On Mon, 2010-08-09 at 08:44 -0700, Bob Cooper wrote: > It’s a cold, sunny spring morning, and I’m shivering slightly.
That right there is enough to initiate a shimmy. > I hit a bump in the road hidden by a shadow from a tree. > > I tense up And per the FAQ that itself is a contributing factor in shimmy. > and apply the brakes a little. I sit down reflexively to > lower my center of gravity, which we all do when it looks like we are > going to fall. To not do this requires extraordinary will power and > confidence. > > Instantly, your Quickbeam starts to shake violently. > > My arms go stiff, and I grip the brakes harder to make it stop, but of > course all this makes it shake harder. Quoting from the FAQ: > Shimmy that concerns riders the most occurs with hands firmly on the > bars and it is rider generated by muscular effect whose natural > response is the same as the shimmy frequency, about that of Human > shivering. Descending in cold weather can be difficult for this > reason. The rider's "death grip" only enhances the incidence of > shimmy in this situation. Loosely holding the bars between thumb and > forefinger is a way of avoiding shimmy when cold. -- http://www.faqs.org/faqs/bicycles-faq/part4/section-25.html Plenty more good info about this phenomenon at the above URL. > > No one has been able to satisfactorily explain this phenomenon. Many > have tried; all have failed. On the contrary, although some aspects are a bit mysterious the FAQ has lots of successful explanation. > I watched the video that Jim G made of his bike shimmy. I couldn’t > make a video of this on a big descent, because I can’t do anything > when it starts. It’s progressive. It’s violent. It’s profoundly > frightening. Your description fits classic speed wobble perfectly. If so, it's NOT what JimG had. That's the "other" kind of shimmy. And by the way, I agree, there's little in life that's more frightening than speed wobble. -- 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-bu...@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.
