Actually, S speed rating means 180 km/h or 112 MPH, and that is, as we would say, "crazy fast" to be driving in anything other than the most optimal conditions; that would be an empty autobahn with no traffic, dry conditions, during the day. Very few places where that can happen anymore.
So, you are saying that if you get pulled over by the police in Germany (no matter what for), and the police look at the speed ratings of your tires, they will then go to a database of 50 year old cars, and see that it once carried H rated tires, they will prevent you from driving away?
...and the Europeans have long lamented about crazy American automotive rules...
Yes, it is a bit crazy, and I would not go that fast either. But because the car is actually able to go that fast, the tires have to match this speed.
It's all about conformity, and as I understand it this is not only about tires, but basically all parts on the car. if a spare part is not meant for the car originally and/or manufactured by other suppliers than Mercedes, then the part has to have a certificate of conformity, typically from the German TÜV to be street legal. Your insurance could also be an issue, if you use parts which are not "legal" for the car.
I actually think it is the same rules all over the EU, but as far as I know, only the Germans are really enforcing them on classic cars. Here in Denmark they are not enforced with the same rigor. But basically yes, if you are stopped by the police or you go for your regular safety inspection, and you do not have at least H-rated tires on your Pagoda, you will be in trouble.
This is also why the German Pagoda clubs have actually asked Bockley to come up with a H-rated and cheaper white stripe alternative to the Michelins, Vredesteins etc.. Thus, as I understand it, the Bockley 185R14 tyre was developed due to this request from the German Pagoda clubs/sections.
But maybe some of our German members on the Forum can confirm this and give more details?
Cheers,
Christian