About 15,000 miles ago, I replaced the original tires on my 2001 Forester with Yokohama Avid Tourings. I've been pleased with their ride, particularly on wet roads. But lately I've noticed a distinct humming sound from the tires that I don't think was there before. A frequent passenger of mine also noticed it on his own. It almost sounds that the tire pressure is too low, but I don't think that's the case. The tires have been rotated every 5000 miles and I checked the pressure. It's up to the recommended pressure indicated on the plate on the driver's door of the Forester - 29 lbs.
Do the recommended pressures indicated on that plate pertain only to the original tires? If so, how do I find out the recommended pressure for the Yohohamas?
Any thoughts on that humming sound from Avid Touring owners?
Thanks!