Odd click noise

Hey all,
Ive done some searches but havent found any threads describing what Im hearing...

I only have 600 miles on my 08 package 2, and this was the first super nice weekend so the first I drove with my windows down. Anyways, when driving with the windows down, I hear a continuous 'clicking' noise that gets faster as I speed up (it sounded to me like there was something attached to my tire whacking the ground every time the tire span around). It sounded to me from the driver seat like it was coming from outside on my side of the car...my wife in the passenger seat thought it sounded like it was coming from the outside on her side of the car. I cant see ANYTHING on the tires, any of the axles or anything, and the 'clicking' is very faint (i dont hear it when windows are up, and with windows down if i turn the radio on to volume of about '10' i cant hear the click, and above about 25 mph i cant hear the click because of the wind noise). O, its also only really noticeable when im driving on a road next to a brick wall or something so that the sound reverbs off the wall at my car, if im on a road with no curbs and no brick walls on the sides, i dont really hear it either.

Since this is the first time I drove with the windows down, I have no idea whether this 'clicking' is normal or something to be concerned about...(note that i always hear it, during accel, coast, braking, etc).

Any ideas? anybody else hear something similar?

(in better news, a wooden box fell off a truck in front of me on the highway yesterday and I had to make a quick lane change maneuver at 75 mph...i was very happy with how the prius held the road...there was more sway in the body than I would ideally like...but im pretty sure the same maneuver would have put the ford expedition i used to drive on 2 wheels or worse.)

 

Thanks all...this is what I figured and will inspect the tires more carefully tomorrow (dont worry...i wont be driving it before then). I just wanted to make sure the click wasnt some sort of usual thing that everybody has or something since Ive only had the car for a month.

 

alright so i jacked the car and looked at all 4 wheels...nothing of note, removed some little pebbles but nothing that could be causing the click.

My rear passenger wheel seems to be 'rubbing' though. When i spin it, it will spin freely about 3/4 around, then in the last 1/4, I can hear a friction like sound and the wheel slows some, and then it free wheels again for the next 3/4 turn before again rubbing. The read driver side does not do this and free wheels all the way around.

I engaged and disengaged the parking brake a few times, same result. I pumped the normal brakes a few times, same result. I then drove around the block and parked and raised it again, same result...

This shouldnt be rubbing, right? I called the dealer and he said the e-brake adjustment is on that side, so it will always be 'tighter' and will have a little bit of rubbing, aka its normal. Does that sound right?

 

Alright, found hobbits site:
Self-adjusters
where he describes the drum self adjusters. From the look of that page and what hobbit did, my dealer is full of it. Each side should adjust independently, and right now my passenger rear brakes are too far out and are rubbing at one point in the 'rest' position. So it looks like if I dial the self adjuster back a turn or so, then get in the car and pump the brakes a few times, the brakes should then reset to a more correct 'rest' position that doesnt rub.

Great, I can handle that easy.
QUESTION: Hobbit mentions on his page that he removes 2 relays so that the system doesnt pressurize and shoot out the pistons from the brake cylinders....is this step necessary for adjusting the drum brakes? It seems to me that removing these relays and depressurizing the system would only be necessary when working on the front disks, but not the rear drums. If i understand how the brakes work, I shouldnt need to depressurize and remove the relays, I should be able to just pull the wheel and drum off, and while the drum is off, make sure NOT to depress the brake pedal (although engaging the ebrake is fine). Please correct me if im wrong, I plan on doing this lil adjustment in the morning and would prefer to be able to put it back together