Strange low pitch creaking sound in reverse

[sdrevik]

Just started today. Only happens in reverse. Car drives normally forward and high speed. It’s low pitch, not like a break squeal. Nothing seems caught in wheel well. Thoughts?

2018 M3. Aero covers are NOT on

 

[zhu-]

I had a similar problem when going in reverse in rainy or wet conditions. Service said it was a cracked brakepad from lack of use and was replaced under warranty. It might be that or a pebble got caught between the brake rotor and shield behind it.

 

[sdrevik]

I had a similar problem when going in reverse in rainy or wet conditions. Service said it was a cracked brakepad from lack of use and was replaced under warranty. It might be that or a pebble got caught between the brake rotor and shield behind it.

Mine was water related, but not the brakepad- drove through a deep puddle and it knocked one of the undercarriage shields partly off. $202 to repair, took < an hour.