It's impossible to know the characteristics of any car in a week so what you're hearing might be normal. What you should do though is keep an eye on the tire wear patterns. If there is an alignment problem, that won't show up right away. There's different wear patterns that will show up for different alignment issues, but the one that will make noise can be felt by rubbing your hand across the tread. Each block of rubber should wear evenly and flat. When one edge is higher than the other, you'll feel your fingers slide smoothly across the tread in one direction, but going the other way your fingertips will catch on the raised, sharp edges. You should not find those raised edges when running your hand up and down the tread or across it. Also, this is the only type of wear that will always affect both front tires nearly equally. When this wear gets bad enough, those raised edges become like little paddles. They make the tire tug through snow really well, but that is also what sets up excessive tire noise. The clue to this is you won't hear it on gravel roads or on wet roads. Both conditions allow the tread to slide across the road as though they were lubricated.
You won't hear nails and rocks in the tires' tread. Tires that are "brand new" can mean different things to different people. Alignment wear takes at least a few thousand miles to show up, (unless the alignment is really off by a lot), so if these tires are less than a few weeks old, the noise isn't due to an alignment problem.
Also be aware that tire wear rates, traction, resistance to heat buildup, and noise are characteristics of all tires, and trade-offs are made in the design to minimize one or two of those things at the expense of the others. A tire that wears well will last for many miles and come with a really long mileage warranty, but that rubber is harder so it will have lower traction on dry pavement. A tire that is designed to be very quiet on the highway will have very smooth tread with small grooves so it will be less resistant to hydroplaning on wet roads.
Tuesday, February 10th, 2015 AT 10:06 PM