Metallic chafing noise from front

[ageevt]

Today I was driving along when suddenly there was a moderately loud metallic chafing noise from the front of the car. It changed in pitch as the speed of the car changed. I deliberately braked hard to use the disc brakes and it made no difference as the noise restarted when I sped up. There was nothing stuck underneath the car, as far as I could see. When I stopped, switched the car off (into Park) and on again the noise disappeared and did not recur during the journey, nor in the next journey. Any suggestions ? 2019 94 Ah REX.

 

[Arm]

Sounds like the cooling system...it ramps up as you drive faster so as to cool/heat the battery pack. Once optimal temperature is reached, it throttles back to a low steady state level. That's my guess anyway.

 

[mojo]

It's not unusual on the i3 for stones to get trapped between the brake disk and either the calliper mount or the rear shield, which causes a scraping noise. It happened to the previous owner of my car several times (he has a gravel driveway) and the disk shields are a bit bent where he physically had to lever the stone out each time.

Smaller stones may work their way out after a while, but unfortunately they do cause scoring damage to the disk - clearly visible on my car.

 

[MagicCarpet]

almost certainly stones stuck against the brake disc and shield, per mojo's post.
carry wooden chopsticks can usually see the problem and release by pushing the shield plate back by poking through the wheel spokes

happened to me 4 times and 3 of those in the first month