I think the thin cups were originally Gran Sport or old Record, while the NR used thick cups. It may be the newer GS and Nuovo Gran Sport cranks continued to use thin cups. AFAIK all classic Campy triple BB's used thin cups. A trick Bill Ward taught me is that an axle made for thin cups will work with thick cups and vice versa. Usually you don't want to do this, but it can allow the same axle to work for either French/English or Italian depending which cups you combine it with.
Regards,
Jerry Noos
Big Spring, Texas, USA
> From: accobra <accobra@peoplepc.com>
\r?\n> Subject: [CR] Campagnolo Thin Cup vs Thick Cup Bottom Bracket
\r?\n> To: classicrendezvous@bikelist.org
\r?\n> Date: Thursday, April 16, 2009, 9:09 AM
\r?\n> Here's an easy question for someone out there, though I
\r?\n> suspect I'm not the only one that's been caught
\r?\n> off-guard so maybe this question will help others too.
\r?\n>
\r?\n> Back in the 70's I'd installed a sealed bearing
\r?\n> bottom bracket set-up (unmarked, maybe Edco?) in my 1975
\r?\n> Masi Gran Criterium & chunked the original Campy BB.
\r?\n> I'd completely forgotten about doing this until
\r?\n> recently. I wanted to go back to original specs so I bought
\r?\n> a replacement Campy BB set-up. But, I was having trouble
\r?\n> getting everything assembled. The spindle appeared to be too
\r?\n> narrow causing me to just barely run out of thread to
\r?\n> install the lock ring on the adjustable cup. The spindle
\r?\n> was correctly marked for a 70mm Italian BB shell and of
\r?\n> course both cups were marked for Italian thread. I started
\r?\n> looking at the cups and come to find out, the fixed cup I
\r?\n> installed was a "thin cup". I subsequently
\r?\n> installed a "thick cup" I had on-hand and now all
\r?\n> is well. About 2mm difference.
\r?\n>
\r?\n> My question is why do two different width cups exist (thin
\r?\n> cups & thick cups)? Is the thin cup simply an earlier
\r?\n> version? From what time period and for what use? Is it
\r?\n> just the fixed cup that appears in two varieties or is there
\r?\n> supposed to be a matching "thin" adjustible cup?
\r?\n>
\r?\n> I haven't had to mess with the fixed cups on my bikes
\r?\n> very much over the years so this experience was a new one
\r?\n> for me (and VERY frustrating until I figured out what was
\r?\n> going on!). Can someone shed some light on this thin
\r?\n> cup/thick cup subject? Thanks
\r?\n>
\r?\n> Mark Winkelman
\r?\n> Dallas, Texas USA