History
Let’s face it: ground effects are cool and stock
e34’s, with the exception of repaints, M5’s, and model
year ’95 cars, just don’t have much going on for them
around the rockers besides some black underbody coating garbage
that would make the new pope weep.
After my three month long Style 5 acquisition fiasco, I finally
got a set of wheels and was about to leave well enough alone when
our friend Bret Luter informed us of an exciting opportunity.
As I confirmed, Style 5’s with a set of skirts look bangin’!
I bopped over to Bret’s farm and a few c-notes later, I
was the owner of a set of M-Tech skirts from a mangled ’95
525. Although mine came with a little damage, painting (or repainting)
a set of skirts should be a less-than-$100 affair. Lucky for me,
they were already green – just Oxford Green, not Fritz’s
current Islandgrun – so I’m leaving them alone for
right now. The Oxford is a slightly darker green, and the two-tone
effect that resulted is a nice variation on the US ///M5 color
scheme.
Buying these parts from the $tealer is EXPEN-SIVE! Don’t
believe me? Check the ETK. BMA can probably cut you a ~ $475 deal
on the skirts alone. The body-colored lower door trim,
black on non-skirted e34’s, costs about $50 a door. Additional
expenses include the mounting hardware, which are comprised of
a grommet and a pressure fastener (x8 on each side) as well as
two piece “compound” clips (x5 on each side) on the
underbody. Add the cost of paint and buying new becomes an expensive
proposition. So, it behooves one to hunt around for a junked ’95
or ///M5 if you’ve just gotta have them. Once they’re
on, though, the cool points are out the window.
Prep Work
The standard E34 ///M-Tech skirt setup is comprised of the following
hardware: (2) skirts – left and right side, and there’s
a difference, (2) front door body colored lower trim pieces, (2)
rear door body colored lower trim pieces – appear to be
the same on both sides, (10) compound/two piece black plastic
clips for securing the underbody side of the skirt – 5 per
side, (16) plastic grommets – 8 per side, (16) adjustable
plastic fasteners for said grommets – 8 per side.
Part Numbers:
Skirts: 51712230339 & 51712230340
Trim: Front - 51212230373 & 51212230374;
Rear - 51222230398
Clips: 51711938940
Grommets: 51131934160
Fasteners: 51711959929
Note: there may be other hardware that will be needed, such as
the fastener that goes on the rear fender (could just as easily
use a standard tappet screw) or the foam “gaskets”
that form a seal around the jack points. Be sure to check your
ETK software prior to attempting installation so that you know
you’ve got everything. If there’s one thing
that I know you *do not* need, it is the “drilling jig”:
it serves no other purpose, to my knowledge, than to mark drilling
points, easily and cheaply done with a red sharpie.
Necessary tools and materials
Installing the skirts doesn’t require much in the way of
tools and shop materials. Snapping the fasteners into the grommets
does take a bit of strength, especially if the holes aren’t
dead on, so bring your A game. Also, I decided to attack a few
underbody coating issues before I covered them up with the skirts,
so I included some tools and materials associated with those repairs:
- 10mm socket and an extension, for removing the fender bolts.
- Needle nose pliers (easily take apart the compound clips
with these)
- Water pump/channel lock pliers (for setting aforementioned
clips and bending the rocker lip back in place from bad jack
placement over the years.
- A good drill and a 1/4” bit (or slightly larger). Use
a Milwaukee Magnum Hole Shooter if one’s available. I’d
started with a pathetic 7.2v VersaPack B&D, not a good tool
for driving 16 holes through metal with a reasonably large bit,
and it quickly died.
- A red sharpie or other implement (that’s visible when
applied to the black underbody coating garbage) for marking
the hole points.
- Rags for cleaning stuff up.
- Sandpaper or a good angle die grinder with metal brush (for
removing rust).
- Underbody spray or hard black enamel paint/stabilizer (for
covering up repairs).
- Wax or some kind of desiccant to keep as much road and rain
water as possible out of the space between the rocker and the
skirt, and for under the door trims.
