[cdavenport]

That spring arrangement went on to further development & use on future Harleys. You see it quite a bit in the rigid frame designs. Until they came up with softails and smoother suspensions, that spring design was the most effective way to isolate the rider from shock.

It's actually quite ingenious when you think about it. The seat is suspended between two spring systems. Though it floats somewhat freely, it is still locked into place.