High Speed Front End Shimmy

What is causing the shimmy of my 2004 AND 2005 Saturn Vue Red Line cars?



Worn front steering/suspension components? Front tires with belt seperation?

Tester

A little more info would be helpful.

What speed does it occur?

Does braking change it?

Does turning the steering wheel change it?

The cars have always had this shimmy since new. With new tires, it’s barely perceptable; tires at the wear bars is violent. Here’s more info:

one car has 80,000 miles, the other 140,000 miles

the struts/shocks have not been replaced. alignment shop has not detected any significant suspension wear requiring replacement parts

two different brand tires have been used - original Michelins and currently Kumo; P245R50, Z rated

one set of Kumo tires exhibited tire separation, but were replaced immediately which caused a reduction in shimmy. It is expected that the shimmy intensity will increase as the tires wear

4-wheel alignments (fronts and rears) by a reputable shop with laser type equipment performed several times

wheel balancing performed frequently and by different shops

rotors checked for axial and radial run out - less than .005" total indicated reading

wheels checked for axial and radial run out - less than .010" total

rotors replaced on the 2005 along with new pad, kept original calipers

the shimmy occurs at 65 mph, touching the brakes amplifies the shimmy and “hard” breaking causes violent shaking

steering doesn’t affect the reaction

The cars have always had this shimmy since new. With new tires, it’s barely perceptable; tires at the wear bars is violent. Here’s more info:

one car has 80,000 miles, the other 140,000 miles

the struts/shocks have not been replaced. alignment shop has not detected any significant suspension wear requiring replacement parts

two different brand tires have been used - original Michelins and currently Kumo; P245R50, Z rated

one set of Kumo tires exhibited tire separation, but were replaced immediately which caused a reduction in shimmy. It is expected that the shimmy intensity will increase as the tires wear

4-wheel alignments (fronts and rears) by a reputable shop with laser type equipment performed several times

wheel balancing performed frequently and by different shops

rotors checked for axial and radial run out - less than .005" total indicated reading

wheels checked for axial and radial run out - less than .010" total

rotors replaced on the 2005 along with new pad, kept original calipers

the shimmy occurs at 65 mph, touching the brakes amplifies the shimmy and “hard” breaking causes violent shaking

steering doesn’t affect the reaction