> On May 16, 2025, at 1:31 PM, Ben Miller <[email protected]> wrote: > > This is effected by design of the tire, tread, surface conditions, > suspension, "planing" etc.
This brings up an interesting and, for me, surprising aspect of the data comparison I made in my original post. The Cheviot is definitely not a “planing” (terrible use of that word, I prefer “swinging”) frame. Stiff as a big, steel I-beam in my experience. The Terraferma is a Jan-approved noodle, skinny tubes, thin walls. I’m light and weak, but I can pretty easily deflect the bottom bracket enough to make the chain hit the front derailer. Without thinking too hard about it, at my commuting speeds, “bike drag” (the whole bike/human rolling resistance bag of stuff) should be more of a factor, relative to wind, than at my recreational riding speeds. So, the difference in position doesn’t make a big difference at the speed, but surely the springier bike would be faster. Thinking more about it, though, Jan has (mostly, not always) been clear that what he calls “planing” is an effect that shows up in high-effort situations, like climbing at high speeds. I’ve seen finite element analysis that confirms that notion - for a given frame, there is a level of effort at which the “swing” kicks in. My commuting level of effort is below that level for both frames. My perception of slowness/stiffness/responsiveness/swing really only happens at initial acceleration from a stop or when giving a little extra effort to climb the tiny hills on my route, i.e. for a tiny percentage of the total time riding. Those perceptions certainly contribute to how I feel about riding each bike, but they don't show up in my data on average speeds. Back to upright vs drop bars … that whole bag of stuff that amounts to bike/human rolling resistance includes the leverage and spring characteristics of handlebars and hand position. And, speaking of that, and Bicycling Science … Gary Boulanger (Riv employee who worked at Waterford during the epoch of Heron) and I went for a ride one day. As we left Thiensville, climbing the 8% bugger of a hill going west, we came upon a somewhat scruffy, not terribly trim guy riding a Columbia 3-speed. He casually matched our speed and chatted breezily with us as we climbed the hill. Not a bit of windedness to him despite the effort. Introduced himself as Jim Papadapoulos, a major contributor to much of what we know about bicycling science. Ted Durant - still using the Second Edition, but those equations haven’t changed :-) Milwaukee WI USA -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/rbw-owners-bunch/DFD1E894-3EC1-4E37-8E6A-5DF1F319474D%40gmail.com.
