Jan 14, 2015

Planing Bicycles ???

Bicycle Quarterly is a publication dedicated to the joys of recreation cycling. Masterminded by Jan Heine, BQ's support home page is called Off The Beaten Path.

Along with an appreciation of cycling history and the experience of simply being out on a bike, one of the primary underpinnings of both Bicycle Quarterly and Off The Beaten Path is the desire to pierce the technical veil presented by the bike racing world. Much like pro contest surfing, pro cycling generates a number of misconceptions about equipment and performance. And, much like numerous counter-culture surfing blogs, Off The Beaten Path acknowledges what is great about professional sports, while bringing down to earth some of the BS that goes along with it.

One of the areas of conflict between pro cycling and soul cycling is the degree a "good" bike should flex. The pro perspective, in the past 20 years or so, is that the lightest, stiffest frame will transfer the energy of the peddling rider into the most forward motion. That makes sense...on a superficial level. But, cyclists who ride many thousands of miles a year tend to think that a bit of flex in a frame not only makes the bike more comfortable, it also makes it faster.

Jan Heine and his staff are inclined to objectively test various "old wives tales," and try to either put them to rest, or give them credence. In recent years, Jan has given a name to the phenomenon when a bike flexes as a rider peddles in a manner that actually helps propel the bike forward. He calls it "planing." There have been several excellent, albeit hard to comprehend, articles in Off The Beaten Path on that subject. The links are here and here.

So what's the relevance of "bicycle planing" to mat surfing?

As any mat rider can tell you, when a mat flexes on the face of a wave, it will often times accelerate. This is counter-intuitive for most surfers (and board builders) who feel that a rigid, edgey, flat bottomed board will always go faster. Since surfing is largely subjective, it's virtually impossible to test something like the effects of flex in a manner that can be presented to someone who is skeptical.

In any case, "bicycle planing" is a concept well worth studying for mat riders!


Nate said...

Ha! Finally a cross-over between my two favorite blogs! I've ridden my "flexy" vintage cromoly bike with wide "low" pressure tires from Portland with my 4gf rolled up in my panniers. I was very glad I wasn't on an overly stiff aluminum bike with 23mm wide 120psi tires.

Anonymous said...

I have found that the amount of flex is less important than the interval of response. The sinodial concurance of flex gives you more speed because instead of deflection you get retransmission. This true for any object moving through fluids. Stiff bike frames should be faster but they ignore the riders pain on bumps, which makes them get slower. Carbon fiber is stiffer(interval of response} than steel,but my racing friends still ride steel frames[retransmission].


Anonymous said...

Etta James, had a good handle on it when she penned the Song "It aint the meat it's the motion".