Right, 1-7/16" spanner size equates to 36mm spanner size, although inch and a half is a smidgen more.

A 36mm spanner sized nut should equate to an M24 thread size, or roughly an inch in old money.

An M30 thread should use a 46mm spanner size.

Some good back pocket info HERE which I think is pretty accurate in effort.

Is this any use? Who knows, my car's a long way from me too as I write..

Steve