Suprmedic

Hi all,
First post! sold my 911 and bought a 2017 GLS 450 that I absolutely love. We bought t with around 50k miles on it and have driven about 5 K since. I noticed a noise that is prevalent around 45-75 mph. A kinda of crescendo decrescendo road noise that is louder at 70-75 than at lower speeds. There is no shaking or vibrations, handling not affected from what I can tell... My first thought was to rotate and balance the tires and get an alignment- then maybe take a look and see if the brakes may be an issue. Has anyone else had this type of issue?
Thanks!

chassis

When driving 70mph, lift off the throttle (gas) pedal. Does the noise change? Repeat this test several times and report the results.

Suprmedic

No, it continues when I let off the gas. Doesn't seem like it is coming from one side vs the other either. Thanks!!

chassis

The test if it was done carefully rules out driveline (propshaft) related problems.

Have you looked closely at the tires? Are the tires original or replacements? People on this site report 20k-30k tire life regularly. The GL/GLS platform has excessive, imo, alignment settings which cause inner edge tire wear. If your tires, particularly the rears, are worn, they could make noise or "sing" at higher speeds. Check the inner shoulders of all tires, carefully. Run your hands around the inner edges, carefully.

Suprmedic

Thanks again! It seems to be loudest around 70mph- if I let off the gas it is still there at that speed (if Im going down a hill) and as it drifts closer to 60 it quits down quite a bit. At 55 it is not heard at all.

Tires have about 3K miles on them, Michelin's. no noticeable wear. They were inflated to 35PSI and I raised them to 40 to see if that made them better/ worse and it really didn't make a difference.

chassis

Can you describe the noise?

Whistling
Humming
Drumming
Whining
Whirring
Screeching
Squeaking
Droning
Moaning

Suprmedic

Almost like a rubbing sound. low pitch like "zhuooo zhuooo zhuooo" LOL. The sound does change depending on the road surface so I think it has to be the tires.....

chassis

Agree, tires or brake rotor or brake pads. Less likely is a halfshaft (axle shaft) or wheel bearing.

Suprmedic

So, I have a set of winter tires on separate rims that I put on last week. The sound is still present. I took the car up to 80 and applied the brakes mildly till it hit 60 and the sound was present throughout that range- making me think that the brakes are a less likely culprit- there is no vibrations nor change in driving dynamics noted, ever, just he sound.

Likewise, I down shifted from 9th to 8th and the sound characteristic did not change.

By process of elimination I feel like this must be wheel bearings?

Again- the car sounds normal till 60, loudest around 65 with intermittent sound and the sound becomes more steady at around 72 or so.

Makes no sound at lower speeds- ever-

Crazy right?

chassis

Maybe wheel bearings, due to the continued noise with brake application and presence after wheel/tire change, and no change with throttle application.

Try driving when the noise is at the peak (65-70mph), with no cars around you, and safely swerve left and right smoothly, and somewhat aggressively, but do not jerk the car back and forth. LIke a slalom course. Does the sound change?

Suprmedic

Just a quick update on this- it ended up being the front left wheel bearing. Got it fixed a few months ago and have not had an issue since. Interestingly it was not the typical wheel bearing noise.... Thanks Chassis for the assist

Golfather

Good to know. Thanks for sharing.