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Old 09-24-2023, 04:30 AM
tempest411 tempest411 is offline
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Quote:
Originally Posted by andrewwynn View Post
https://apps.apple.com/app/id298840058

You this app or similar (one that samples sound and plots FFT).

https://apps.apple.com/app/id448155923

Here's another.

Either of those will pull out the frequency of the noise based on the vibration and instantly identify if the vibration is pre or post differential.

7.3 ft is the circumference of the tire. Convert from speed to RPM and compare to the frequency of the vibration.

If it's 1x wheel RPM you're looking at bearing, tire balance etc. If it's 3x or 6x looking at CV joint, if 4.1 or 3.9x (depends if 3.0 or 4.4 motor), it's drive shaft related.



https://apps.apple.com/app/id1089589547

The other app I use is this too measure the shake vs. the sound. Works better for the wheel side shake.

The 3x had helped several people home in on CV axle as the shake.

The speed you described is exactly where the control arms will cause a shake but usually while gentle braking.

Coast at 50mph and gently brake. Stop and start soft braking until you get below 40. If that causes shake you can feel on the steering it's the front sideways control arms. Under the right load conditions it can cause the same shake. Theoretically the rear control arm similar but you should have inner edge tire wear on the rear at that point.

The other test for front inward control arms is to cross over the crown of a road going ≈ 60-65 mph very gently holding steering with just thumb and index finger. (I usually do this test center lane of freeway). You can s-curve and stay in your lane.

If the control arms are shot you'll feel 2-3 wobbles in the steering as it crosses over the "noon" position.

Thank you for your suggestions. I downloaded the version of the first application for my Android phone, and will see what I can find out with it the next time I drive it. The best analogy I can give you on the sound/vibration frequency is that it's roughly the same as you would hear and feel driving over those 'rumble strips' they've been putting on the sides of roads in my area for a while now. If you don't have these where you are, the picture should let you guess what they might sound like driving over them at 40-50mph.
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