I just recently purchased a 05 g35 coupe (46k miles) and have since then switched from my stock 17" tires to the rays 19" tires with NO problems at all. Last weekend I switched from the rays 19" to the G37 19" and now there's a slight rattle when I drive the car. It almost sounds like there's hamsters running around behind my steering wheel or near the dash. It's not LOUD, but it's noticeable when I have the radio off. Is there anyway it could be from the following things?

-The tires on the G37 rims are used. I doubt that's what's causing the noise, but who knows.
-I think I need another alignment. I feel my steering wheel moving to the right a little bit when I drive (it didn't make the noise when I had the rays on, and yes after I got the rays I got my car aligned. I did not get the car aligned after I put the G37's on).
-I have wheel spacers (20mm front, 25mm back)
-or is my car just old lol?

 

Larger rims mean less tire, which equates to more "feel" of the road and road noise, thus increasing bumpiness and the chance of rattles. I have one somewhere in my upper display that bugs the crap out of me when I don't have my stereo up. If your wheels are weighted properly, your best bet is to find where the rattle is coming from and get rid of it properly, like with dynamat or sound deadening material.

 

Hmm I suppose I never looked at it that way. The tires I had on the 19" rays where all basically brand new, but the tires I currently have on my new 19" rims are pretty worn. Thanks for the info man.

 

Check if the wheels are balanced and does it have uneven wear. That can transfer the vibrations to the steering column and wheel.

 

check the sun glass holder, my dash were making rattling noise coming from the dash, so i took mine to the dealer, found out it was my sun glass holder LOL. but i had fun with their rental car EX35.