The “One Number Obsession Fallacy Phenomenon”

Every once in a while Seven Cycles works with a customer that has a hyper-focus on one specific element of frame geometry or design—it could be just about any part of the frame.  We call this the “One Number Obsession Fallacy Phenomenon”—or O.N.O.F.F. for short.  Yes, I know that “phenomenon” isn’t spelled with an ‘f’ but that’s part of the joke…

I estimate that 99.8% of Seven’s customers are very open to design input and recommendations from Seven and from our retailers.  The other 0.2% have some strong ideas on bike design.  We love working with both types of customers.  It’s always fun to design bikes with customers that are up for anything—we get to work from scratch and with our entire palette of options.  Equally, the few customers that have strong design or engineering ideas are also great to work with because they tend to think—over-think—about all the design details; this keeps us on our toes and allows us to have a deeper level of conversation about bikes.

And then, we have one more type of customer-designer that doesn’t even register on the percentage scale:  only a couple times each year—the ONOFF customer.  Obviously, the ONOFF customer is a rare breed.  We can discern the One-Number-Obsessive person by a few telltale traits:

• A willingness to forgo logic in order to ensure the singular obsession.
  
• On or off:  the acronym ONOFF works well as a double meaning because the person typically views the number as a digital outcome:  yes or no.  On or off.  There is no grey-area; no middle ground; no middle way.  It’s either perfect or wrong.
  
• A myopic focus on a non-critical design element.
  
• Minimal change.  Part of what qualifies as an ONOFF is that the required parameter is not much different than what Seven recommends in the first place.  A few millimeters, a half degree, a certain hue of color…
  
• The outcome is a Pyrrhic victory for the customer.  Look it up. 
  

A real-world example of a “popular” ONOFF is a myopic attachment to a specific chain stay length.  The most common reasons cited for a predetermined chain stay length is to increase climbing traction or to make the bike's drive train stiffer.  The chain stay length logic tends to go something like this:

The rider begins, “The best bike I ever owned has a 40.5 cm chain stay length.  That bike’s stiffness is perfect so I want to make sure my Seven has the same length stays.”

“Alright”, we might say. 

Then the rider slips in, “By the way, I’m doing a self-supported cross-country ride later this year; so I want panniers, and big tires, and…”

“No problem.  No conflict there.”  That’s Seven.

Shortening the chain stay by 0.3cm makes the drive train stiffer, right?  Well, sure; and that’s kind of like asking to make the top tube shorter so that the frame will be lighter.  [We have had that request.  Honestly.]  While the statement is true, it’s barely true, and—more important—the tradeoff made by the rider is not worth it; it’s a petite Pyrrhic victory… 

I certainly understand how a cyclist might get into this conundrum—why a rider might think that the favorite bike was that way because of a specific element, but it’s simply not the case.  Fortunately, or unfortunately—depending on your perspective—no one number or factor is singularly important.  A bike design is, of course, thousands of factors playing together to create an outcome.  The bike is a complex system:  frame, components, rider, and cycling environment.  Even the bicycle frame itself is a sophisticated system of geometry, tube set, material choices, tolerances, rider influence, and craft.

Isolating one small detail on a pedestal, and then messing with every other detail to counterbalance the isolation, is just a really bad idea. 

For Example

If, in the case of a mountain bike, the hypothetical rider wants a better climbing bike, and the customer believes that’s accomplished through shorter chain stays, well then, we’re limiting our design options.  Yes, one of the elements to review is certainly chain stay length—and it is only one element.  To clarify, here are a few of the ways Seven approaches the “better climbing” design parameter:

• Improve rear wheel traction.  Many people think that “better climbing” and “improved traction” are one in the same.  However, we could have the best traction ever, and the bike could still climb poorly.  The traction design challenge and the better climbing design challenge are not one in the same—they simply require concurrent design thinking.
  
• Optimize balance between the wheels.  Weight distribution between the wheels shifts when climbing, descending, or navigating single-track.  In which circumstances is handling more important to the rider?  How do we optimize for all types of terrain?
  
• Optimize rider center of gravity.  This is an element of “Balance between wheels”, although it’s not interchangeable.  Gravity center and wheel relationship are three dimensional.
  
• Drive train stiffness.  In general, the stiffer the drive train, the better the climbing capability of the bike.  However, drive train stiffness in isolation can actually hinder climbing.  I’ll explain why in another post.
  
• Vertical compliance.  This is a very important element for optimizing a frame’s climbing ability—and often overlooked in frame design.  It’s analogous to how a good suspension bike can climb better than a hard tail—the suspension can help keep the rear wheel in contact with the ground.
  
• Component choice:  tire choice—width, tread profile, brand, tire pressure.  Wheel specification:  wheel stiffness and rim width are a couple examples.
  
• Terrain and environment:  typical climbing conditions; types of climbs—short and steep or fire road?  Dirt type:  clay or loose gravel?
  
• Other design objectives:  at what else does the rider want the bike to excel?  In what ways will these expectations impact the bike’s climbing capabilities?
  
• Chain stay length.  There it is.  Bet you were waiting for it.  The idea that shorter is inherently better can get us in trouble.  I’ve seen many a mountain bike where the rear wheel was tucked too far forward so that the rider has to be so far forward on the bars, while climbing, that the bike becomes difficult to handle.  The outcome is a situation where poor handling outweighs the improved traction, and the bike climbs poorly.
  

These nine examples are just part of how Seven applies all aspects of bike design to improve climbing.  It may also be apparent that focusing too much on chain stay length as the climbing solution, can easily end up hindering the overall design of the bike. 

Oftentimes, the extent to which a rider holds onto the ONOFF view of the world, is the extent to which the bike will be less than what it could have been for that rider.  It’s great to obsess over bike design--that is part of Seven's job, afterall; it’s not so great to obsess over one specific number.  Bike design is all about factor balancing and systems thinking.