Baloo588

I got my all seasons tires and rims bolted back onto my car after taking the winter wheels off. The car has a buzzing vibration that comes and goes every 1 sec (cyclical) from the rear of the car felt in the seats around 70-75 mph. Do you guys think its a bad tire or out of balance wheels/tires?
I didn't feel this before when I stored the all season tires/rims. The winter tires were a slight rougher so I can't compare it but I know that these continentals were smooth as glass last fall… I doubt it would be a tire that went out of round as it was inflated properly before storing it.

Free4134

Have had that sometimes when the cold car had been sitting on uneven pavement for a couple of days. Subsided after a longer run that warmed up the tires.

You might want to inspect the tire surface thoroughly for any objects, check the torque of wheel nuts and try a higher tire pressure.

If the symptoms persist, the tire may have lost roundness if prior use was predominantly in an unloaded state on the rear axle.

Baloo588

You might be right that one of the tire has lost it roundness. I am getting the rear tires road force balanced on a hunter machine and we will replace the bad tire with a new one that I have ordered. I think the tire went out of round when it was not stored at proper pressure (someone at the dealer must of not inflated the tire up to 40 psi before putting the wheels up on the storage racks for 4 month). No vibration from front tires.

Baloo588

Update,

The back wheels where road force and they were perfect under 10 lbs and balanced well so they are ruled out. My dealer is going to do the front wheels tomorrow morning and check the bearings, cv joints, suspension, drivetrain, etc because that buzzing vibration is still there at 70-85 mph zone only.

Baloo588

Left front wheel bearing shot. 2 front tires were out of road force balancing specs. They re-road forced it and got it under 10 lbs. They will test drive it properly on a smooth highway tomorrow. Will update! BTW, wheel bearing was under warranty.

Baloo588

That did not fix the problem. I got 4 new michelin pilot sport a/s 3 tires replaced and road force balanced on the car. The dealer knew of the persistent vibration (high frequency ) in the chassis, center console, and seats on the highway. They called in the technical field manager who test drove the car and inspected it further. They pointed to the driveshaft as being the culprit so they rotated the driveshaft which did not improve the vibration. Thus, i was fed up so they will be ordering a new driveshaft from german and will arrive in 3-5 days.

I knew it was something not tire/wheel related and something in the car. I have done 50k miles on my first 2006 Audi A8L and 150k miles on the second 2007 Audi A8L. So I know how the A8s are suppose to ride and feel. This one is a 2012 with 50k miles in 2 years and I hope to get more out of it.

Baloo588

GOOD NEWS!

The dealer replaced the driveshaft and the vibration is gone!! Glad to say that the A8L is smooth as glass as it should be. I have to give kudos to Audi and their factory representative and mechanics for being patient and doing the best for the customer.

I have to admit that many people are not taking part in this post or making any recommendations/suggestions because they have not had this problem before. I understand that. Its important to give tips and updates on this forum since no car is immune to impeccable build quality let alone the Audi A8L. There are many issues with the older ones and I feel many of the older A8 owners have chimed in more then the newer generation A8s. Hopefully that will change over time.

Dennis Gautreau

Hello, I have something similar happening at about 40MPH give or take. I wonder if its the same thing. Seems to be resonating from the center of the car or toward the rear, I don't feel it in the steering at all. It goes away at about 42mph but very pronounced at 40.

Jack88

I think it's a different problem. Nobody seems to know what it is, but quite a number of people have reported it specifically around 40mph, including myself. The issue presented in this thread occured at a completely different speed.

Dennis Gautreau

I realize that this thread talks about a higher speed but the thing that got me thinking it may be the same issue is it is cyclic, not a random vibration like out of balance tires. I'll have to look for the thread you are talking about, I didn't see it when I started searching for my issue.