[Alscoob]

My 2020 540i x-drive G31 is completely standard and has rear air suspension with front springs.

There are occasions when I have been out for a drive (me only in the car) and when returning home, switch off and after locking the car there is a buzzing hiss sound from the rear nearside. Just wondering if those with Rear air have noticed similar?

I have noticed when the car has had rear passengers in and they get out then the rear ride height is like a 4x4 but it does settle back down slowly shortly after locking.

Is my concern just a lesser symptom of this, although I would have thought that without any load changes it would be at a consistant ride height??

Any advice please?

[Chappers 71]

Yeah I can sometimes hear the air suspension pump priming the system when it wakes up or goes to sleep & that’s just normal if it’s the sound you’re hearing. Maybes post a vid clip & I’ll let you know if mine sounds the same.

As for the suspension I never have rear passengers, other than our two ‘puppies’ Frank & Bella but I haven’t noticed what you’re describing.
I suspect that as the active rides 10mm higher than non adaptive when you have the weight of rear passengers the system compensates by rising the suspension to account for the added weight & maybes that’s what you’re seeing….that’s just my thoughts but I’m not a suspension expert

[Alscoob]

Originally Posted by Chappers 71

Yeah I can sometimes hear the air suspension pump priming the system when it wakes up or goes to sleep & that’s just normal if it’s the sound you’re hearing. Maybes post a vid clip & I’ll let you know if mine sounds the same.

As for the suspension I never have rear passengers, other than our two ‘puppies’ Frank & Bella but I haven’t noticed what you’re describing.
I suspect that as the active rides 10mm higher than non adaptive when you have the weight of rear passengers the system compensates by rising the suspension to account for the added weight & maybes that’s what you’re seeing….that’s just my thoughts but I’m not a suspension expert

Thinking about it you likely right on the noise, after all if it's parked on anything thats not level when you start it up it needs to 'be awake' for when you drive off and guess when you switch off and it's on uneven ground it must have a set rest point. It's air suspension so if its putting more air in to keep it level for a certian situation it must have an escape valve to let air out as well when the situation changes.

I didn't know that adaptive was 10mm higher than non adaptive, I knew about the x-drive being taller than standard and M sport being 10mm lower than standard (from F3x days), so thats interesting.

I've spent a fair bit of time comparing 540i's looking at the ride heights and mine does look as if it's on stilts on level ground and often wondered why, so now I know....thanks.

It's due in this coming Friday for ACS springs front and level adapters rear so I'll get plenty of measurements on heights before and after so I can see what the overall lowering is. Hoping it's not too low but going by my last experience with ACS I would doubt it, anyway improved ride and handling is the objective, so we'll see.

I know you were considering the same, so if you're non adaptive you could be a further 10mm lower than I will be with ACS or maybe the springs are different for LCI. I'll send you the existing wheel centre to arch heights when I get them so you can check, then you can check with Lorcan about springs etc.

[Chappers 71]

Cheers, no worries
Mine also has adaptive suspension so it’ll be good to hear your thoughts on the ACS lowering kit