The way the old pre-m Leicas and the russian rangefinders work is very different from the way modern cameras work.
On these old cameras, the shutter is made from two black fabric shutters that are shaped like a U. What sets the speed is the distance between the first shutter and the second. This is done by dropping a pin in the top of the roller which contains many holes. Change the selected hole, change the distance between the shutters and thus the shutter speed.
The thing is that since you're directly manipulating the rollers (hence the rotating speed dial when you trigger the camera), there is only so many positions in which the pin can be inserted. If you change the speed when it isn't wound, what happens is that the pin will shear when you wind the camera simply because it is attached to the second curtain and designed to be selected when the shutter curtain is to the right.