There was a functional difference to Campy cranks around 1978 - that is the year because of CPSC they changed the gap between arm and spider and there was a need for the longer spindle. The early cranks have the bigger buldge on the backside of the drive arm. Non-drive should be unchanged. So matching date codes around this time is logical and something I look for on a bike that is correct. Not necessary - but but something that one should try to do if they care about those extra silly restoration brownie points.
And the argument that Campy didn't do it?My guess is that Campy almost never mixed arms with different date codes. Most likely happened at the distributor or shop level. Considering all the arms I've seen over the years in fresh boxes that weren't messed with, they all in my mind had correct date code matches. And every NOS bike that I've had through my hands has had matching arms as well. I've seen bikes from the factory (I think) with incorrect cranks (i.e early) for CPSC front deraillieurs they came with, but date codes always matched.
Does this mean its always correct and Campy never did it? No - but its not likely.
Mike Kone in Boulder CO
> Hi Phil,
\r?\n> The "mismatched" date codes, one or even two years apart, where not and are
\r?\n> not uncommon. That is how they shipped from the factory. Campagnolo didn't
\r?\n> think that it was important. I suspect that whatever was in the correct size
\r?\n> bin at the factory was boxed and that is the way it was sent out to the
\r?\n> importers, and OEM's I have had many many Campy cranks pass through my hands
\r?\n> over the last 36 years both on and off bikes and the chance of getting
\r?\n> different date codes is just as great as getting the same date code on any
\r?\n> given set of cranks. I would hate to see that number stamp take on more
\r?\n> importance than Campagnolo thought it should have. Use the cranks you have
\r?\n> particularly if they are original to the bike.
\r?\n> Al Van Varick
\r?\n>
\r?\n>
\r?\n>
\r?\n> -----Original Message-----
\r?\n> From: Phil Sieg [mailto:triodelover@comcast.net]
\r?\n> Sent: Saturday, August 12, 2006 2:01 PM
\r?\n> To: Classic Rendezvous
\r?\n> Subject: [CR]WTB/WTT: Super Record brake lever and NR/SR crank(s)
\r?\n>
\r?\n>
\r?\n> Would like to buy or trade for a complete SR brake lever. I need the
\r?\n> earlier version with the vertical CAMPAGNOLO block-lettered logo. Needs
\r?\n> to near mint condition or able to be brought up to same with a little
\r?\n> elbow grease and Simichrome. It's going on a Joe Bell-restored Colnago
\r?\n> Super. If you have a pair and don't wish to split them up, I'm willing
\r?\n> to take both.
\r?\n>
\r?\n> I also have a set of NR/SR cranks with mismatched date codes. The right
\r?\n> is a '79 and the left is a '78. Since the frame is a '79, I'm guessing
\r?\n> that whoever assembled this in the shop for the customer just grabbed
\r?\n> what was in the box and ran with it. Anyone with similar mismatch, I'd
\r?\n> like to work a trade. If you've got an orphaned single crank (either
\r?\n> side), let's talk. Don't need rings, bolts, or dust caps. Just the
\r?\n> crank arms.
\r?\n>
\r?\n> TIA.
\r?\n>
\r?\n> --
\r?\n> Phil Sieg
\r?\n> Knoxville, Tennessee