Strut tube diameters

KenB · Post by **KenB** » Sun Jan 27, 2013 7:36 pm

Searched the archives but found inconclusive evidence.

Are there indeed multiple strut tube sizes for e12s? I ask because I have a 1979 528i (tubes presumed original to car) and bought a set of Bilstein sports (used) that the seller said were for an e12. When I tried to install these inserts into my tubes, they slid in there, but fit like a glove, so that there is no way any top retaining collar could ever squeeze in there as well. No way--not internally threaded, anyhow.

So, do I need "late style" tubes to fit these inserts into or did I just plain buy the wrong inserts?

Thanks for any info.

KenB

themilkguy · Post by **themilkguy** » Mon Jan 28, 2013 8:27 am

This post couldn't have come at a better time, KenB! I'm going to piggyback on it and try to learn something myself.

My '73 Euro 520 has the same strut insert part # as some Euro E3's, but no NA E12's, and just yesterday I was wondering if there were diameters/parameters people might know and if I could find an equivalent to fit my car.

Sorry, not trying to thread-jack.

Craig

Blaise · Post by **Blaise** » Mon Jan 28, 2013 2:00 pm

Hopefully this helps.

As far as I know, there are two front strut versions on the E12. The early version is up to 1976 and is the same as the bavaria. The internal specification on the bilstein shock differ (from what they told me), but externally, only the threaded nuts differ.

Here is the early version:

This was the stock strut on my 1977 530i (manufactured 9/76). I discovered this because I first ordered the later style shock and it would not engage the threads.

The whole strut assembly is interchangeable on the car.

The shock cartridge is a tight slip fit into the strut body, that is normal.

I plan to install some sports in my car to replace the heavy duties. Since I could not find sports in the early style thread, I will be installing later struts.

I am guessing that you have later struts and bought early shocks.

Hope this helps. I am no expert, just sharing my experience on the subject.

Southernboy · Post by **Southernboy** » Thu Jan 31, 2013 3:21 pm

I'm currently redoing the front suspension on my 75 525. Since I haven't gotten it back together yet, I went down to the garage and measured the diameter of my strut tubes. The ones on my car are 58mm across or 2.28 inches.
The ETK shows that from 72 to 4/76 there was one model for Bilstein, and then from 5/76 to 9/76 there was some sort of change and there was a different part for those months. I don't know what they changed, but it looks like there might have been then another change with the face lift in Sept 76.
Hope that helps someone,
Kevin

themilkguy · Post by **themilkguy** » Thu Jan 31, 2013 6:43 pm

Blaise and Kevin,

Helped me! Thanks for the insight.

Cheers

Blaise · Post by **Blaise** » Thu Jan 31, 2013 7:08 pm

themilkguy wrote:Blaise and Kevin,

Helped me! Thanks for the insight.

Cheers

No worries, that's why we are here.