Adjusting a Bilstein Suspension on an E39 M5

About a week ago I finally adjusted the Bilstein PSS9 suspension on my 2002 E39 M5. As I wrote back in April, the car came with this very expensive and desirable modification when I purchased it. It also came with a Rogue short shift kit, Dinan exhaust and some nice cosmetic mods like sensible grade window tint, M pedal kit and a sweet iPod integration. There’s nothing like buying from an enthusiast with deep pockets who added quality touches to your car, before you ever saw it.

The Bilstein kit is a fantastic suspension, but the previous owner had set the car way too low IMO. It made the car ride in a hard, unsettled manner and I didn’t want the “slammed” look for my M5. The PSS9 kit is adjustable for both spring height and shock setting, but I could not find clear instructions on how to do it online. Finally after combing the forums (thanks Matt) and some time talking to Bruce at BavAuto and Keith at Bilstein US (both very generous with their time), I felt ready to tackle the adjustment.

After getting the car up on a lift and taking the wheels off, it was actually very straightforward. The shocks settings go from one through nine via a small knob at the bottom of the shock,with one being the firmest setting and nine the softest. They were set to six, which suggested it was the car’s height, not the dampening setting on the shocks, that was causing the rough ride.

The springs are adjusted by turning the collars with spanner wrenches that come with the kit. You turn the top collar counter-clockwise to raise it, clockwise to lower. You tighten the lower bracket to lock into place when you’re done. It takes some time, especially if you are raising the car and compressing the spring.

For obvious reasons it’s very important to adjust the springs the same amount on both sides of the car. It’s OK for the front and back not to match, and in fact some guys like the back up higher than the front, which gives it a look referred to as the “rake” of the car.

I set the spring collars at four inches, as measured from the first groove at the bottom of the shocks.  I also set the shock dampening at seven, a number which actually isn’t on the dial but I just did halfway between six and eight. I like the result so far — still a very firm ride, but the car feels more settled and smoother at highway speeds.

Of course, if you have this kit and are looking to adjust it use these numbers for comparison only, do your own careful measuring, YMMV, etc. and so forth. I now have 14 inches of clearance from the center cap of the wheel to the fender, which looks a lot more stock. It’s about the same clearance my M3 has with its stock M suspension, and  I’m told 14 inches is the clearance Dinan recommends for the E39 M5.

I’m glad to have this done. As much as I’ve enjoyed the car to date, it feels more like my car now that I’ve decided on the suspension settings, not a previous owner. I may have to tweak it again, or have the car professionally aligned. But as I said, so far so good and the difference in the ride is substantial.

A big thank you to my friends at Hollin Hall Automotive, who put the car up in the air for me. Without that, there would have been no suspension project. If you live anywhere near Alexandria, VA, check them out for your automotive needs.