So I have an Astro-Daimler SLE 531 frame as just frame and fork. No headset or bottom bracket.
I measured the the crown race seat as 26.8 and the inside tube as 30.8. I think my measurements are
accurate within a .1 mm. According to Sutherland's this is more or less correct (26.7/30.8) for Austrian frames.
On top of that they say the threading is 26mm x 1.0mm. Where the heck to you get an Austrian headset.
They only list Steyr-Puch as a maker of Austrian headsets. Do I follow Austrian ebay relentlessly? Or there
other sources? I know there a few A-D fans here. Seems like a problem that has been solved before.

EDIT:
After a little searching I did find this
https://www.bikeforums.net/bicycle-mechanics/336372-austrian-headset.html
But not super helpful.

I have a what I think is a 78 Austro Daimler SLE. It's dark navy blue and 531. I never knew the headset was anything special but if there is something I can measure on mine that will help just let me know.

Thanks for the offer. The other thread plus Sutherland's makes it clear I have a problem. Someone in the
other thread mentioned that his headtube seemed to be a standard size. I could replace the fork, but
I don't think I will have much luck with the 30.8 headtube size.

EDIT: Actually the headtube is 30mm so I might get away with just replacing the fork.
Sutherland's says the the pro models go with the Campy/Italian standard. That hasn't worked out so
far.

I had an A-D SLE (I think it was an '82) It had a standard 1" threaded headset. I think the austrian headset standard was for much cheaper bikes than your SLE. What year is yours? There's some A-D catalogs at:

https://bulgier.net/pics/bike/Catalogs/AustroDaimler/

The measurements are a bit confusing. Most high end European bikes had a 30.2 headtube. This
one is 30. The fork is definitely 26 instead of the common 25.4.

There is no chroming of the fork ends. Not sure how else to tell the year.

Serial number 6008681 or maybe 1863006 and
[]00279 plus a random E and F and [ on its side.

Would it make sense to thread the fork to 25.4?

This might suggest 77


https://www.classicrendezvous.com/Aus...al_numbers.htm

2 things come to mind: you should be able to get a good frame guy to mill the headtube ID to standard diameter, and if the steerer threading is really unique you can't simply re-thread (I don't think) but I haven't tried. Check with the good frame guy about that and consider either a replacement fork or splicing a new steerer (with ISO threading) onto the original fork (my choice).

This is a odd enough problem that this ebay listing includes this guarantee:
I just got around to verifying that the BB is English .

I have 2 A-Ds...a Vent Noir II (same vintage as the E-bay frame you reference), and an older A-D SL. The Vent Noir II is full 531 and takes a standard headset. The A-D SL is not 531 and has the Austrian headset (with English BB). The headset on the SL is nothing special, but has proven durable with the occasional overhaul (new bearings, etc.). So one option might be to keep an eye out for an inexpensive A-D S or SL (or comparable Puch model of the same era) and use the headset for your SLE.

Dig up a cheap Puch or A/D frame - should have that headset.

-Kurt

I have an old Ted Williams Free Spirit that had an Austrian headset. I switched the fork, used a standard headset (shimano 105), and shimmed it with a couple strips of cut up coke can.