For quite a while now - can't say exactly how long, I've been hearing a "hum", similar to the hum I've heard coming from the tires of trucks with aftermarket, off-road tires, but not nearly as loud. It starts coming on at around 40 mph. As I said, not too loud, but, I've owned this truck since I bought it new in 2007, so I know the noises my truck makes. It's not the tires - I'm running highway-biased Michelin LTX M/S tires that are very quiet. And they're fairly new - only about 20,000 miles on them. I suspect the front wheel bearings (I replaced both rear wheel bearings several months ago due to one of them wearing out, and being alerted to the failure by the axle seal on that side failing and allowing diff oil into the bearing housing where the wheel speed sensor is, and causing it to fail, illuminating the ABS/BRAKE warning lamps). Well, yesterday, while rotating the tires, I checked the bearings for play (grabbed wheel at 12:00 & 6:00 and tried to rock it) and I could not detect any play whatsoever. Couldn't really tell if there was noise or roughness by rotating the wheel, or the hub, once the wheels were off, because of the brakes scrubbing a bit. Anyway, it's time for a front brake job, and I was trying to decide whether to replace the front wheel bearings, or just let them ride for a bit longer. The truck is my daily driver. 222,500 miles. I drive it around town - not many out of town trips - usually we take the GF's 2018 Civic for road trips. Still, it's how I get to work. I don't have any experience with symptoms of wheel bearing failure, as this is the first vehicle I've had with this many miles. So, can the front wheel bearings have enough wear to warrant replacement even if they don't have noticeable play?