10 Ways to Tell If Your Bike Fitter is Full of Shit.

By Tom Demerly.

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Bike fitting is big business. Having some version of “professional” bike fitting is the new standard for any bike sold above $1000.

How do you tell if your bike fitter knows what they’re doing? Are they a credible, trained, experienced fitter or just repeating buzzwords in a kind of bike fit “theater” learned in a weeklong clinic under the guise of years of experience fitting athletes during the evolution of bike fitting?

Here are ten checkpoints to assess the credibility of your bike fitter:

  1. Do They Ride? The Way You Do?

If a bike fitter knows what it’s like to be a beginner triathlete filled with anxiety and not even know what questions to ask they can help the newest beginner with solid recommendations. A good fitter knows the “beginner’s mind”.

At the opposite end of the experience scale, if your fitter knows what it’s like to sit on an uncomfortable saddle for six hours at Ironman- and can fix it– it’s easier for them to understand what you’re experiencing. If they have done it themselves, you’ve found a fitter you can relate to.

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“After their bike fits Dave and Enrique couldn’t help but wonder if there had been some confusion between their two appointments…”

When a bike fitter combines the “beginner’s mind” with elite level competitive experience balanced with formal training and tempered against learned judgment from doing thousands of bike fits, you have a master. And the less a new rider knows, the more the fitter must.

There are a few credible fitters who are not triathletes or bike racers but do know bike fit well. But they are the exception.

Having the practical experience of riding the way you do (beginner or expert) makes communication more effective. It also means your fitter had to apply what they’ve learned about bike fit to themselves. It teaches them critical thinking and hones their analytical skills. That makes them a better fitter.

There is a dark side to the super-athlete bike fitter though, see #10 below.

 

  1. Have They Been Trained in Multiple Methods? 

Beware of any shop or fitter than espouses a single fit methodology. If a shop tells you “We do Retül (or Guru, or FitKit, or Body Geometry, or FIST)” but uses no other system and is not familiar with any others, it’s worth learning how deep their understanding of bike fitting and positioning really is.

How long have they been fitting? Have you spoken to any other fit clients of theirs? What are their reviews?

Bike fit systems are only tools to make the fitting process easier, more theatric, and in some cases, to sell bikes.

Dan Empfield, inventor of the triathlon bike and of the Stack and Reach sizing convention teaches a F.I.S.T. bike fitting class in England.

Dan Empfield, inventor of the triathlon bike and of the Stack and Reach sizing convention teaches a F.I.S.T. bike fitting class in England.

The quality of the end product depends on the fitter, not the system. A fitter with experience across a number of systems has a more balanced understanding of the bike fit landscape and assesses your fit from a broader perspective. That likely means you’ll get a better bike fit. Beware of the one-trick pony and the Johnny-come-lately with the shiny new fit bike and laser levels.

 

  1. Do They Espouse One “Fit System” Over Another?

If a fitter uses only the cookie-cutter fitting system associated with the bike brand they sell, you may still get a good fit on that brand, but the fitter’s capabilities may be limited.

As with point #2 above, bike fitting systems are merely tools. All of them will produce a favorable result in the hands of a skilled fitter- but all of them rely on an experienced fitter.

Nice tools, but do they know their stuff?

Nice tools, but do they know their stuff?

When was the last time you asked your bike mechanic, “What kind of wrenches do you use?” As bike fitters become more experienced and capable the system they use becomes less relevant.

It’s the experience and skill of your fitter that matters, not the system they use.

 

  1. Do They Only Suggest New Saddles for Saddle Discomfort?

Saddle discomfort is a leading motive for bike fit, but if the only thing your fitter does to make you more comfortable is bolt different saddles on your bike or try to measure your “sit bones” to sell you the right saddle, then they are a good salesperson, but a poor bike fitter.

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A good fitter will take a holistic approach to saddle discomfort, addressing fit, position, saddle comfort habits, rider fitness and posture and the rider’s clothing to improve saddle comfort.

Bolting on new saddles is a great way to drive sales and usually the most logical approach to the customer, but it is a myopic view of what makes a person comfortable on a bike seat. Your fitter owes you more than a sales pitch on another magic saddle.

 

  1. Do They Claim To Be Able To Make You “More Aero”?

A great way to tell if a fitter is a hack is if they claim to be able to make you more aero without using wind tunnel testing or computational fluid dynamics.

A bike fitter can use empirical, data-driven checks to verify joint angles. They can take specific measurements of frame dimensions and geometry. They can take quantifiable measurements of your body and make mathematical comparisons to determine relevant ratios for bike fit.

A bike fitter cannot do this for aerodynamics. If your bike fitter claims to be able to make you more aerodynamic on your bike they are guessing, and lying.

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Air is 784 times less dense than water, and it is nearly impossible to predict the behavior of water swirling around your finger. Guessing how air will swirl around a pedaling rider at speed in different wind conditions is impossible without empirical analysis.

