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      01-13-2013, 09:54 PM   #1
mike519
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Drives: 2018 M240i
Join Date: Apr 2012
Location: Waterloo, Ontario

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DIY: Magnetic Front License Plate Holder

Bought my M in November in the US and did not want to drill any holes in the front bumper to mount the front plate so it got me to thinking...

On Mirko's recommendation, I bought the Skene plate holder as others have done but, again, I did not want to drill holes even under the lip where others have mounted studs to screw the plate to. I also wanted it to be quicker on/off so the only real option was magnetics.

First problem...the Skene is aluminum. Now that I am done, if I knew where I was going to wind up, I would have custom made the whole bracket and saved $35 or so but starting with the Skene did make it a little easier.

Second problem...it had to be really strong. Of course, I don't want the plate falling off while cruising on the highway.

Other problems encountered will be discussed in the post...

So, step one is to modify the Skene lower arm and add a steel plate so that its magnetic (duh)...






I then Plastidipped the arms so that they wouldn't scratch the underside of the lip (pics later) then set about to find some good strong magnets for inside the bumper. I removed the bumper for easier installation and measured the inside lip. I settled on 2 inch long magnets based on the lip but realized I would have to cut out a bit of the lower grill lip that wraps around the lower bumper lip so that the long magnets would sit flat on top of the lip. I wasn't sure the strength of magnets that I would need but found a wide range of magnets (and a very helpful person via email) at kjmagnetics DOT com. I settled on their 2" X 1" X 1/2" N42 magnets ($26 each).

I found these magnets not quite strong enough so bought some others locally to stack on top (stacking increases magnetic pull). I bought some 1" round X 1/2" thick rounds and added one more on top of each bar. The following pic shows two on top but I found afterwards that only one was needed (will address this in a minute).



I used Metal 5 minute epoxy to attached them to the bumper then covered the whole thing with duct tape. Holds really well.

So, after trying out the brackets and plate setup, the mount held really well except for one thing. if there was pressure applied downwards on the plate itself, the mount would have a tendancy to "hinge"...it was like there was a hinge attached to the end of the bracket arms but the plate (front) would pivot downwards. I would assume it would still fall off if I, Say, hit a big pothole.

What I realized was that the top needed to be fixed by a magnet as well so that it would be able to "hinge" downwards (I know, getting confusing...stay with me). So, I measured the distance between the arms of the brackets when attached to the plate and cut a piece of 1" steel plate to join the tops of the two arms. I used 3/8" long 10-24 screws with really thin flat locking washers (the ones that look like gears) and nuts with blue Locktite on the threads. As an advice piece here, mount the plate on the bumper side of the brackets, bolt heads facing the bumper, and nut between the bracket and plate. Just use the slots on the Skene.

OK, pics for the above...






Now, in the above pic, you will notice a few things. First, I PlastiDipped the entire steel bar (and the previously mentioned lower bracket arms) AFTER I brazed a 1" steel washer to the bar. The reason for the washer is so that it would be the only part to touch the bumper as it was being attracted to the the bumper.

I took another one of the 1" X 1/2" round magnets and epoxyed it to the inside of the bumper between the grills at the right height to attract the washer above (had to dry fit first to determine the height for the magnet. I also used duct tape on that magnet as a backup.

Last step (not shown in the pics or video below) is that I bought some scrap 3M No Chip film from an installer for $10 (he sold me an 18x24 sheet) and I will be cutting out 2" circles of it to install where the washer will hit the bumper. I can always take the film off when I go to do some detailing and put a new one on. With this size sheet I can get years of replacement pieces.

So, final pics of the install show nothing visible...




(underside of the bumper lip)


This last pic shows the setup from above...only the PlastiDipped washer touching the bumper and it will be protected with the 3M...



It does look like more is touching the bumper, especially on the right but this is just some foam padding I added to the Skene bracket just in case it does come in contact at some point like being pushed.

Here is a short video (couldn't figure another way to get a video up here) that shows how easy it is to attach the plate. Trust me, when its on, its on there tight!



Hope I caught it all. I am really happy with the results, though its not the most cost effective way of mounting a license plate! Probably cost me $120 all in with the bracket. Again, without the Skene, you could figure out how to do it for $40 less.
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