”
  • Bike shop fit focus
  • Independent fitters should provide a great product and should have exceptional outcomes
  • The value of your service should match client expectations
  • Always have a genuine interest in the client and be honest about your limitations

I don’t think you can be fit as well on a bicycle as you can on a fit bike. There’s this holy grail of position that occurs when you get positioned on a fit bike and it’s impossible to replicate.  I think it’s impossible to replicate because the nervous system isn’t acting the same. You can relax more on a fit bike than a regular bicycle.

If you’ve even been fit on a fit bike, you know the moment when you’re like, Oh my god, that’s perfect.  It happens and it’s powerful. It really is the holy grail of positions. The problem is it’s not real.  A fit bike is not a bicycle.


Chris Balser

Bicycle Fit Guru

Chris Balser started his bike fitting journey in the late 80s by tinkering with the fit of kids he was coaching on the Pedro’s New England Junior Mountain Biking Team.  After moving to Pittsburgh in the early 90s to pursue a doctoral degree in psychiatric and alcohol epidemiology, racing elite mountain bikes and opening his own bike shop, Steel Mill Cycles, Chris was dealing with chronic knee pain.  A specialist at the University of Pittsburgh diagnosed him with severe chrondomalica and informed him that he would never run or race again.

Instead of quitting, Chris decided to utilize the University of Pittsburgh database to delve into the research of the body, his injury and began a lifelong learning process in becoming a great bike fitter.  In fact, Chris still researches the human condition regularly and is currently researching how a human functions more like a primate on the bike.  

He utilized Fit Kit at his shop in Pittsburgh and eventually moved to Minneapolis where he started the fit program for Erik’s Bike Shop.  After working there for about 10 years, Chris could not endorse the new program adopted by the shop and he left to create his independent fitting business Bicycle Fit Guru in 2008.  

Chris went on to invest and study new technology in bike fitting.  He developed a 27-marker, 860-operator integrated 3d/ EMG program for cycling assessment protocol in 2012 and developed a biofeedback protocol to reduce counterproductive pedaling technique.  He also developed a symmetry protocol and a fit bike that would simulate “real world” conditions for BTS Bioengineering in Italy.   

Chris’s extensive research, consultation, and development of technology led him to discover that those tools of bike fitting do not render the accuracy required to match the individual unique human condition as well as the function of the body on a bike in “real world” conditions.  

Through this process, he also became a yoga instructor, continues to ride his bike, fits over 800 cyclists per year, fits cyclists from around the country to solve issues and spends time with his wife and two kids in Minnesota.  To learn more about Chris’ bike fitting and life journey, see his personal bio.

To learn more about Chris’s bike fitting services or to contact him for a bike fitting, please see his website below:



  1. Mircea Andrei Ghinea

    Well, this was a good one… Thank you! Regards, Mircea

  2. Howard Freedman

    Great interview. Chris always has interesting things to say. There’s lots of good information for fitters to use in their private practice. Looking forward to a follow-up.

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