SL500 96, shaking

Hello
Does anyome have a suggestion what to do about a car, shaking at almost all speeds.
I have had new tires, so no flat spot. Didn't help. I have wheels ajusted so that they are correct in line. Didn't help.
I have new wheelspacers. Didn't help. I have the wheels ballanced while sitting on the car. Helped a little bit. The wheels are chekked and are 100% round and straight. Didn't help.
It seems that the problem gets worse as it get colder. Over 24C / 73F the problem almost dissapers. The car has not automatic/manual level control. The wheel are Azev 18x8,5 and 18x10 and the tires are Bridgestone Potenza
Any help will be appriciated.
Michael Denmark
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Could be: shocks, tie rods, ball joints, steering damper.
Did it happen with the stock wheels?
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Two thoughts:
1. These tires are larger than the originals and have a greater effect on the car. So ANY problem will be magnified vs. an original size tire.
2. That the problem is temperature related points to the tires - tires get flat spots from standing but such flat spots disappear as the tire warms up from flexing while driving. These wide, low profile tires don't flex much so it may take more than a km to warm them up. Performance has its costs.
You can test this. Park overnight and, on a cool morning, before driving, draw a chalk arrow on the tire to its ground contact point. Jack up that wheel and rotate it so you can feel the flat spot at the arrow (or not if there is none). Not scientific but may prove the point.
If it were my car I'd ask the Bridgestone factory representative to check these tires and specifically comment on their characteristics vs. #2 above. You may find out that "that all do that" - common auto industry excuse to not deal with a problem - or, you may be given new tires!
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Does this "wheels adjusted" means a full geometry Alignment, not just "in line", but camber, caster, etc.? I guess so, judging by the amount of the tires and rims purchase. Did they inspect ball joints, bushes, tie rod ends, before the alignment?. They usually do it, the car suspension must be in good shape with no worn out parts, for proper alignment.
Though I dont see a direct connection with them and the temperature influencing the vibration, just in case, check the motor mounts. Do a search in this group, there is a simple way to test them.
I just recently equipped my W210 and my W124 with Bridgestone Potenza tires (japanese made). They have great ride, excellent grip and no flat spot at all (it's winter down here, 2C in the mornings). Anyway, see what happens overnight with a higher inflation pressure, add 3 - 5 psi more than normal (with cold tires).

all
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mb wrote:

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MB: INSPECT DRIVE SHAFTS CONDITION. OUT OF BALANCE OR LITTLE DAMAGE TO THIS AREAS CAN CAUSE SAME PROBLEM.(VIBRATION). GOOD LUCK
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So, is your shift key broken? Or are you using an old Apple //?
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Thanks for your help.
I put up the tire pressure to 3,3. That helped so that the car didn't shake when driving after a longer stop.
One wheel was sitting a little bit out of adjustment (1 mm at the tire edge). Removing a little bit of rust on the brake disk got it down to app. 0,1 mm.
So now it seems to be OK.
I made a good tool for cheking. A wire wrapped around a stone with one end sticking up like a swan neck. This I then put next to the wheel with the car lifted and I could easily see any misadjustment of the wheel.
Michael

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Is this 33 psi or 3.3 bar? The last one is 48 psi. It seems too much.
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The made in Germany Conti's on my car are good to 51 psi.
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I guess you really want to save on fuel. It makes sense these days. I took a look at the side of my Bridgestones though. It says 44 psi, max. pressure.
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