When we sold NEW Messinger juvenile saddles, they were shipped with a stepped adapter seat post. The seat clamp was 1/2" and I believe the reduced post size was 7/16", seemed to be larger than 3/8"?
I have a restored small Taylor Trike. I need some air tires for it. They are single tube tires, just small versions of the style used on the early bicycles. My tires are smashed flat and harder than bricks. It's just a display piece, not a rider.
John