Hello Angus, et al, The scenario is this:
I’m riding Angus’ Quickbeam down Italy Turnpike outside Naples, New York. Your Quickbeam has just been serviced by a great mechanic. The frame is straight; the wheels are perfect; the tires are perfect; this headset is perfect. By coincidence, the fit is perfect. I have my spare tube and a set of allen wrenches in a little bag under my saddle. It’s a cold, sunny spring morning, and I’m shivering slightly. The fast guys are pulling away from me at 53 mph. I hit a bump in the road hidden by a shadow from a tree. I tense up 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. No one has been able to satisfactorily explain this phenomenon. Many have tried; all have failed. 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. My 55 cm Raleigh with oversize aluminum tubing does this. My 59 cm Peugeot PX-10 with one-inch top tube does this. All bikes do this, when I am the rider. All of my bikes do this at almost any speed, even 15 mph, but the story ends differently at lower speeds, because I’m not frightened out of my wits at 15 mph. To stay relaxed on a bike that going fast and going out of control is very difficult. When the gradient ahead is INCREASING, it’s even more difficult. Experience, skill, confidence, will power. Sometimes I have these at my disposal, sometimes not. Regards, Bob Cooper -- 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.
