It seems your tires are rubbing the inside wall. Did you reset the compressor after changing the air bag? It is possible that the car is not rising and the 20" wheels will definitely rub against the wall and the airbag itself. I wouldn't drive the car before checking this. If you continue driving you'll risk puncturing the airbag. If the compressor works then make sure no air is escaping from the airline that is attached to the top of the airbag, and finally check both front leveling sensors...one/both could be out of place or broken off. Good luck.

BMW X5 4.8iS 2005

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BMW X5 E53, 4.8iS - 2005
Professional Stereo/Nav with DSP (modified BM54 module) - Converted to Eonon GA5166X with Reverse cam
4-Corner Air Suspension - Converted to BC Coilovers