Beam axle shimmy
Beam axle shimmy
(OP)
If all joints are rod ends(tight) and wheels are not damaged mis-made or out of balance, where, if anywhere, left is there potential for shimmy? I keep hearing shimmy is caused by gyroscopic forces which act through loosness in the suspension, but what are these gyroscopic forces caused by generally?





RE: Beam axle shimmy
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RE: Beam axle shimmy
As Pat says, it is generated by an out of balance/round of the tires. An out of balance, side to side, wheel/tire could cause gyroscopic precession and contribute, but in some of my earlier experiments, I found this not to be the main cause. The shimmy is almost always caused by wear pattern/out of round in the tires combined with insufficient toe in and a general 'looseness' in the steering box/tie rod, etc.
Rod
RE: Beam axle shimmy
also all the stuff already said
RE: Beam axle shimmy
The book's at home, but I kind of recall a one wheel bump providing a true gyroscopic input that could trigger misbehaviour.
RE: Beam axle shimmy
I remember being in a car that exhibited that sort of behavior, though I don't remember the year/make/model involved. Too many decades ago, I guess. Anyway, whoever was driving had to slow the car down every so often to make the shaking stop.
Norm
RE: Beam axle shimmy
Rod
RE: Beam axle shimmy
Cheers
Greg Locock
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RE: Beam axle shimmy
Rod
RE: Beam axle shimmy