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.)
Do you know where I can read this spec?
Originally Posted by
Ghrumpy
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.
We don't really know if it is bottomed out, or if it doesn't have enough bearing surface as JIS is supposed to go in 4.5mm shallow.
All that said, when I bought my Mavic starfish cranks years ago, everyone swore up and down that it was JIS, so I put it on a recommended Shimano BB. I'm not going to change it now, and whatever spindle length that was suggested put the chainline dead on. But later I did get a chance to compare a Mavic to Campy and they were the same angle, while Mavic to Shimano and Campy to Shimano were not.