Bilstein Damptronic B4 report - M135i F20 LCI

[jqvm]

I recently replaced the front OE dampers on my 2016 M135i with Bilstein B4 Damptronic VDC/EDC units.
Handling and stability is great on my local bumpy roads. Previous struts were leaking badly so I don’t really have a good before/after comparison to OE. I’ve gone from crashing, knocking and bouncing to controlled and firm, happy days!

I was aiming for a commuter friendly ride, not a track car, as we have a bunch of bumpy roads and speed humps around. I decided to stick with EDC for this reason.

Ride height is about 20-25mm higher both sides with the new strut pressure (with LHS 10mm higher than the right, as per factory). The front was fairly low previously, 30mm guard to tyre gap FR. I measured the new struts to be approx 10mm higher from the spring base to the clamp position, so some of this lift is from the strut body itself.
I haven’t had a good spirited drive yet but handling doesn’t seem too affected with the higher front end. I’ll replace the rear struts at some point which should balance it out and return it back to a raked stance.

Bilsteins were sourced from Demon-Tweeks UK, I saved around 30% from local Aussie prices, though Bilstein had a few months delay on stock. Great service and updates while they waited for stock. I saved another $2K on labour quotes too.
Parts BLS23-238916 & BLS23-238923

I grabbed new strut tops from FCP euro, though the old top bearings were still fine even at 150k km.

On the test drive, I got 50m down the road till my dash lit up like a Christmas tree! Dynamic stabilization disabled, front collision disabled… thankfully it cleared within about 1 minute. I had the battery disconnected for most of the install, but had to reconnect it to get a power window up at one point. I suspect this threw a few codes on the ECU that needed to refresh. Phew

Install tips:
Pass throughs - Recommend you get pass-through sockets if you can source them, especially for e18 strut piston nuts, 16mm sway bar. I ended up using vice-grips on a regular socket to allow me to counterhold through with a hex/torx bit. This was clumsy and didn’t allow me to get a torque wrench on.

Dropping the Hub - Theres a few youtube videos showing how to drop the strut from the hub pinch bolt. I mostly followed FaRKle0079’s F2x/3x video, I found that I didn’t need to remove the steering tie-rod arm from the hub (like in Speed Tweaks m135i video). With the control arms loosened at the chassis, the hub drops enough and the struts came out by turning the steering to full lock. The Bilsteins are a tad longer than OE but they went in ok.

Spreading the Hub clamp - I used an angled punch on the first side to spread the hub and get the strut out, this was a little clumsy but worked (Watch out to not damage the struts alignment pin thats inside the gap). For the second side I made a spreader tool with a piece of square steel rod, using a bench grinder to thin it down (10mm x 6mm, see photo). Or you just buy a spreader tool, but wheres the fun in that

Bilstein piston counterholds - The Bilsteins had a hex counterhold on one strut and torx on the other, a little strange. So just check you’ve got the right tools before you start loading up the spring compressor! The new 19mm nuts for the top of the piston came as nyloc’s, so I wasn’t too concerned with my strong arm torque guestimate on these.

EDC wiring - the Bilsteins came with new electrical cables for the dynamic damping. The connector is in a different orientation on the strut to OE so you have to use the new cable. Fitting it was easy, just need to remove the front plastic guard in the wheel well.