SL/R230: Wheel shakes as I accelerate past 60.
07-22-2004, 03:01 AM
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04 SL55 (sold),05 SL55, 09 SL63, 07 C2S cab Porsche,
Wheel shakes as I accelerate past 60.
Anyone experience a shaking of the steering wheel around 60mph . It is only there for about 10 mph(50-60) then it smooths out. I thought it might be a wheel balance issue but I don't think it would go away at higher speeds. Any ideas.
George
George
07-22-2004, 04:59 AM
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An unbalanced wheel causes sinusoidal excitation of the suspension system. A rough calculation shows that at 50 mph, this is at a frequency of about 10Hz. Like any spring mass damper system, the suspension will have its own resonant frequency, and when excited at or around that resonant frequency, the amplitude of the resulting displacement will be at a maximum. That explains why, as you accelerate, there is a "sweet spot" where the amplitude and hence vibration in the steering wheel is at a maximum; once you go above that speed, the amplitude falls away and so does the vibration.
Upshot of all of this is to have the wheels carefully balanced. You may have lost one or more stick on weights from the back of the wheel which have caused it to go out of balance, assuming of course you haven't hit anything. If you have, you need to have the steering geometry checked.
Upshot of all of this is to have the wheels carefully balanced. You may have lost one or more stick on weights from the back of the wheel which have caused it to go out of balance, assuming of course you haven't hit anything. If you have, you need to have the steering geometry checked.
07-22-2004, 08:53 AM
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Balancing
Are you running on stock rims and tires? I've had this issue with another car with aftermarket 19s. If they are aftermarket make sure when you get the balancing done that their machine is capible of performing whats called Road Force Balancing. I went through roughly 3 balances from different shops until I finally resolved the issue. Otherwise if you are running stock I would take it back to the dealer for them to resolve. Good luck!
07-22-2004, 11:28 AM
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SL550
I have the same problem. I have stock rims and tires, so I would not have this problem, and have had the wheels balance. The shaking was less after the balance but started again after 20 miles. The car shakes from 55 on. Its worse than my Range Rover with 22's. I am taking it in again next week (3rd time) and I only have 800 miles on the car.
07-23-2004, 11:13 AM
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996 supercharged C4cab widebody, x-5 (4.4), sl-55 kleeman, RR
2 things. either wheels are not balanced. or herniated tire usually on the inner side wall and/or dent inner lip from pot hole.
