[DavyNM]

my two cars are the X1 with m sport suspension with 18 inch all season tires and the 330i with standard suspension and 19 inch all season tires. They were both built within the same calendar year.

while I've always realized that they were very different cars with different suspension setup, I had no quantifiable way of making a subjective comparison, until recently. I'm fortunate enough not to encounter speed bumps anywhere in my town. However, my local Home Depot just put up a few of them in front of the entrance. They allowed me present my case. The speed bumps are the same as the ones in the photo below.

If I drive my 330i, I can easily drive over those speed bumps at around 30mph without feeling any discomfort. Even my coffee mug in the cupholder does not spill a single drop. The suspension sounded like it was driving over a big sponge cake. Parking lot was empty because the Home Depot was already closed when I tested this last night.

Unfortunately, I also tried driving over those same speed bumps in my X1 with m sport suspension. Even if I drive over them at 5mph or less, the whole car felt like I just hit a concrete parking curb or someone is hitting the front end with a sledge hammer. I basically have to slow down to walking speed and slowly crawl over those speed bumps. It also sounded like the car crashed into something hard at 50mph.(like hitting a pothole on the highway)

yes, the tire pressure in both cars were at the recommended psi level. The weather was in the 70s.

is there any chance that the suspension parts in my X1 were installed incorrectly at the factory or have some sort of defect to cause such harshness? my guess is probably not because I literally just had the alignment done for the X1 at the BMW dealer last month and the tech said nothing.