When I bought the '08 and drove it home I thought it was a little noisy. It needed two rear tires so I matched the new ones up with what was on the front. They were available because they were Pep Boys Starfire cheapolas. After mounting them the road drone was even worse. That makes me think the tires are at fault. It only appears over 50 mph and gets worse the faster you go. If you open a window it goes away. My '05 has Tiger Paws tires and also has a slight drone but nothing like the '08. The Tiger paws have a 700 tread wear rating making them a pretty hard compound. The Starfires have a 400 tread wear rating. You would think the softer compound tire would make less noise. The only test I can make is to put my set of winter-only Blizzak tires on and see if the sound goes away. These are extremely soft and quiet tires. I don't want to do that while it is still 80° out. I was wondering if this is a common thing on these Cobalts?