- A beer (I prefer a glass of Carlo Rossi’s finest vintage
2005 sangria – nothing as classy as CR while working on
a bimmer, except maybe Franzia) and a good CD to listen to while
you’re working.
The Install
-
First things first: used the needle nose
pliers to remove the black trim located on both front and
rear fenders. At this point, I addressed some rust issues:
the paint on the front of the pass front fender had deteriorated
due to tire sandblasting.
Clean dirt and address any rust issues before installing
skirt
- The old, black lower door trims can also be removed at this
point. Might as well get all the old (probably) nasty stuff
out first. I was installing used parts and didn’t have
enough confidence in myself to pull the old lower door trims
off before I had the skirt on. It’s a bit harder to fit
the lower trims once the skirt is in place, and having the new
lower trims on the doors will also help when setting the skirt.
- Depending on how well your car has been treated over the
years, some rocker panel lip R&R may be necessary. Given
the idiocy of my car’s PO, I knew I’d have to do
a little work straightening out things down there. If the lip
is smashed or bent outward, the skirt will likely not end up
flush against the rocker. I didn’t take any pictures of
the process, because every situation will be different. The
basic idea is to strong-arm the lip back to normal, remove and
treat any rust spots, and fix any areas that have lost the underbody
rubber coating. Also, if any of this work needs to be done,
be sure to do it the correct way the first time – once
the skirt is on, or even partially on, it’s a pain to
get it off again.
- Mark and drill holes in the rockers for the grommets. Yes,
it’s a frightening thing to think about. I held the skirt
up to the rocker, got it as close as possible to where it should
sit when installed, then used the red sharpie to mark the mounting
points (8 per side) based on where the plastic fasteners hit
the rockers. Check the marks twice: although
the fasteners have some horizontal leeway, there is little room
for error in vertical placement.
- Once you’ve got your marks, pull out the holeshooter
and have at it. I used a ¼” drill bit, but had
to make the holes slightly larger to accommodate the grommets,
so it might be wise to use a slightly larger bit from the get
go.
Use a good holeshooter, Milwaukee/Magnum variant
- Set and press a plastic grommet into each hole. The first
picture below is of the grommet itself, the second is with it
“set” – use the needle nose pliers to pinch
the two lobes.

Grommet clip that needs compressing in order to set
- A set grommet can be pressed into the previously drilled hole
(you may want to find something to help press it in –
I used the water pump pliers with good success):
- Once all grommets are in, things should look like this:
- The frontmost fender bolt (one of the two that secures the
fender to the body underneath the car) has to be removed. The
other bolt can stay – the skirt has a hole to clear it.
If applying a coat of wax or other desiccant to the rocker panel
area, now’s the time to do it.
- Line up the skirt and (really) press it on. It may take some
serious force to get some of those fasteners in the grommets.
On the pass side of my car, I’d misaligned two holes bad
enough that one fastener had to be omitted. They’ll set
with a satisfying POP. It’s okay to leave one or two fasteners
out if necessary – the other six or seven are more than
adequate for holding the skirt to the rocker.
- Once the skirt is set at the top, sink the previously removed
fender bolt, securing the skirt to the fender, and the fender
to the body.
- Each side requires five “compound” clips. These
clips secure the bottom of the skirt to the rocker lip. As mine
were used, I had to disassemble them using a pair of needle
nose pliers. I assume they come disassembled from the factory.
- There are five mounting points along the underbody side of
the skirt. Here’s one of them:
- Fit the skirt part of the clip….
- Then compress the rocker side of the clip in with a set of
water pump pliers:
- The clips should be snug (so that they can’t be moved
with a hand).
- Once all compound clips were installed, I stuck on the lower
door trims. It can also be done before installing the skirts.
Because I was using used lower door trims, I had to improvise
getting them on (new trims may be easier): I temporarily removed
part of the end of the trim and slid it onto the door, then
pressed the removed part back into place. You may also want
to sink a fastener in the rear fender, but I left that for another
day when I’ve removed the rear wheels.
- Stand back and admire your hard work. Looks good, doesn’t
it? Forget the car FEELING faster, I bet it actually GOES faster
:o)
Best, Whit
Article By Whit Lowell /
1990 535iA
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