Hi Jim:
From what I've seen (and owned), I think the SP decal only became unique after the end of the old gold-colored "foil" decal era. I have a 60cm c-t Bottechia Pro. from about 1970, and it is SP (27.2 post wouldn't fit, and the frame weight and stiffness both scream "full-SP"). The Columbus decal on that frame is the foil one - same as an SL frame of that vintage as far as I can tell.
My 60cm c-t Medici Pro Strada, however, being newer, has what I understand to be the SP-specific decal: black lettering on a gold background. My circa 1980 Merckx had that decal as well. All-SP frames are really stiff, IMO. What a difference a tenth makes....
SL decals of that era are the familiar white lettering on a blue/gold two-tone background.
Of course, there is no guarantee that correct decals were always put on frames, and often builders would mix SL and SP anyways, for example using SP downtubes and chainstays with an otherwise SL set. Decals on those were probably most often the SL ones that came with the tubeset. Full-SP frames generally started at about 59 cm c-t or so IIRC (like you mentioned...).
Framebuilders: were there ever SP fork decals to match the frame decal? (I've never seen any...).
Cheers,
Greg "Antonio" Parker A2 MI USA
P.S. you can always weigh a frame and fork to see if it's SP - it will be about a half-pound heavier if it's SP vs. SL.... Should require a 27.0 post as well.
> Message: 9
> From: "Jim McCoin" <j.mccoin@attbi.com>
> To: <classicrendezvous@bikelist.org>
> Date: Sat, 14 Sep 2002 16:21:21 -0700
> Subject: [CR]Re: Bianchi's
>
> My apologies, when I was asking about the Specialissima, "Team Issue" =
> differences, I was referring to the 60's era bikes.
> I've always believed that SL tubing was used on frames up to about 58 or =
> 59 CM and that SP was normally used on the larger ones.
>
> I don't ever recall seeing a Columbus sticker that denoted one or the =
> other, needless to say I have not seen every Columbus decal. Short of =
> stripping the paint how would you know.
>
> I believe the answers are lost in the two or three changes of ownership =
> and marketing teams.
>
> Jim "I've always loved Celeste" McCoin
> Fremont Ca.