I know- I’ve been that guy. I spent over ten years telling clients I would get them “more aero” by lowering their handlebars and making them “more aggressive” until a wise man who happened to have a PhD in aerodynamics told me to “stop embarrassing yourself” by trying to guess at aerodynamics.

I’ve been privileged to wind tunnel test with two bike brands and one independent engineering laboratory in three different wind tunnels over 25 years, on the bike and in the control room. I’ve learned that no one can guess what small changes will make a rider faster over the entire length of a triathlon bike leg. And remember, the goal is to get faster, not just “more aero”, and while those two things are closely related, they are not entirely the same– especially for new riders with comfort issues.

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“Jim wondered about riding 112 miles at Lake Placid like this after his bike fit was over.”

Firstly, no bike fitter without a wind tunnel or computational fluid dynamic analytics can guess at the behavior of the boundary layer of air surrounding your body across the entire performance envelope.

Secondly, even if they could, the constantly changing variables of speed, terrain, wind yaw angle and rider posture would make that snapshot in time a very fleeting case study.

Thirdly, while rider aerodynamic drag is the most significant force to overcome in cycling even at moderate speeds, wind tunnel positioning concepts were developed in testing at very high speeds, usually over 25 MPH. British professional triathlon coach Russell Cox discovered the median bike speed for the Men’s 40-44 age category at Ironman Florida, one of the fastest courses in the U.S., was only 17.5 MPH. At these sub-25 MPH speeds there are more opportunities for your fitter to improve your bike split through things that they can actually test for, as opposed to things they are guessing at for speeds you don’t even ride at.

The narrative “Let’s lower your bars to get you more aggressive…” is a valid way to tell if a bike fitter is regurgitating empty rhetoric from YouTube, a triathlon forum, or a three-day fit clinic.

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Faster Bike Shop in Scottsdale, Arizona was the first and is likely the only bike retailer in the U.S. with actual wind tunnel test facilities.

If a fitter tries to critique your aerodynamics challenge them by asking, “Can we measure my drag coefficient before and after any changes?” You’ll likely get the sideways puppy stare or a litany of qualifying excuses. Don’t fall for it. There is only one bike retailer in the United States with a wind tunnel, Faster in Tempe, Arizona. If you aren’t there, then your fitter is guessing.

 

  1. Are They Trying to make you “Straight”?

There is a sub-segment of bike fitting and positioning that tries to enforce symmetry on the human form. The only symmetrical human is Mona Lisa. The rest of us are crooked.

It’s simple to use lasers and shims to try to make a person “straight”, but it may create further skeletal misalignment since our skeletons are usually not straight and symmetrical, especially as we age and accumulate injuries.

The craft of the experienced fitter is to find a functional balance between moderating asymmetries that could contribute to discomfort, or even an injury, and facilitating them. There is likely a “sweet spot” between facilitation and adaptation that provides the optimal benefit to each unique rider. This sweet spot is different for a new triathlete than a person doing their 10th Ironman.

If a bike fitter’s singular goal is to “get you straight” you should tell them to get bent.

 

  1. Do They Acknowledge Their Limitations?

Many bike fitters try to- or claim to be able to- do too much.

A retail bike fitter should be able to recommend a new bike model, frame size name and geometry that fits you optimally for the type of cycling you want to do. They can then adjust that bike for an optimal basic position, often using different handlebar stems, aerobars and other size-specific components to achieve the best result. Then, they can use any number of analytical tools to verify the results against commonly known bike fit standards.

That’s all.

Bike fitters can’t make you comfortable or “fix” you. They can’t add additional fitness or make you less overweight. They can’t produce the perfect saddle that feels right to you. You still have to train, lose weight if you are overweight and get acclimated to sitting on a bike seat. Those things don’t happen in a two-hour bike fit.

Unless the bike fitter in your store has a formal University level credential in anatomy, physical therapy, medicine or exercise physiology that should be their boundary, and they should respect their customers by working within their boundaries.

Beware of the bike fitter who tries to do too much without the degree to back it up. If a bike fitter learns a customer is suffering from a sports injury they are correct to refer them to a qualified physical therapist. Some licensed physical therapists now have formal instruction in bike fitting too, and you (or your health insurance) will pay extra for that, but it is worth it.

If your bike shop bike fitter tries to play physical therapist, limp out of there.

 

  1. How Long Have They Been Doing Bike Fits? 

Ten years ago it was still easy to sell a bike with a quick test ride. Now customers are smart enough to demand a more empirical, data supported process to selecting and adjusting the right bike. As a result there has been an explosion in the number of new “bike fitters” in the last ten years.

Not all of the new bike fitters are good.

Many new bike fitters are adequate and recognize their capabilities- and limitations- but many are also quick-talking hucksters who can sling the lingo and the laser beams to appear credible.

