2001 Honda s2000
Car is lowered
I have axle spacers
Wheels are 18x9 in the rear.

I noticed a vibration in the rear after 65+ mph basically freeway speeds. Now, I had my gf drive along side me and she stated that my wheel was moving side to side like its sitting uneven on the hub. I re torqued my wheels and still does it. Possible causes that I'm thinking of: bent wheel hub, bent axle, tire/wheel itself, or lug nuts not seating wheel properly. If anyone has any same experience or knows where I should start first.

 

Sounds like a wheels bearing to me.

All I know is that loose wheels (when torqued down) are one thing to check when buying a new S.

Jack up your car, ensure the lugs are tight, and try shaking your wheel. If it moves or wobbles then you have a bad wheel bearing.

 

+1 wheel bearing. Like previously stated, jack up that corner and hold the wheel at 9 & 3 o'clock, see if it moves. Try other degrees as well.

 

Bingo. Seems like the problem and dangerous if too long

 

i would check on the wheel bearing

 

they are not hard to change but if you dont do it soon it becomes a disaster

 

Did you do the TSB for the rear axle nuts?
https://www.s2ki.com/s2000/topic/929...e-nut-tsb-diy/

 

Try swapping wheels. You may find your wheel is bent or the mounting face has not been machined concentric. Also look to check its not propping on the corner between the bore hole and mounting face.

 

OP: why did you not even try to remove the wheel and have a look?
Or lift that rear side and spin it.
Just adding torque to something that's not right in the first place is not going to make it any better.

Double check the wheel actually fits on the hub, the hub diameter in the rear is smaller than the front - so rear OEM wheels don't fit on the front.
Or at least they don't fit right, many have tried to put rear wheels at the front and then wonder "Why its so wobbely..?"