[gkamieneski]

Those of you with the space saver spare bolted down under your cargo floor, either the OEM configuration or your aftermarket arrangement, how about saving some of us some grief and measuring the location of the M8 nut hidden under the floor?

Maybe if you measure at a right angle from the sides and front/back of the cargo cavity, some of us will be able to find it with a magnet or probe and save cutting the floor material in error.

Thanks in advance.

[gkamieneski]

Hoping to use this type of fastener to secure the spare with it's inside facing upwards so that I can store items inside it. I would have it pass through a disk covering the wheel's opening.

[analemma]

Pop out the four rivets on sides(screws, T15 I think) and front(expanding) of the spare tire well and look about where you'd expect. It takes about two minutes. Measure from front and side to the screw hole. Use a stepped drill bit to punch a hole through the plastic. You can't feel the nut through the plastic well and the frame it is attached to is steel so a magnet won't help.

[gkamieneski]

Thanks, Analemma. I was able to reveal the screw receptor without a lot of difficulty.

Now my issue is that kind of screw is required. I thought the BMW thumbscrew was 8M, but I tried an 8M bolt and some 8M taps I had and although I believe 8M is most likely correct, I guess I am off on the pitch.

Hope someone out there has the specs?

[gkamieneski]

Guess I am looking for confirmation that the BMW thumbscrew is an M8, then I need to know whether it is 1.25, coarse or 1.0 fine pitch?

Anyone with a thread gauge or experienced eye?

[//TMT]

There is no way it would be fine threaded, if for no other reason than to be a huge chore to deal with spinning it on or off.

What's wrong with the M8 fastener in the threads? Does it not enter at all, or does it start, but then bind? I assume you checked for paint etc.

[gkamieneski]

Well, I bought the wrong "test" M8 bolt, having purchased the 1.0 pitch. I will go back an get a coarse, 1.25. I may have to chace the threads with a 1.25 M8 tap.

Confirmed with the star knob supplier that theirs are M8, coarse. Still need to figure out how long I want the threaded portion. I know the OE BMW thumbscrew is 68mm, but I won't be using the tray or cap cover.

[analemma]

I just asked my fastener store for an M8 machine screw to test, and it was vehard to screw in, but it never hung up. It seemed like there was some burr on the hole.
I think there's a thick layer of paint inside the nut. Part is this: Wing screw M8X68 1 07119908728. $10 and you know it fits. It's also plated to suppress corrosion. When I assembled I used a layer of lithium grease. The factory screw was still

[gkamieneski]

Went back and got a M8 bolt with coarse (1.25) thread and it threaded right into the receptor under the floor.

So, confirming that it is M8 1.25.

[MtnHank]

Here's a link to the wing screw> I have not ordered one yet. https://parts.bmwofsouthatlanta.com/...00-07119908728 I would like to know if they actually have it in stock.