Droning noise left rear
 

I have a 2001 Boxster S. A couple months ago I noticed a slight droning sound from the left rear - most noticeable at steady highway speeds. There has been no increase in vibration. I had the car into an indy shop for the 60K service and mentioned it, but of course they said they didn't hear it. Since then the volume of the droning has been slowly increasing. My initial thought was wheel bearing, but If a wheel bearing was going I would expect it to get louder, faster.
Any suggestions/similar experiences?

Wheel bearings can make noise for a very long time. How many miles have passed since you first noticed it?

Maybe 1,500 miles. The droning noise level has gone from just barely and intermittently noticeable to louder and noticeable all the time, but not obviously LOUD, if that makes any sense

Yeah, with only 1500 miles I think the bearing is a prime suspect. The hard part is determining which one. You can try lifting it just enough so the tires are off the ground, grab the tire at the 12 and 6 o'clock positions and push back and forth and see if there's any play.

You may have to let it get worse before you can tell.

It could also be tire noise. Check the tires for unusual wear, especially scalloping.

Also check your parking brake cable is not rubbing on your wheel.

My 2000 Boxster S (67,000 miles) has also developed what sounds like tire noise coming from the back when going over 45 MPH. I can't tell which side it is coming from yet. Based on the other posts, it sounds like it might be a wheel bearing issue.

I'm planning a ~500 mile trip this weekend and was wondering if there's an issue with continuing to drive it. My understanding is wheel bearings typically don't catastrophically fail but rather just get louder over time. Is that your understanding as well?

Jack the car up and spin the wheels. Also try to push and pull the top of the wheel when off the ground. If there is any roughness in spinning or play in the wheel you have bad bearings.

A good way to check whether its a bad wheel bearing is also to drive the car through S curves and notice if the sound changes. If it does, its most probably a wheel bearing.

Also check you tires. If there's any scalloping you will have serious tire noise.