Grinding/Crunching Sound from front axle

[trentr98]

Recently I've developed a fairly mild grinding/crunching sound coming from the front axle and was wondering if anyone else has even encountered this. At first I thought something was stuck in the brakes but a recent pad and rotor swap didn't fix it. I then thought it was my almost-worn summer tires but switching to winter tires didn't fix it.

I also definitely hear humming that I was thinking could be a wheel bearing, but there's zero play. Could it still be a bad wheel bearing without any play?

The crunching/grinding is mild and can only be heard at low speeds if you listen for it, and the wheel bearing type sound increases significantly with speed.

Appreciate any input!

*Car is a 2018 S5 Sportback and the sounds developed a few months ago.

[Z06Corey]

Crunching sound get worse if you cut the wheel hard (low speed)?

[IamRacer X]

Here is my experience with my RS5 SB. I purchased my RS5 new in Sept '19. Before the end of 19 I added wheel spacers to the car for obvious reasons. I only drive the car about 5-6K miles a year. Last year early in the year, the car developed a "grinding' sound at sharp turns. It seemed only to get worse over the next month. I figured it was a wheel bearing issue.
I decided to pull off my spacers and take it into the dealer for potential warranty repair. As I took my front wheels off I found the front hub bolts were VERY rusty. I hit them with some anti-corrosion penetrating spray and let it soak for a bit. I came back and scrubbed them with a strong brush. I cleaned them off as well as I could. I then removed the spacers and put the wheels back on. THE GRINDING NOISE WAS COMPLETELY GONE. I left it that way for a few weeks and the car was fine. The noise was gone. I decided to put the spacers back on and the car has been fine since. It is my belief there is either a design flaw or cheap materials used on the hub bolts. I plan to clean them up periodically going forward.
If you didnt notice them when the brakes were done, check it again to be sure.

[VVG]

It could definitely be the wheel bearings, even with no play whatsoever. This may be especially true if you are running wheel spacers or wheels with an offset more than a few mm different from stock.

[sammo]

Damaged CV joints or front diff from holding revs too long when using launch control?

[trentr98]

Appreciate all the help with this, and wanted to tie a bow on this. Ultimately ended up taking it to the dealership and it was a wheel bearing. these guys milked my Maxcare warranty to the max and billed a hair under $1k for labor but it is what it is, thank you all!

For anyone out there trying to diagnose a potentially bad wheel bearing, VVG is absolutely correct in that they can go bad with zero play.

[okie21]

Glad you got it fixed. I had an S3 with a bad right rear wheel bearing. The tire/wheel had no play, but I was sure it was bad based on the sound it made and it got louder when turning to the left. It wasn't until I had the hub/bearing removed and in my hand when I could hear and feel the grinding when I spun it.

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