Quoting Tom Dalton <firstname.lastname@example.org>:
> I'm not certain, but I think 120 indicates that these
> spindles will position the crankset to achieve proper
> chainline with a 120mm / 5-speed rear hub.
That would fit with what several other respondents
> It's all a
> little wierd though, because as far as I know Campy
> never simultaneously made different spindles to work
> with 120mm / 5-speed and 126mm / 6-speed rear hubs.
> They made the 68-SS-120 (or 74-SS-120) then they added
> some length when the CPSC changes were made about
I'm assuming you mean Comsumer Products Safety Commission,
but why would these changes be made for safety reasons? Hmmm.
> These were marked 68-SS-120 along with +1.0 /
> +1.5. Later they were just marked 68-SS. By this
> point the standard for rear hubs was 126 and the
> post-CPSC BB's are suited to such use. In any case
> there are definitely pre and post-CPSC spindle
> differences, and one would be lead to believe that
> there are also 120 / 126 spindle differences, though
> none of my observations suggets that this actually
> happened. In other words, if you have a pre-CPSC
> crank use a pre-CPSC BB and it should work with either
> 120 or 126 rear hubs. If you have a post-CPSC crank
> use the newer BB and it too should work with either
> type of hub.
So, would markings of 68 (or 74) == SS (or P) == 120 (or 110)
indicate pre 1977, then the same markings along with the +1.0/+1.5
indicate about 1977, and the 68 == SS indicate post 1977?
> Confused yet?
Not entirely. You'll have to keep trying.
rob hawks, richmond, ca
(sorry about leaving this info off my original post. It was a newbie mistake)