Difference between 72 and US 73 bumpers

[Bmachine]

I found a few threads on the subject but no definitive answers. I had a chance this weekend to compare the two side-by-side and take some pictures.
It looks like the shape of the bumper itself is the same. But there are two major differences in the brackets. First, the 73 not only uses the well-known hoop bracket but also gets rid of the 72 bracket in the process. Second the side bolts bracket sticks out further on the 73. This makes the 73 only usable with the hoop. It would take a lot of fabrication to rebuild its brackets to 72 shape and look.

 

[dave v. in nc]

I'm guessing that the only "easy"way to make 73 work on 72 would be to very carefully cut about a third of the hoop, and weld in a flat/straight piece of stock to copy the offset distance of the 72, then (again, carefully) measured holes to match holes, with pre-welded nuts on the inside to accept OEM-style fasteners. holes could be slightly over-sized, but nuts would need to be pretty exact)...does that make sense?

 

[teahead]

Thanks for the inspection and comparo pictures.

I see bumpers for sale (early type) all the time and hardly any mention whether it's a 68-72 or 73 (US) style.

 

[Ajay]

I found a few threads on the subject but no definitive answers. I had a chance this weekend to compare the two side-by-side and take some pictures.
It looks like the shape of the bumper itself is the same. But there are two major differences in the brackets. First, the 73 not only uses the well-known hoop bracket but also gets rid of the 72 bracket in the process. Second the side bolts bracket sticks out further on the 73. This makes the 73 only usable with the hoop. It would take a lot of fabrication to rebuild its brackets to 72 shape and look.

View attachment 66528

View attachment 66529 View attachment 66530

I am now wondering if this change in Bumper brackets was an internal BMW theme. On the 2002s (e10 or 114 as some call them), the early cars up to 73 use a rear bumper bracket that is pretty easy to install--2 bolts to the body and one bolt to the bumper, on ONLY the 1973 2002s they used a similar OVAL shaped rear bumper bracket almost identical to the oval bumper bracket in the 73 Bumper picture above....makes me wonder....did they have a change of design or designer in 72 to implement the 73 changes in the e9s and e10 rear bumper brackets?

 

[HB Chris]

1973 DOT requirements were for a 2 1/2 mph bumper, one year only. Ever notice the 73 911 Porsche with the bigger rubber bumper guards? Same requirement.

 

[Ajay]

I knew there was valid reason for this.

 

[Gary Knox]

I knew there was valid reason for this.

Might be stretching it to say the Highway Safety Administration had a valid reason!! - ha. But, BMW certainly did once the decree was established.

 

[lloyd]

The post heading distinguishes between years, but neglects to mention that the 73USA front bumpers received similar (not identical) treatment. This topic has been indirectly addressed before, e.g.: https://www.e9coupe.com/forum/threa...version-to-72-bumper.29554/page-2#post-235946 ; https://www.e9coupe.com/forum/threads/bumper-talk.19501/#post-139439 ; https://www.e9coupe.com/forum/threads/euro-spec-bumpers-for-1973-cs-us.2860/#post-15556

The '73 USA front bumpers, including E3 models, are placed further away from the body than earlier models. The two main supporting brackets employed for the '73 USA models were changed from the original "L" shapes into something more triangular shaped. These changes were intended to make the bumper, and the body it presumably protected, slightly less susceptible to minor impact.

Curiously, some sources describe the brackets as "spring clips" suggesting flexion. Perhaps that is a bit optimistic, or it is similar to single-use torque-to-yield bolts.

E3 diagram

More E3

'73 2002 front bumper bracket

 

[m_thompson]

While we are on the subject of '73 bumpers, I need a #7 for the right side, probably P/N 51121823442.

 

[Bmachine]

While we are on the subject of '73 bumpers, I need a #7 for the right side, probably P/N 51121823442.

You will have much better luck with this by posting a new thread into the classified/parts section.

 

[m_thompson]

You will have much better luck with this by posting a new thread into the classified/parts section.

I have many times over several years, and never found one.