Baloo588

Hello,

I am in a dilemma. I have been balancing my wheels few times and even put the winter sets on and I still get some vibration felt in both the front seats on the highway above 70 mph that gets more and gets less depending on the road surface. There is no steering vibration nor any vibration in the back seats when sitting there which rules out tire/wheel vibration. I wonder since my car has high mileage that the suspension is failing to dampen road irregularities and vibration happens from the front suspension. Or control arm bushings are gone since there is some noise at low speeds over bumps? This is unusual since when I am sitting in the back seat of my A8L the ride is super smooth over the same roads but when sitting in driver's seat the vibration is felt in the seat back and bottom and even in the passenger's seat. Its does not feel like out of tire balance as it is ruled out and swapped out to winter sets and with perfect road force balance. The steering wheel is solid and smooth. So I am wondering should this car require new struts especially in the front or control arm bushings replaced? My dealer says the all 4 control arm bushings in the upper part needs replacement but i am not sure if that is the cause of vibration as steering wheel is fine. How about driveshaft becoming out of balance and loose including the central bearing support that leads to vibration in the front seats only. Even putting the car into neutral on highways does not help.

mishar

Start with fixing what's obviously broken an has to be fixed anyways. Control arms bushings and alignment first. Than check drive shaft central bearing mount, all engine and exhaust mounts.

I don't think struts can make such vibrations.

MP4.2+6.0

Agreed w/ Mishar on doing upper control arms/bushings. They just don't last to that mileage w/ out issues. At that mileage and since you should do an alignment anyway, I would also do the tie rod ends if they were not previously replaced.

After that, I would look for bent wheels before looking at things like driveshafts. At that mileage you could have one or more bent wheels in BOTH sets. BTDT on my 4.2 A6 recently, after rolling thru these same front suspension parts. Each repair improved things, and the multiple bent wheels across two sets caught me by surprise when I went to have them re balanced at mid life during a summer to winter swap over. No guarantees, but turned out the suspect wheels (all OEM) invariably also had or called for more than a couple of ounces of balance weights if the bent wheel wasn't otherwise caught by the tire balance guy.

Baloo588

Excellent plan. Thank you to both of you. I have had bent rims before but these have been checked on both the original 19 inch turbine wheel sets and my winter sets and they are all true and take little weights. My winter sets are new Hartage wheels and I have made sure that they were true on the hunter road force machine after having a bad set of Sports editions that vibrated the entire car and the steering wheel the previous winter. So that is ruled out at this time. I will start with the replacement of the control arm bushings as recommended by my dealership this spring after putting the original wheel/tire set back on and go forth deeper into the driveshaft, central bearing supports, etc IF there is still vibration after the control arm bushings are done. The alignment has been done last summer after mounting new tires so its all good. Other than that I hope I do not have to shell out too much money chasing vibration as I know its a annoyance. This vibration is small and some people can feel it while others cannot. I can definitely feel it and its irritating.

mishar

When you fix bushings you have to align front wheels again.

AusA8

I'll follow this with interest as I have a very small vibration that I've only recently noticed. Let us know if the bushes fix the problem.

Cheers

Baloo588

I will keep all of you posted. As I am one of the high mileage driver so that others will know what to do when these problems creep up at later times.

sketch44

http://www.tirerack.com/images/tires/vibechart.pdf

Great chart.

Having vibration at 60-70mph on my Audi allroad.

Possibilities to eliminate:

CV Axle (already put in one Raxle CV for a torn boot)
Older control joints
Tires
Wheels

Next, I'm having a tire balancing specialist with the fancy force balancing equipment analyze my tires and wheels to eliminate that as a possiblity before we get into the more expensive solutions.

He has already taught me a few things about how tires all have high spots as do wheels and that if they get lined up they will give you all kinds of problems.

25/tire for balancing and 12.5 per wheel with no tire in Denver.

sketch44

OK,

So I found the culprit. Ghetto wheel installer. Had all sorts of different kinds of weights on them and had the directions wrong on the tires. BEWARE CHEAP TIRE SHOPS!

Spent 25.00 / wheel to get them rebalanced with road force and they are PERFECT now. No vibration and the car tracks straight!

I love driving this car on the highway again. Sooooo smooth!

If you are in Denver give Chris at Tires on Site a call. He sells tires and rebalances and knows what he is doing!

jmhjgh

Mishar: why do you need an alignment after control arm bushing replacement? I would think the length of the control arm is not changing and should not need an alignment. I am looking at replacing my control arm bushings since I am starting to get lots of squeaking and groaning.