In the last couple of weeks I've noticed a marked increase in the amount of noise coming from my rear tires - particularly between 45 and 65mph. If I go above 65mph (usually 70-75 mph) the sound decreases dramatically.

I'm afraid that this may be a bad rear wheel bearing. Anybody else agree based on my description?

I have a 4000S (FWD) and had my front wheel bearings replaced earlier this year. Nokian NRW tires.

a couple of the bearing were worn flat, replaced both sides no more noise.

Wheel bearing noise *usually* changes, depending on cornering load. If a bearing is bad, usually the 'outside' wheel when cornering will make more noise. And usually more noise in a corner, than driving straight (As that's when the bearing gets loaded up).

A good wheel bearing test is to jack the wheel up, and test for play (same as checking for a bad ball joint). Maybe give the wheel a spin as the same time as it's up in the air..

On the other hand, it *could* be tire noise. I've been tricked into thinking I've got a a bad bearing, only to find it's a tire. Maybe swap tires front to back, and see if the noise changes. Especially as they are sort of snow tires..

Good luck!

I had the tires rotated a few weeks ago. The noise didn't start immediately after the rotation - just in the past week or two.

not too hard to do.

...and do some fast lane changes. Left then right. If the sound get either louder or quiter, then it's most likely bearings.

I just did the rear on mine a week ago. Took me about 30 mins. very easy.

Yep, it was the inner and outer rear wheel bearings. Had it fixed by the pros. $60. Was in and out from diagnosis to being fixed in about 40 minutes. Totally quiet now.