Thanks for the synopsis. It sounds like you may be conflating two phenomena. Flexy main triangles exhibit bottom bracket motion under strong pedaling (mostly sideways and rotating). Since metal has quite low elasticity losses energy you put in mostly comes back out. Wether or not that energy release sends a particular rider down the road faster or not is a bit harder to pin down. You may find reading about the early Vitus fames and Seaun Kelly interesting on this point. I think its fair to say that how much of this is how good a thing is debatable. I thought when Jan talked about "planing" he was referring to how the bike interacted with road irregularities. This is about in plane deformations. In that mode the main triangle is so much stiffer than the fork, and probably the rear triangle, not to mention the tires and wheels that I find it hard to credit the suggestion that a stiff main triangle presents a problem there.
I wouldn't say a complete kook, but a bit kooky maybe. Certainly he even describes himself a well outside of mainstream thought on these topics. I suspect that "planing" is only mostly settled in the view of those who believe Jan (which I doubt is a majority of any relevant group except perhaps BQ subscribers). On Aug 6, 6:45 pm, Allan in Portland <allan_f...@aracnet.com> wrote: > On Monday, August 6, 2012 6:18:41 PM UTC-7, ted wrote: > > > Not a sub. > > Don't have time to track down any blog posts on it, but the triangle > stoutness is in the magazine quite a bit, both how he came to discover it, > and how he went on to qualitatively measure it. In short, and taking > liberties with Jan's description the frame is a spring. With the right > amount of flex in the spring, energy can be absorbed on the down stroke and > released as the pedal crest in rotation. Too much flex and the bike bobs, > too little and the spring isn't stretched any. > > There's plenty of quantitative questions still open, but qualitatively > "planing" as he calls it is pretty well settled, unless one thinks Jan is a > complete kook. As he said in the blog, he's ridden some 50 bikes in the > last 10 years like a borrowed mule. (OK, I added the second part.) I'm > inclined to believe him on this point. > > Regards, > -Allan -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
