I have an 80's Ross road bike. My left crank became loose so I ordered a replacement off of the net. From my research, I ordered a JIS style square taper. Problem is, the new crank I received has a narrower opening than the width of the taper on the shaft. Based on what I have read, a JIS should be very similar with an ISO taper. The difference between the new JIS I ordered compared to what is on my bike has got to be slightly more than a 1/16". The JIS crank doesn't even start over the taper of the shaft. What am I missing? Thanks in advance.