Originally Posted by
Kontact
A couple of things:
No one but the shop guys noticed what was loose or why. There is an assumption that it was the BB, but it sounded like the crankarm to me.
Yes, it could have been any number of things. We were all guessing. But the original so-called mechanic's diagnosis was wrong.
In any case, I think we're all glad it was the easiest to fix.
Originally Posted by
Kontact
A 113mm DA spindle could be pre or post 1985, and the one in the picture looks like the post '85 Japanese taper 7400 version.
Agree. The earlier type had the old loopy S Shimano logo, IIRC.
Originally Posted by
Kontact
The other thing is that it is said that all the different kinds of tapers are 2° in the various 3rd party manuals, but this doesn't appear to be true. Has anyone else ever actually compared the tapers by holding different spindle tapers against each other to see if the spindles remain parallel?
I have, and Mavic or Campy spindles do not remain parallel to Shimano spindles when you do this. One of them is either more or less than 2°.
There is an oddball 3° taper crank, the SR (Sakae) Silver, but those are rare; I myself have only seen one or two. Everyone else uses the nominal 2° taper. But yes, there is likely to be some difference due to different manufacturing processes and tolerances. Some cheap spindles have the taper formed in the forging, higher-end ones are machined more precisely.
Here's what Sutherland's says about the matter: "Except for 3-degree axles, differences in the taper angle of individual axles due to manufacturing tolerances are greater than the average differences between brands."
This is not to sound dismissive; they're not my words, I'm only the messenger. I would add that crank taper holes are subject to the same looseness of tolerance. In any case, within a range of tolerance, the crank taper holes will form to the spindle anyway. So long as everything is installed properly, these tolerance differences should not cause problems.
FWIW, both ISO and JIS spec the 2° taper. The ISO includes a tolerance limit (±5 minutes of angle per side, or 1/12 of a degree.)
Originally Posted by
Kontact
If the DA spindle works, then it works. But that isn't the information we had when the thread started, and if the BB or crank arms develop play again I would seriously consider looking more closely at that Japanese spindle.
Perhaps. The Campagnolo 115.5 would have been the better one to start with. At this point, however, the taper hole is formed to the Shimano. So as long as the bolt isn't bottomed on the spindle end, the crankarm isn't bottomed on the taper shoulder or cup, and nothing is hitting anything on the frame, I'd say to stick with it.