Ok, for the past few months I have noticed a vibration that would come on highway speeds. I really didn't think anything of it until the virbration got worse and worse. It almost feels like my tire had a flat spot. I figured the wheels were just off balance so I took it in and had the wheels balanced. On a trip of cruising 75-90mph most of the way the vibration was back and seemed to be getting worse and worse. I actually pulled over twice because I thought I might have a flat tire.

Last weekend, I was on the dyno and noticed my passenger rear wheel was wobbling almost as if it was bent. Now I have never blown out this tire or slamed into anything to bend the wheel so what could this be?

 

Are your wheels stock or after market? I had the same kinda problem which was linked to acouple things. First at that speed i think its gonna be balance or a warped wheel, a road force test or balancing should be able to dtermine this. ANother prob i had was when the tires start to get worm down or unevenly worn it will produce a vibration at higher speeds. Also when when switching to after market wheels, you will need to get hub centric rings for the new wheels. I have heard mixed input about that but after installing some hib rings on my new wheels, the vibratino completely went away

 

Let us know if these are OEM or aftermarket rims.

If aftermarket, check to make certain that the rim is interfacing properly with the flat surface of the rotor hat. If the center bore of the rim is too small, it will not seat down past the small lip on the inside of the rotor hat, causing a wobble. Sometimes, the incorrect engagement of hub-centric rings can cause this type of wobble.

If that's not it, take your wheels off the car and have them checked for concentricity.

 

In extreme cases it could be a wheel bearing, axle nut or a bent knuckle or even loose lugs. I'd check the wheel first.

You say you've never hit anything but are you the first owner of the car? If not then maybe the PO did?

 

The wheels are ASA FR1's. I used them for 1.5 years before I started feeling anything. I think these wheels only use centering rings for the fronts.

I think I'm going to take the wheels off and put on my OEM to check if it still does it. I'll keep you posted on what I figure out.

 

It could also be a belt that shifted in a tire come to think of it.

 

You know this made me think. I ran over a screw and had my tire plugged and patched right about the same time that I started noticing the wobble.

 

Non hub-centric wheels are prone to sudden vibration over time, especially if air guns are used to tighten the nuts on. No amount of balancing will fix this, as the problem comes from the wheels centering on the bolts and a play developing over time. This sounds like it's the case here.

 

along the lines of this..also,I just yesterday put on some AP2 17" oem wheels/tires(90%new tires) on my 03..Well,,at slower speeds I can sort of hear a echoing type sound..A flat tire type sound..Now,theres proper air in it,,and we tripleChecked the lugs...I just took to my mechanic..and he ran his hand around the outer part of the tire and said something about "scalloped tire"..that the treads may be uneven due to bad alignment on the last car it was on...I dont know though.
I too have had a bad alignment for a while now and actually am getting it fixed in few days (it wears down the outer part of the fronts..)..So im at a crossroads now and dont know what it could be..I mean,nothing really happens to my steering wheel when braking or slowing down.I would assume I could feel it alot more IF it was a bent/warped rim..If anyone knows at all anything that could help me,please please let me know...(the sound is coming and going..abit bit louder at times but nothing too loud and noticeable til I listen closely.Its aggrivating me bigtime.well,thanks if anyone can help
(also,the kid I got them from said that pretty soon he's going to "get rid" of his new S,so he could swap all of his for the ones on my car)but I dont know how soon that's going to happen...anyway,hope yall can chime in with anything

 

Why don't you believe your mechanic when he said "scalloped tire?"