Campagnolo Bottom Bracket Spindle Secret Decoder Ring?
 

Since you are working on a 1970 Italian bike, and assuming cranks are not marked or 7 or lower digit in a diamond, 70-SS-120. Is your spindle. This also assumes r-i-f-l-ed cups. If you have later cranks then you need the longer spindle, approx 115 mm. If you have 7 dated cranks you are going to have to look at the backside as this was the transition year for the CPSC modifications.

70SS or 68SS is the 126 era markings. Way back we had to live with the 120 spindles or order one with +1.5 for the chainline adjustment. Few distributors carried those and they were expensive even back then.
I don't know what the B suffix denotes, never ran across one.
The Z series spindles... Take you choice of urban legend, denoted the bottom brackets marked "extra precision" my liberal translation as I did find or just a mfg. code as Campagnolo USA had stated at one time, if I recall it was in one of their technical newsletters.

Regarding French threadings, I found that the stock moved slower through the distribution channels, record bottom brackets were being shipped long after Nuevo record brackets were seen in the other threadings

The "Z" is a manufacturing mark and means nothing.

This link will take you to some "official" Campagnolo bottom bracket info. I have it in pdf also if you want to PM me your email address. I thought it was already on VeloBase but did not see it. I will check with Jon about getting the pdf added.

I always liked this chart (though some of Sutherland's info is more accurate).

Campagnolo bottom bracket info

Note that Gran Sport or Record thin cup spindles are marked the same as the thick cup Nuovo Record spindles, so you need to check the inner bearing journal to journal distance to determine what you've got.

I use a 68-SS-120 thick cup BB (1973 NR) on my 1973 Raleigh with 126mm spacing, and it seems to be just fine. If I take a steel rule and place it between the chainrings, it hits the 6 speed rear right between the 3-4 cogs. Same with sighting it. I guess 1mm off might be hard to see however.

Thanks for the Campagnolo tech article reference. I have it around here somewhere. I completely forgot about that.

Yes, I know the 70-SS-120 double with NR (r-i-f-l-e-d) cups will work for my Atala.

Lynn, it's just not clear.

What is the source for that info? It seems like it isn't actually from Campy, since the pages do not identify as from Campagnolo (sorry, I do not know what Record News was). And if you put the word "official" in quotations, it is not clear if you're saying it's dependable or it isn't.

Sorry to be so nit-picky, but if it's actually information released by Campagnolo, something should say it clearly, since that means you are giving us the gold standard. If you're putting in quotes, it seems like your saying, "Well, this looks pretty decent, why don't you see if it works for you?"

Down that road leads absurdities like Campy/JIS spindle compatibility tables.

EDIT: Well, it looks like I'm being a skeptic for no purpose, since Pars' file share says it was a Campagnolo publication. Sorry, Lynn!

ISTR that Record News was Campy's newsletter sent to their dealers and distributors.

I keep thinking that what I learned decades ago is that rear end width (no, not the part that's relevant to saddle selection!) is not a factor in chainline for a road bike. The chainline measurement is a distance from the center plane of the frame to the right. At that distance you should find the midpoint of the group of chainring planes and the midpoint of the rear sprocket cluster planes. When we went to 6-speed we added 6 mm total to the rear spacing, 3 mm on each side. The drive-side flange moved 3 mm closer to the frame center plane relative to 5-speed. The 6 mm-larger width of the cluster is still centered at the chainline distance from the frame center plane. Hence chainline is not changed between a 120 OLD and a 126 OLD, and the BB width for the same crankset is not different between a 120mm and 126mm frame.

What did change is that the bracing angle for the drive-side flange is less than it was with 120, and hence the potential strength of the rear wheel is reduced. But that is not affected by how far the crank sets from the frame center plane.

I don't know why for the early models, Campy had two spindles for 110 and 120, unless they correlated to simply a much narrower tread (Q) for single (pista) drivetrains versus 5x2.

Rear spacing is certainly a variable in frame/drivetrain geometry, but I don't think it is a necessary consideration in setting up Campy spindle BBs, beyond the early 110/120 distinction.

No worries. Official was in quotes because some of that info got superseded by later production. So you have to be careful how you use it.

I guess I would feel better if the Z explanation was in some original source info in Italian.

I'm still mulling over bottom brackets. For my Atala, I need a pre-CPSC Italian bottom bracket. One of my Chicago area bike buddies likely has the part I need, but that doesn't keep me from scouring eBay. I came across this eBay auction a few minutes ago. It seemed odd to me. I think the spindle and cups are mismatched. The cups look to be thin (Record?) cups, while the spindle (70-SS-120) should be for Nuovo Record cups. Perhaps there is a meaning to the "Z" suffix after all? Rather than just link to the image in the ad, I've uploaded it, should it be useful for readers who come along in the distant future.

http://bikeforums.net/attachment.php...hmentid=427722

The Gran Sport and Record spindles (thin cup) would be marked the same as the Nuovo Record spindles (70-SS-120). The only way to tell is measure the distance between the bearing lands. NR for thick cup will be 51mm (51.5mm according to Sutherland's), vs. 56 (or 56.5) for the thin cup.

I'm not sure what significance the color of the spindle has as I've seen silver like this one (and seems to match actual NR spindles) vs. the darker grey which I seemed to associate with the older Record or Gran Sport spindles).

Yes, the black oxide treated spindle came with Gran Sport cranks, while the silver color ones came with Record/Nuovo Record.

That's what I thought, but couldn't find any confirmation.

However, weren't the Record spindles for use with thin cups? The Nuovo Record were the ones for the thick cups.

If so, then that could be the correct set in the ebay auction.