Another addition, my car has 29k miles (46k km) - its a G30 540i with the 19in on summer tyres. Its in excellent condition (not driven hard, not powerslid, did 3 launch controls its whole life). The part fails naturally. The Guibo (or Flex Disc replacement) will solve 80-90% of the issue. The center bearing solves the rest.
The low hum (very low amplitude and frequency) is gone. I think the finding is the same as other people here in the forum.
Well guys,
I am from a Brazil and I stumbled upon this thread from bimmerpost.
My G30 540i had this issue, of a low rumble noise starting at 65kmh/40mph and going all the way to 115kmh/70mph
The noise would later get drowned out by the noise of the engine and wind noise. Using the topic as a basis, I requested my dealer to replace the flex disc and the center mount bearing of the driveshaft. This eliminated the noise. The low rumble noise was not accompanied by any vibration.
I also suspected of the reason the noise started was related to the driveshaft as I did a launch control before this started. The issue presents itself because of age (not mileage). Rubber components in the driveshaft get aged, and when stress (aka launch control or brake torquing) are presented, the part fails.