Ask your bike fitter questions about their training, their experience, their own cycling background and their limitations. A fitter who claims to be able to do everything has big shoes to fill.

 

  1. Are They Willing to Recommend Equipment They Don’t Sell?

It’s a good sign if a bike fitter occasionally “walks” a customer by telling them he has nothing in his store to fit them. That suggests their first motive is to get the customer on the right bike, not just get a bike out the door.

A specialty bike shop will stock a well-planned assortment of bikes that have subtly different fit characteristics. Some work well for larger, heavier riders, some for smaller riders, some for long torso cyclists, others for short torso cyclists.

When Triathlon Hall of Famer and inventor of the triathlon bike, Dan Empfield, invented the “Stack and Reach” table for comparing bike dimensions he created a kind of Rosetta Stone for bike fitters to make meaningful comparisons of different bikes and their dimensions. This leveled the playing field and decoded cryptic bike brand size names that have little to do with actual bike dimensions. Empfield’s accounting of bike dimensions gave bike fitters one of their most valuable tools since the tape measure, and also held fitters accountable for being honest.

 

  1. Are They Good Listeners? 

A good bike fitter conducts an interview with his customers, listening to their experiences, their goals and what they are thinking very carefully. This leads to more questions from the bike fitter. In fact, a good bike fitter often asks the customer more questions than the customer asks them when selecting a new bike.

The best bike fitters listen carefully to position their clients optimally on a continuum between facilitation and adaptation. Facilitating a client means the fitter exclusively listens to the client and does what they say makes them comfortable. Adapting a client means the fitter applies known principles of bike fitting without input from the rider and says, “This is right, get used to it.” The best bike fitters know how to listen to their clients to find the optimal balance between these extremes.

Some bike fitters try to be know-it-alls or local heroes. They try to mold each client into a specific posture or fit model, and they have little space left in their effusive knowledge of all things bike fit, cycling and triathlon related to learn anything from a lowly client. If you can’t get your bike fitter to listen to you, let them talk to the hand.

Craig Turner, founder of Nytro, one of the first triathlon shops in the world, is also one of the best listeners and bike fitters in the industry.

Craig Turner, founder of Nytro, one of the first triathlon shops in the world, is also one of the best listeners and bike fitters in the industry.

I once listened to Craig Turner, founder of Nytro in Encinitas, California, work with a bike customer. I was surprised by how little Craig said, how much he listened, and how he restated the key points the customer made back to them. It was clear that Turner was a careful and analytical interviewer, asking the right questions and leaving space for complete answers. When he was done with the interview he had the expertise to make learned and supportable recommendations. It was like listening to an expert attorney advise a client.

 

 

About The Author:

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While Tom Demerly can be full of shit he has been fitting bicycles since 1984 and performed well over 5,000 bike fittings including Olympic athletes Sheila Taormina and Olympian, National Champion and Tour de France rider Frankie Andreu. More importantly, Demerly has fit thousands of first time triathletes and only a few of them still have numb crotches.

 

 

 

 

 

 

 

 

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12 comments
  1. William Perreault said:

    Good stuff Tom.

  2. Excellent article here, as was the last article on local bike shops and their evolution! Great job Tom!

  3. Joseph said:

    Fantastic writing that simply puts it out there. As a PhD student in occupational therapy and married to a PhD student in Physical Therapy we constantly get referrals for injuries and anatomical differences where bike fits have not been corrected. I am not an expert at all in bike fits, but am willing to do what it takes to learn more and help to match the most proper fit to the individuals with different medical or anatomical needs. Thank you for the article.

  4. Great read! & I enjoy the sense of humor you have about yourself!

  5. 3D Bike Fit said:

    I think #5 is not entirely accurate. A lot of my clients will get an aero advantage out off there bike fit.
    I agree that changes are not quantifiable with a wind tunnel or Alphamantis, though it quite easy for most age group triathletes to be able to reduce aero drag by being fitted to a position that allows them to drop there head out of the wind, while still being biomechanicly correct.
    Great article, thanks for sharing.

  6. Ashton said:

    When I read the article’s title my first thought was great, another pompous PhD picking on the rack and file fitters out there who know their limitations and are genuinely trying to do a good job. The first thing I did was read the “about the author” page so I could confirm my suspensions. To my surprise the Mr. Demerly has a backgound that made me realize I should jump back and carefully read his piece. He has stated things I’ve been saying for years and this article should be included as the first page of any handout at any ‘fit school”. I am seriously considering paintning a few quotes from this high on the walls of my fit studio. Well said!

    • Wow- Ashton, thank you very much for your comments and especially for taking the time to read. Appreciated Sir. -Tom D.

  7. Ashton said:

    I’ve shared this with several friends in the industry and all have been impressed. Thank you for writing this.

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