shimmy, shimmy

[eddief]

I know this has been gone over before, but thought I'd trot out my own experience from the weekend. I had really never felt front end shimmy/wobble before. But this weekend out on my TST ti bike with Kestrel threaded fork after a grueling climb in about 95 degrees, I began a long steep descent and the thing starts to wobble at about 30 mph.

Once I felt it, it was easy to control, but then I got curious and found that a little shaking on the bars made it easy to get it wobbling again.

I've heard this can be induced by rigid arms on the bars, and I gotta tell you I was wiped when I started the descent so the old arms and hands may have been clamped down pretty tight. So maybe the wobble came from driver tightening up.

But I got to thinking about the specs sent to me when I bought the TST and remembered it was spekkt for fork blades shorter than most. I think Profile Design forks have 364 mm blades and Ouzos are 370. Not sure what the Kestrel has in that dimension.

If the wobble was not due to tightness (mine) do you think it could be caused by the trail being negatively affected by having the fork blades, let's say, 6 mm longer than spec?

Do longer fork blades reduce trail and therefore loosen up the steering???

By the way, today I tried the same wobble maneuver on my Kogswell and could not get it to shimmy even after trying multiple times.

[Smiley]

Eddie , you mean that since the fork blades are of differing lengths , then you have a different span for each fork , Yes in theory the differnce in span will raise your front end a tad effecting the head tube angle , in the case of making for a longer span a slacker head angle , this will change the trail but my guess as it was told to me ,very finite and maybe not noticable . Have you checked for bearing play on your front hub first ? I am not surprised your Kogs is rock solid , mine feels like my tandem ...very sure footed and steers dead straight , but it also weighs more then all my other bikes . Good luck finding the problem and maybe let some air out of the tires may help .