Originally Posted by
Road Fan
For the first comment: I don't see a clear story that 115.5 is the correct length.
[MENTION=20548]JohnDThompson[/MENTION] settled that (thank you sir,) since apparently you didn't believe me.
Originally Posted by
Road Fan
And if it is, my main point is that a few mm difference might not be significant for the OP once it's all installed and torqued.
Agreed. One of my points, in fact.
Originally Posted by
Road Fan
One thing we don't know is how good the Campy cup/Dura spindle installation was: Q, Chainline, symmetry, chain stay clearance, clean chain running. This is where I would do trial assemblies, to make sure (if it was me) that my new installation is not worse than my original installation.
Granted, it's a good idea. Then again, as you just said, a few mm difference might not be significant.
In any case, this is the original installation as the OP received the bike. OP reported it was working fine until the DS cup unscrewed. Bike shop failed to diagnose the problem correctly, and prescribed a "fix" that was not only erroneous but also irrelevant, and flawed in its reasoning. I'm sure they are doing their best, but it was simply not what the OP needed. And then we had to put the whole irrelevant JIS/ISO distraction to bed a couple times.
I have never told the OP not to do any test fitting or measuring. Once he figured out what had happened, I told him not to buy what the bike shop was selling so he wouldn't have to mess with redoing what was working fine, epicyclic forces excepted. Then I set out to see whether or not, as best as anyone can tell without laying hands on it IRL, that his setup is acceptable. Please see below for further calculations.
Originally Posted by
Road Fan
Honestly, I don't think we even have clear evidence that the chainset is Super Record or something older. And if the cups were for Super Record, the cup is made for 3/16" balls, and hence ¼" balls are not going to fit the races right, and the lateral relationship between even a correct spindle and the cups (hence the frame) will not be right.
OP posted photographs that show clearly it is a date-stamped 1984 Super Record crankset, Nuovo Record cups with 1/4" balls, and a Dura-Ace spindle. I've already shown that the later Dura-Ace taper is the same as the Campagnolo, according to Sutherland's.
If you have a Sutherland's, you can use their tables to estimate how good a fit a particular mixed set of cups and spindle might be. (Note that their "factors" are their own calculations and represent mm, but are not simply dimensional measurements.)
According to their chart, The correct Campagnolo 70-SS spindle has a center width factor of 72 and an axle end factor of 9.
The Dura-Ace 70 W 113 has a center width factor of 71 and an end factor of 11.
Total factor difference is +1 to Dura-Ace. Generally speaking, close enough to work. More than likely, the crankarm will be 1 or 2mm more outboard DS than the Campagnolo 115.5mm. Left side might be a couple mm closer to the frame. Judge for yourself if this is going to be a problem but in my experience, classic steel frames have more than enough clearance for that.
The lock ring will engage about one less thread. And that's probably fine, BB shells are IME more often under width than over width because of facing.
Like you said, a couple mm difference might not be significant.
Not that it matters, but it is my belief that BITD someone did these same calculations and put the BB together as the OP found it. These reference materials were fairly common in bike shops before the internet.