Grüezi Axel,
welcome at Stridaforum 
Many thanks for your interesting and congenial message!
In advance, I’d like to tell you that I do not own Strida bikes older than the 5.0 version - that means all the following is not first hand experience and there will be also some speculation in it.
Unfortunately I’m not familiar with the old bottom steering joint, but I do not think that’s normal. I guess this part will be worn out, but I mean you could check that later.
Here’s the replacement btw: grabcad/strida-mk1-front-joint-bush-1
I really do not think so.
This is in my opinion the typical sign of a rear hinge issue!
(The more load on the pedals - the more crackling sound.)
That should be fixed as soon as possible, of course you’re right.
Could you please upload a close-up of that bolt?
Yes, that is also possible. But it is a very challenging task to replace that freewheel.
I think we will be able to verify that, a bit patience please.
You lucky one…nowadays you have just about 50 km to reach the Spezi…for me it is an about 750 km travel…
Last weekend I was in Friedrichshafen to meet an old friend from the Netherlands…primary target was to meet again after years - but the secondary target was his wish to ride my efneo Strida…
Kind regards,
Chris