I'd bet that when it left the factory it had a regular standard 27.2 mm Campagnolo seat post .
The frame has probably suffered some ham-fisted tightening over the years , maybe with wrong-sized posts in it . This has probably deformed the seat lug .
And , we do know for certain that Schwinn used heavier walled TOP tubes , in the really large hand-made frames , like the 26-inch Super Sports . I've always wondered if they used special TOP tubes in the really large , 25-inch and/or 26-inch , Paramounts .
But I've seen a number of 25-inch Paramounts . They all used the standard 27.2 Campagnolo seat-posts .
Cheers Raoul Delmare Marysville Kansas U.S.A.
-------------- Original message from John Clay <jmedclay@yahoo.com>: --------------
> Thanks for the replies ya'll. It appears to take a
> 27.0 post so based on the info Mark provided I guess
> it's 1/.7 tubing.
>
> This frame was given to me when I was dumpster diving
> for old frames to cut up/repair for framebuilding
> practice. There was no headbadge. Neither the folks at
> the shop, nor I, had any idea what it was. It came
> awfully close to getting destroyed at my hands but the
> lugs, of which I knew nothing, kept my attention. It
> didn't make sense that a cheap chrome frame & fork
> would have fancy lugs and a Campy headset. That was
> the extent of my knowledge. A chance look at a Masi
> replica track bike photo (by Brian B.) with the same
> lugs, and a few emails, saved it.
>
> I think I'll build it up with spare parts and ride it
> a bit to see how the 1/.7 walled tubing feels. Then
> I'll trade it down the road a bit.
>
> John Clay
> Tallahassee, FL
>
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