I always thought of 584/650B as a way to get more tire in the right frame size with all the right clearances for fenders, etc. more than any other reason. And that especially for smaller sizes that even smaller wheels - 559/mountain bike size or - in my wife's case, for her mountain bike, 507/24" (she is 4' 10"), are required for stand-over heights, etc. Seeking optimums in moments of inertia, various hysterises (is that a word? what is the plural of hysteresis? hysterii?), aerodynamic resistance, rolling resistance, pneumatic trail, contact patch shape, and so on has to be a matter of...personal taste and much further research? Maybe matching to load and road surface, too...
Amazing how little changes have such strong real or placebo effects... On Sat, Aug 14, 2010 at 9:16 PM, PATRICK MOORE <[email protected]> wrote: > Rob Perks wrote: >> >> The volume of air that affects rolling resistance is the cross section >> of air directly above the area of deformation. Therefore it stands to >> reason that wheel diameter should not play into that. >> > > It is, so they say -- I am not an engineer -- the contact patch (a sign of > which is that tire suppleness affects rolling resistance greatly, indicating > that it is the contact patch and not just air volume) that, all else equal, > determines rolling resistance, and that is certainly affected by wheel > diameter. > Snip. >>WRT to smaller wheels and faster acceleration, I have ridden 26" - 29" >>with all sorts of tires and still feel that the greates factor >>affecting acceleration is the weight not as much the diameter. e. > Not quite, I think. First, it is indeed the smaller size that makes smaller > wheels so light. You save 100 grams or so at the circumference on the rim > and 50 more on the tire, ceteris paribus -- my Sun M14A 559s weigh 360 gr > (and are strong enough that I had no problems at all off road) and the 559 > Turbos and Conti GPs weigh just under 200 gr. And then add the cumulative > effect of taking a bit over an inch off each spoke. My old Ultegra/nothing > special 8-9 sp 559 wheelset weighed about 1500 grams with rim tape, no > skewers or cassette. > Second, most of that weight is at the circumference and we all remember the > Law of Moments. > Again, riding fixed, you can certainly feel the difference. > > > -- > You received this message because you are subscribed to the Google Groups > "RBW Owners Bunch" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/rbw-owners-bunch?hl=en. > -- Bill Gibson Tempe, Arizona, USA -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
