A4 s-line 140 TDI with shudder

[whittle]

Hi All,

I am looking for some advice to be honest.

After recently purchasing an A4 i have discovered a problem that i cant figure out. The car is still under warranty so at least i can get the car sorted. The main problem is the garage don't seem to know what the problem is

The car, well it has 30,000 miles on and before i had the car it has had 4 new tyres all balanced and checked, serviced the norm really for a used purchase.

The problem i have is a shudder between 60 - 85mph to be honest i have not passed this speed to see if is gets any worse. I really enjoy driving the A4 but this is really annoying, I thought the whole audi experience with the A4 was comfort and stability at motorway speeds.

Does anyone have any idea what could be causing this, with the new tyres and balancing i guess the running gear can be ruled out. The problem did not appear to be there until around a week of owning the car??.

I have read a couple of reports regarding control arms could this be part of the fault, I'm really lost with this and with the garage not test driving the car over 70mph i just don't know what to suggest.

Sorry for the log thread!, Thank you all in advance!.
Andy

[Pork]

I think the best thing to do is start with the basics.
If the new tyres were already fitted (just) before you bought the car, the most likely culprit would be balancing.
I'll make an assumption that the tyres were fitted at the car sales premesis by a mobile fitter and that they don't have the best reputation for balancing 100%.
Even if this isn't the case my money would still be on the lost wheel balance weight scenario. ie was ok for a short while, then the vibration appeared.
It's possible the garage didn't even get the balancing re-checked when you took it back too.
If you don't mind half an hours work, my first suggestion would be to swap the wheels front to back and see if the shudder changes (felt in the steering for example)
Alternatively, if you have the receipt for the tyres with the paperwork, why not pop along yourself and ask to have them rebalanced?

[whittle]

Thank you for your reply,

I had the wheels balanced again by an independent tyre company. To be honest that was my first thought.
Just before purchasing te car the garage had the wheels refurbished and new tyres. Everything was fine for the first week. I wondered if a weight may have fell of.

So rather than taking the car back to the dealer i thought i would take it somewhere else just for piece of mind to be honest.

I think i will change the rears to the front to see if there is a difference but seems strange as all the front are now balanced perfectly,

Thanks Again

[Pork]

Could be a flat spot on the inside edge of one alloy, when you've got it up in the air give them a spin and check the inside and outside lips run true??

[mcmolloy]

Did you get your problem sorted?If not it could be a warped brake disc on the rear.I had this vibration on my car and thats what caused it.

[SebRogers]

Could also be an out-of-round tyre. It does happen, especially with the cheaper brands. This happened to me and it'd be the first think I'd check if the tyres are brand new...

[Deakin]

I changed three wheel bearings unnecessarily in an attempt to fix rumbling/vibration issues. Turned out to be the tyres, Dunlop Optimax's. They'd gone the shape of threepenny bits. Very frustrating as they had to be changed at less than half worn. Found out by switching to my winter wheels and tyres a bit early. I'd certainly make sure I exhausted any possible tyre issues before I spent money on investigating suspension issues.

[Deakin]

oops. I mean Optigrip.