25Seven

Cambridge Kickstand

Seven Cycles is located in southern New England—right outside of Cambridge, Massachusetts.  We’re lucky to be located in New England because we get so much snow.  Snow is, after all, nature’s kickstand.  In the winter, some call it a Cambridge Kickstand…

Freedom From Choice

I notice—and I’m sure a lot of others do, too—that as “bike fit” gains popularity, stock bike sizing options become more limited and homogenized.  On the one hand, I would think that if companies are promoting fit systems, these companies would also believe that it might be prudent to offer bikes in sizes that actually facilitate improved bike fit, rather than hinder the fitting process. 

Interestingly, overall, that’s not happening.  Over the past decade, more and more bike suppliers are offering fewer and fewer stock bike sizes.  Some major brands offer only six sizes of bike—bikes that cost more than $8,000.

Take a simple case of seat tube angle as an example of diminishing choices--although we could choose any frame geometry element and have the same outcome.  The seat tube angle is an important consideration in bike fitting because it determines the rider’s saddle position relative to the bottom bracket and crank set.  This relationship is one of the most fundamental foundations of bike fit, power output, injury prevention, comfort, and bike handling.  So, one might think that seat tube angle is fairly important. 

Well, let’s examine four of the best, and most popular, high-end stock road bikes in the US market.  Starting with the frame size that is closest to a 56.0cm top tube, the seat tube angles are:

Brace for Impact – Part III of V

An Interview with Ghostride Magazine

A while back I posted the first and second parts of a conversation with my friend—and coworker at Seven Cycles—Skunk.  He interviewed me for his world renow magazine Ghostride.  This part of the interview won’t make much sense without reading the first two installments—actually, even if you did read them it probably still won't make sense.  I won’t retell the story here.  You have to read the first parts, if you care.

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A Ground Clamp and a Safety Squint

An interview with Rob Vandermark by Skunk at Ghostride, Part III

To ease us into this installment, we were previously talking about the first Donut Race back in 1987 and some other racing type events, like "Get in the box"...

One Third of What You Want is Perfect

There’s an expression I learned early in my bike manufacturing days—probably in 1988:

“When you work with the Taiwanese you get one-third of what you asked for, one-third of what they think you asked for, and one-third of what they want to do.”

I first heard the words from Ron Andrews, back when he worked at Fat City Cycles.  At the time, I thought it was a humorous statement and that’s about all.  I had not worked with any Taiwanese companies yet, so my only reference point was the results I saw from companies that did source frames and parts from Taiwan.  And, it sure looked like Ron’s comment was true—sometimes the bikes seemed a bit off:  odd design choices, parts that had the appearance and feel of being designed by people that weren’t riders, durability issues, funky quality.

Well, now that I've done some work in Taiwan and China—mainly for other companies—I no longer find that comment humorous—although it still makes me smile.  I now find Ron’s statement to be true and fairly universal.  I’ve learned that the words hold a lot of wisdom.  In fact, his comment has been really helpful in my travels over the years—and not just in Asia.

Olin College Visit: Human Powered Vehicles – Part I

Last week Seven Cycles had a visit from some students of the Olin College of Engineering.  Actually, we had two visits from them. 

Olin College is an interesting school.  It is a new engineering school, very cutting edge, and employs a project-based curriculum.  I remember when the Olin Experiment began in the early naughts—before it became an accredited college a couple years ago.  It sounded very innovative back then and it has clearly kept its promise.  It’s the kind of school that I might have survived at—well, aside from the engineering requirements.

Last week’s visiting groups were from Olin’s Human Powered Vehicle Team.  It’s a student led organization with the goal of rethinking human powered transportation from the user’s perspective.  They are working on their 2009 HPV design—to be entered in the annual ASME HPV Challenge—and the Olin team is in the midst of evaluating their preliminary design. 

W. Edwards Deming and the Toyota Production System

A few days ago, Matt O’Keefe—Seven Cycles’ production manager—mentioned an online forum discussion about the merits of German versus Japanese motorcycles.  As one might imagine, it was a heated debate.  Somehow, the thread turned to W. Edwards Deming.

Chicken or the Egg

The commenter voiced the opinion—I’m paraphrasing—that Japanese quality and the Toyota Production System—TPS—would not exist, if not for W. Edwards Deming.  Basically, America is fundamentally responsible for Japan’s global leadership in high-quality manufacturing.  It’s an interesting comment; one with which many people would probably agree.

Matt brought up a good point that I had never really thought about before.  Would the TPS exist if not for Deming?  Was Deming the initial spark of TPS?

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.

Engineering: Buckling Limit of Frame Tubing

In the last post, I began to address Yoshi’s interest in understanding how Seven Cycles goes about determining bicycle frame tube diameter and tube wall thickness.

I’ve already discussed a bit about how we adjust ride characteristics; I then talked about how we think about ride characteristics.  Here I’ll address one of the most fundamental engineering parameters of any thin wall shell structure—like a bicycle frame tube, for example:  unstable shell bucking.

The concept of shell bucking is simple.  And the simplest example of unstable shell bucking is seen in the result of holding a soda can at both ends and twisting the ends in opposite directions—the can buckles.  It buckles because the can is an unstable shell.  In the case of a soda can, this instability is fine—in fact it’s a good feature—because the can engineers did not optimize the design around an open and empty can.  The can is designed to function when full.  When it’s full, it is not unstable.  When it’s empty, it’s very unstable.

Some Factors in Bicycle Frame Tube Engineering

Recently, Yoshi posted a statement and question on 25Seven regarding my post about tuning ride characteristics.  I’m paraphrasing his comment here:  

“I want to know how you made the average…  and the relation of diameter and the thickness?”

Yoshi’s questions are important and fundamental for frame builders.  Without giving away any Seven Cycles secrets, I can explain some of the interesting basics.

In the above mentioned post, I talked about how we adjust the ride characteristics on each individual frame.  Here’s I’ll provide an overview of how we think about ride characteristics—at least as relates to tubing.  In essence, I’m talking about why we bother with tailoring the ride characteristics and why it’s worth the bother.

Made In the U.S.A. vs. Made In China

I was interviewed today by an industry magazine writer. The writer is working on an interesting article that he probably doesn’t want me talking about in any detail—so I won’t.  What I can say is that Seven Cycles was asked to explain why US made bikes are preferable to Chinese made options.  A different interviewee had already defended the position that Chinese and Taiwanese made bikes are superior to US made bikes.

In some ways, this seems like a bit of a silly conversation, or comparison; I believe that most people would agree that US manufactured bike frames are of better quality than the best Chinese frames.  It does seem a bit difficult to argue with that.

Or is it?