Joined: Feb 2012
Posts: 19,353
Likes: 5,471
From: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Even frames bikes with identical geometry and components but with differing frame tubing/materials will behave differently WRT shimmy. As shimmy seems to be a harmonic oscillation, frame and component (like wheel/tire) stiffness and rider mass and his stiffness contribute. A rider's stiffness/damping will change from day to mile.
Good luck with your work. Andy.