Continental ExtremeContact DWS tire balancing issue at Discount Tires

[alia176]

This is a bit puzzling to me so maybe y'all can enlighten me on something. I bought a set of Continental ExtremeContact DWS few months ago at Discount Tire. The tires are slightly out of balance and I've returned to DT for three weeks straight. Strange thing is that every time I returned to DT, the same balancer showed the tires to be out of balance! I leave the store each time with a perfectly balanced set of tires!

Any speed over 65mph produces out of balance issues. While driving down a newly constructed part of the hwy, I can feel the car vibrating and the front pass seat vibrating on the same frequency. Steering wheel has a very slight shimmy on straight road and more noticeable shimmy on long sweeping turns.

The rims are true and no humps.
The tires have no humps.
New BJs
New tie rod ends.
New all struts, rubber mounts and isolators.

So, I took the car to another tire shop near my work. They balanced just the front tires and this time, the steering wheel is shaking back and forth after I hit the hwy. This steering wheel shimmy is the worst so far! I returned there few days later and had them put the tires on the spinner. Right front tire was still balanced and required no weight. The left front was out of balanced and it was re-balanced. STILL, the steering wheel shimmies, just not as much. During long sweeping turns on the hwy, the steering wheel shakes badly. This is very annoying.

So, I'm puzzled as to why there high quality tires not producing repeatable results on the spinners? When they leave the shop each time, they're perfectly balanced - I eye witnessed them each time. However, driving on the tires produces a different result on the hwy.

All suspension work was done by me so I know it was done right. Everything but the springs and the arms bushings were replaced. Car drives great, sounds fantastic (as in no clonks) and these tires really cut down on the road noise.