AREID

Hi,

I am wondering if anyone can answer a question for me. I have a late 70s/early 80's suntour superbe crankset for road (double). My question is about the taper. I am familiar with Sheldon Brown's site, which has been very useful, but I'm still not quite sure.
I've tried the crank on a Shimano UN72 BB (which I'm assuming is JIS) and it didn't go on all the way (which is consistent with the crank being ISO). However the Sugino cup and cone BB spindle (which came with the bike and fits the crank well) tapers to the exact same size end as the UN72 and is shorter than the (JIS) UN72, which sounds contrary to what I've read about ISO vs. JIS.
Though they look the same to the naked eye, obviously the crank only goes 2/3 of the way onto a JIS spindle, so I'm assuming its ISO.
I've read also about odd suntour tapers.
But I'd like to be more sure before I order a new BB. Can anyone shed some light on this?
Thanks in advance.