BMW 128i Spring and Damper Upgrade: What I Learned and Recommend
Swapping more enthusiast-centric suspension proved to be a wise move.
Suspension is a crucial component to having fun with cars, as it dictates so much in regards to a vehicle's grip, feel, braking, and more. That's why, less than two months and 1,500 miles into new-to-me 2011 BMW 128i ownership, I've swapped out its suspension in favor of some performance-inclined dampers and springs.
The Drive and its partners may earn a commission if you purchase a product through one of our links. Read more.
Another benefit of upgrading your car's suspension is that you can really get a lot of value for your money if you pick the right parts. Top-tier coilovers are big bucks, and cheap junky lowering springs often do more harm than good — but a proven, high-quality pairing of springs and dampers gets you to a great sweet spot between a meaningful performance increase without costing a fortune. And generally, your car shouldn't even have to sacrifice too much comfort with such a setup.
Sporty suspension mods are generally kosher with the law and won't fail you on inspection, too. Unless the car is slammed low enough to be a hazard to ant colonies.
Since I've been researching and working with cars for many years, I didn't have to do much searching to confirm my selection of parts. My E82 BMW swapped out its suspension in favor of some performance-inclined adjustable Koni Sport dampers and Eibach Pro-Kit springs. These Konis are affectionately referred to as Koni "yellows" among DIY tuners, to differentiate them from the Koni STR.T "orange" model which we'll discuss in another post. It seems like a lot of 128i track and autocross enthusiasts who aren't running coilovers really dig this route, so I figured it'd be perfect for me since I had similar driving-fun intentions.
One brilliant feature of the Koni yellows is adjustable rebound damping — they can ride softer or harsher depending on how they're adjusted. Set them stiffly for more control on track, loosen them up for daily driving. Koni also offers a solid warranty, and they're rebuildable by what seems like all shops that do such work, so this set could last me a long time. The Eibach Pro-Kit springs seem like a good balance between street comfort and performance, and again, fellow 1er owners really like them. I think they might've been produced locally here in Southern California (Corona, to be exact), so that's cool.
I bought the suspension set off of eBay just a few days after I took ownership of the car, while the California DMV was still inking the pink slip. When I finally went to swap everything, it turns out I was wise to do so because the factory equipment was pretty darn shot.
The bump stops resembled Kong Classic dog toys that were entombed with an ancient Egyptian pharaoh's loyal Saluki. The rear dampers weren't leaking fluid, but the rods refused to extend out after being pushed in. Perhaps they bled out long ago? Although, the ride didn't seem terrible, so who knows. The front upper mounts were also cashed, but they still retained gobs of factory-applied grease, which was applied in spring 2010 according to the dates on the factory dampers, possibly by someone named Fritz or Helmut.
Doing the swap was generally straightforward, but for a simpleton like me who’s used to econobox front MacPherson strut designs and twist-beam rear suspension, doing this job on a BMW 128i was an annoying pain.
Some videos on YouTube helped demonstrate the proper procedures for swapping both the front and rear suspension, but the learning curve was still steep. This was due to me having to unbolt and unplug a lot more stuff while working on the front end. Once I finished one side and moved on to the next, I was much quicker during the second go-around. Three cheers for learning! Though, I crushed an ABS sensor wire in the process, so three cheers for later triggering an ABS warning light and having to buy a new one for $32.
This was my first time swapping suspension on a rear-wheel-drive car, too. I know that's not exactly a notable milestone, but for me, it was a bit bizarre pulling everything out from underneath the front wheel arch and seeing empty space where I usually see a driveshaft hanging down. In fact, when I first reviewed the procedure for doing so, I caught myself thinking, "but wait, how do you disconnect the driveshaft?" I'm only sharing this in hopes that perhaps someone has thought the same mildly embarrassing thing.
One big lesson I learned through this process is how every nut and bolt of the 1's suspension is logically laid out. While I was re-installing all of the fresh hardware, I never took more than a second to figure out which nut or bolt went where.
I also greatly benefitted from pre-assembling the new front damper and spring combos with all-new mounts, rubber isolators, and bump stops. Not only did they all need replacing, but it cut down the process of removing and reinstalling the front suspension by at least an hour combined. Because I didn't have a workbench and vise to do the pre-assembling, it took me about an hour to properly align everything safely and properly.
In addition to installing all-new dampers and springs, I also threw on Dinan camber plates to gain more negative camber. For context, negative camber is when the top of the wheels are tilted more inward. This allows for better wheel and tire clearance, as well as better grip and turn-in on track.
To properly install these, I had to cut off the guide pins on the top of the new OE mounts, which were formed there from the factory. My beloved Harbor Freight rotary tool, which has provided years of fateful in-a-pinch service, came through in the clutch like Brian Scalabrine in the fourth quarter of an early 2010s Bulls game. The mild cutting wheel attachment made short work of the mount's thin aluminum.
Moving toward the business end, the 128i's rear suspension was brilliantly easy to swap. I even exclaimed with glee to my neighbor mid-process that it was joyously easier than swapping the front suspension. And that is where I truly messed up.
As soon as I said that out loud, a higher power looked down at me, pointed, and said "Haha, you dumb bastard." Maybe it's because I was tired, maybe it's because I uttered such a statement out loud, but I could not for the life of me get the rear independent suspension lined up to thread in the final 18-mm bolt and button everything back up. I was fiddling with the jack for far longer than I care to share before I figured out that I could just grab a flathead screwdriver to manipulate the other end of the bushing to help finagle the bolt all the way through. Even better, this happened on the second side, after quickly completing the first without any finagling.
But goddammit, I got it. After reinstalling the wheels, safely lowering the 1er back down to Earth, properly torquing the wheel bolts, and taking it for a test drive, everything felt great. I still have to reinstall one of the trunk’s sound deadening panels, randomly one of the most annoying points of the job, but I might keep them removed until the aches and pains from performing this herculean suspension job subside.
The ride height difference is subtle, which was desired here.
Now that the 128i's fresh new suspension is all buttoned and ready to enjoy, up next will be getting it properly aligned. Not just because you should always do so after swapping suspension components, but also to give it a more performance-oriented alignment for better on-track fun and grip.
MORE TO READ
How Roll Center Affects Your Car’s Dynamics
Before you lower your car in the name of cornering, learn what roll center is.
How I’m Setting Up My BMW 128i for the Track
Understeer sucks. But now I know what needs fixing.