1997 E320 - car has new tires checked and balanced on latest Hunter balancer. Dealer aligned all four wheels after installation of new tires. Car has been inspected by dealer for any problems with suspension components including the oft-talked-about lower control arm bushings. Dealer says everything is tight. Yet I still have a mild-moderate vibration coming thru the steering wheel right at 60 mph which feels like a tire out of balance. Funny thing is that during a recent very cold spell here in the midwest (temperatures down to 10 degrees or so), the vibration was greatly diminished if not done away with. Car has 60 k miles on it. Tire pressure has been kept at constant at 29-30 psi. Tires are Bridgestone RE950's on 17" AMG monoblock wheels. I have another appointment with both the tire store and the dealer in the next few days. Does anybody out there have a possible explanation? Does anybody have any ideas about how to troubleshoot the problem? I will get rotation and re-balance when I go to tire store even though the tires have less than 4k miles on them. TIA.