23 May 2016

OTEC Will Keep You Going In Circles, But Not In The Way You Expected

Back when I was racing--and even when I wanted to stay in (or pretend that I was) in the same kind of shape I was when I was racing--one of the goals of training could be summed up in three letters:  RPM.

In other words, we believed that spinning at the highest cadences possible would make us go our fastest.  That meant riding, at least at first, in a lower gear and working up to higher gears.  The one who could spin the highest gear would win the race.

Now, of course, nobody is going to turn cranks with a 54X11 gear (which I actually had on my road bike for a time) at the same rate as, say, a 42X15.  But all of the trainers and training manuals told us that it was better to do 120 rpms on the latter (or a higher gear later in the season) than to mash the former.  If nothing else, it gives you a better cardio workout and is easier on your knees.

Apparently, there are some folks who don't agree.  Ever since the invention of the "safety" bicycle (two wheels of more or less equal size driven by sprockets and a chain), someone or another has tried to "improve" on circular pedaling motion.  Examples of such endeavors include the oval and elliptical chainrings that seem to reappear in one form or another every generation or so. Shimano's Biopace is probably the most famous example; currently Osymetric rings have a following among some members of the peloton.  There have been all sorts of other ways to make pedaling more efficient by eliminating the "dead" spots so that power is transferred all through the arc of pedaling.

Just recently, I came across something I saw in the bike magazines some years ago but never actually saw in person.  It seemed like one of the most bizarre, Rube Goldberg-ian contraptions I'd ever seen on a bicycle.  But, apparently, the idea has stuck around:  The organization that patented it in 2007 was founded in 1998.

At the risk of offending anyone with any sense of political correctness, I will say that the idea is so high-tech and so complex (complicated?) that it could have come from one of only two countries:  France or Japan.   

If you chose the Land of the Rising Sun, enjoy your sake.  OTEC, the company that patented and produces the SDV system, says "The direction of a motion of a pedal in its power phase is designed to coincide with the direction in which the rider can most easily apply force on the pedal while stretching his or her legs."  The result is that its geometry  "makes riders use larger muscles, resulting in lower cadences than expected".  

That is exactly the opposite of what we were all trying to achieve all of those years!  But, in looking at it in motion, I can see how it would make sense for, say, someone like a climber or, perhaps, an individual time trialist.  It also seems to me that it also might be better suited to a recumbent bike, on which the rider pedals from behind, than on a diamond frame, on which the cyclist pedals from above.

I am curious enough to try an OTEC if given the opportunity.  What differences, if any, would I notice in my pedal stroke or my ride?


  1. SDV looks like it would be quite a boon to sprocket makers. May I submit that the humble fixed gear is very good at pulling you past the dead spot in the pedal stroke as long as you have any momentum. I've always been able to climb better on my fix than on my geared bikes.

  2. You said it: Rube Goldberg. I wonder if any real advantage is not overcome by all the additional friction.

    I had an old Biopace on one of my vintage machines for a while. Frankly I regard it too as a (minor) piece of Rube Goldbergery. Never noticed ANY difference. I got it cheap, *really* cheap. The LBS owner found it in the cellar and it was coated in oily dust. I had just about worn out the chain rings on that bike and this was a stop-gap solution. Sudden brainstorm... I took the old (52-42) chainrings apart and flipped them over, like turning over old phonograph records, so the "shark teeth" point the other direction. It works fine, even climbing. I told the LBS owner and he looked a little worried. The chainring is 50 years old, and now it looks like I have found a way to make it last a 100 years.

    Following Phillip's line of thought, combining my system and the SDV, the sprocket market would stay stable as it is now.


  3. Leo and Philip--Hmm, sounds like an odd sort of balance.

    Sometimes I wonder whether all of these brilliant, new ideas are just ways to create new markets for replacement parts.