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I have a slight judder/vibration on an Audi S4 which is felt through the car (not the wheel). It is felt normally at higher speeds (70mph) and is not always present. When I originally bought the car (used) a mechanic who inspected noted that there was some play in the offside control arm (unfortuanatly he didn’t state which one, of which there are 4). I’ve since had the car checked by two other mechanics - one couldn’t find any play, but one could in the offside lower rear arm.

The mechanic who found no play said this could be due to weather conditions (wet and dry for example). He did do a road test and could hear a very slight noise on the offside which he said shouldn’t be there (I cannot hear it), and advised me to wait until my next service to see if it has worsened and to look again.

I find the vibration annoying so would like to get it fixed sooner than this, however the fact that the above mechanic couldn’t find any play concerns me.

My wheels have been balanced several times, every time I get them balanced the next mechanic to do the balancing says they were previously out of balance, which seems quite odd to me. I’ve not had them aligned.

I’m due to have my tyres replaced soon, so this is perhaps a good troubleshooting step which will occur “naturally”, and allows me to eliminate one source of the problem.

Is there any other way I could be more certain about the cause of the problem?

  • Some vibrations are hard to solve sometimnes, it could be a bad tire, even if it is perfectly balanced it can cause a vibration. – Moab Jun 14 '18 at 22:16
  • I hope they were dynamically balanced on car vs off car in case brake rotor or axle contributes to imbalance. Slack in wheel bearings or control arms or any moving parts can also rapidly increase tire wear. – Tony Stewart Sunnyskyguy EE75 Jun 15 '18 at 4:33
  • @Moab - I had not considered that a perfectly balanced tyre could vibrate due to a bad tread. I am changing the tyre soon as their tread depth is currently close to 3mm so that will eliminate one factor without additional cost – Mike Whitby Jun 15 '18 at 5:02
  • @Tony Stewart - I was not aware that this form of balancing was ever performed to be honest. My assumption was that all balancing took place by removing the wheel with tyre from the car and placing on a separate machine. Would you say balancing on the car is common, or is it something you would seek a specialist for? If done on the car would you say that bad suspension parts would have a play in the balancing? It would be useful if they did being as this is my current suspect problem area. The car also has 10mm spacers due to a brake upgrade kit, I don’t suspect these to be at fault though – Mike Whitby Jun 15 '18 at 5:07
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As moab says..firstly have the tyres inspected, as out of round tyres will cause this, even new tyres can be out of round.

Also have the inner wheel rims carefully inspected too. In quite a few cases I have seen vehicles with bent inner rims causing vibrations throughout the vehicle, especially if the bent rim is fitted on the rear of the vehicle Running over rocks or bits of woods etc at higher speeds can cause such wheel damage and thus vibration.

  • Wouldn’t a wheel balance reveal out of round tyres, and correct them? I’ve never seen any single one of the mechanics actually doing the balancing, however my assumption is that it is done on a balancing machine where the wheel (with tyre) are removed and the machine spins the wheel and identifies any vibrations and (I presume) advises where (or the mechanic knows where) to place weights to counterbalance the shape. I’m not familiar with how it is done in practice so my assumptions may be quite wrong. – Mike Whitby Jun 15 '18 at 4:58
  • Wheel balancing will show up and correct out of round tyres on the machine, but it only corrects the error in the rotating weight. A physical defect like a bent rim or out of round tyre will still cause a bouncing effect on the car, and this can be felt through the whole vehicle. It doesnt take much of a bend in an inner rim either to cause such a vibration. I once saw a Toyota Avensis with a slightly bent inner rim that shook the whole car at anything above about 40mph. It felt like a balance issue at first, but it was the wheel moving up and down as it rotated that gave that effect. – Orb Jun 15 '18 at 5:23
  • yes I suppose that seems quite obvious now you say it. I did go to one place (The Wheel Specialist) who originally told me one wheel had a flat spot (I replaced it) and they said the replacement was true (it was second hand so I wanted them to check, so I am taking them on their word the wheels are true - I presume they put the wheels on a balancing machine with no tyre to check, as I imagine this would detect any imperfections in the rim? They have visually inspect, I'm not sure. In any case, being as my issue is intermittent would you say this implies it is not the wheel though? – Mike Whitby Jun 15 '18 at 7:59
  • If the problem is intermittent at 70 mph its not the rear rims that are making the car vibrate, however make sure bad road surfaces are not just masking it. On a balance machine you would see a bent rim and could certainly test for it using a fixed point as the wheel rotated, this is assuming the wheel alone was checked, as a fitted tyre could obscure a rim problem. At some tyre places the guy would probably need informing of the issue you were having too or it may be overlooked as just a tyre balance job. – Orb Jun 15 '18 at 8:59

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