Project E39 M5, Part 3: Installing and Adjusting KW V3s



Now let's start talking suspension settings and how to go about properly setting up your new adjustable shocks. Like we talked about in the beginning of this article, a comfortable ride is a very relative term. Being able to tweak the damping settings of your suspension is the only way to create that perfect ride for YOU. It's also a sure fire way to really screw things up. So let's get some basics out of the way before we start turning knobs. But first, an educational video:



Compression: This is the shock slowing down the upward movement of your suspension as it goes over a bump. It does this by regulating how quickly it displaces the fluid in the shock body. The compression or bump adjuster on the KW V3s adjusts how much the door that regulates the fluid's travel opens and closes. The less the door opens, the less amount of fluid that can move through the door, thus slowing down the speed of the shock's piston movement. So the more you close the door, the less fluid you're allowing to travel through the door, and slowing down how fast the piston moves. This slowing down of the piston is what creates a stiffer ride. 

Rebound: During the upward movement of your suspension kinetic energy is stored in the springs. This energy is released during the suspension's downward movement and is controlled by the rebound adjuster. There is another door that controls how quickly the fluid controlling the piston's speed and that is connected to the rebound adjuster.

With those two elements in our knowledge bag, we can start talking about how these elements come into play during our adjustment process. I'm no suspension guru, but I'm very lucky to have Sir Suspension himself, Mike Kojima, here at MotoIQ for insight on his best practices. So let's walk through what we feel is a proper basic adjustment process.

1. Set all your compression adjustments to full soft

2. If you are new at setting up two way adjustable shocks, set all your rebound adjustments to full soft. Or if you feel that your base settings are pretty good and you have a pretty good feel for setting up shocks,you can set the rebound adjusters at 50%, just make sure the percentages are the same all the way around. I say percentages, because some shocks don't have the same amount of adjustment increments. So the fronts can have 16 settings, while the rears only have 10.  In that case you would set the fronts at 8 clicks from full stiff and the rears at 5 clicks from full stif.  I just know that I prefer a sportier ride and Mike was helping me so I opted to start at 50% on all four corners.

3. On your initial test drive get a solid feel for how the front and rear react to a bump. Find a road you know has a couple of well spaced bumps. Try to stay away from really bumpy roads, the consecutive bumps will make it difficult to feel what the front and rear of the car are doing independently. You are feeling for how the car reacts on its initial reaction to a bump. Not what it is doing during consecutive bumps. Take some time and drive around your regular commute also. Add compression first. Keep adding compression until you think it's too stiff and then back off a click or two. You want to adjust the front and rears independently of each other until you feel they are reacting the same and are at your ride comfort level, but ensure they are set the same from left to right in adjustment.   

4. When adjusting your rebound settings you are looking to control the kinetic energy stored in the springs during the compression of the suspension. Proper rebound settings will allow your suspension to settle quickly after an initial bump without allowing the car to continue bouncing around. What we are trying to accomplish is to return the wheel back to the road as quickly as possible, but at a slow enough rate that it won't make the car feel unsettled. Rebound adjustments most definitely have a point of diminishing returns. Remember that by increasing rebound you are slowing the suspension's downward movement back to normal ride height. Slowing it down too much can prevent the suspension from going through its full range of motion. Imagine that when your car is at normal ride height you have two inches of suspension travel. If during a bump the suspension compresses 1.5 inches and the rebound adjustment is set too high, the suspension will not be allowed to return back to normal ride height fast enough and be ready to absorb the next bump. So in a consecutive bump situation, on the second bump the suspension will start at a lower ride height, and once again reduce the amount of available suspensions travel. This “jacking down” effect can cause the car to literally ride on the bump stomps due to the little amount of available suspension travel.  Overall, the general rule of thumb is to run the most compression and the least amount of rebound needed to do the job.


Project E39 M5 sporting what we feel is the perfect ride height. A good compromise between looks and functional suspension travel.

The procedure above is exactly the way we set up our M5 and it has yielded excellent results. All of our goals have not only been met, but have been exceeded. Some of the MotoIQ staffers are accustomed to this type of performance from KW, but this being my first set I can honestly say that I am thoroughly impressed and satisfied with the KW V3s. Especially for the price! The KW V3s for the E39 M5 can be had for about $2,700. That is a killer deal for a coilover kit that delivers this level of performance. If KW offers something for your car, there is no need to be gun shy on your purchase.

The M5 is by no means a “tossable” car, but the spring rates and damping levels on the KW V3s have given our M5 the perfect balance of handling prowess and ride comfort. Initial turn in is much more controlled and the way the car takes a set is very reassuring. Ride quality is expected to shift towards the stiffer side of things due to increased spring rates, but it is not unwelcomed…at all. It feels perfect! During the initial set-up process I was really able to feel the difference each adjustment made, which made it that much easier to get an understanding of how the adjustments affected the handling of the car. 

I'm really looking forward to clocking a good amount of miles on these KW V3s and I will report back on how they are holding up in a future article. Next time we will be tackling the aesthetics of our almost 16 year old project. Here's to hoping nothing breaks on the ultimate-wallet-draining-machine during the long term test period…




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