Originally Posted by John10568

The knurled nut only works with a high end true track crankarm spider, which has counterbored recesses for the shoulders to fit into, such as a Sugino 75. Lower end cranks, such as the Sugino RD2 are road crank conversions, and lack these recesses, since these are provided by the missing inner chainring. Another problem that sometimes occurs when changing from 1/8 to 3/32 chainrings is that the nut is too long, and the bolt bottoms out on the nut instead of the chainring, such that the chainring is never properly tightened.