Well I've the same question that Ken asked.
I'm assuming that the clamp size on Cinelli steel stems were 25.4mm and the aluminum stems before ~1990 are 26.4mm. Since I'm looking for a 100mm steel track stem, I asked if there was different sizes of the steel.
Hilary's auction http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=717743733 doesn't list the clamp size, but this one does at 26.4mm (?) <http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1863839516>.
BTW, it's looking like I'll have to stick the badge I have on a non-badge stem, simply because there's none available. I'll be using Nitto B125 bars from Business Cycles http://www.businesscycles.com/trcomp.htm#navigation and Nitto uses 25.4mm on their track bars and stems.
Roy "fledgling trackie" Drinkwater Lititz "looks like the rain in Spain", PA
Ken Wood wrote:
>1. Has the Cinelli standard clamp size always been 26.4? I have an
>old logo 1A that appears to have a smaller clamp size. The stem
>came on an old Peugeot track bike with a Sakae bars that have a
>clamp diameter of approximately 25 cm (likely 25.2) with my
>inexpensive calipers. Could the odd size stem clamp be a French
>thing?