Offset grinding crank ?

[Mark Yacavone]

Originally Posted by Dave Gantz

Anyone know the origin or purpose of the .013 rule? (Is it actually .015, .002 to be safe?)
As John implied, the small amount of cubic inches (inch?) gained seems, even though every little bit counts, hardly worth it, unless there's an ulterior motive.

Dave, Years ago , some crank strokes turned up short in teardown. NHRA decided there might be an advantage in altering the b/s ratio. They decided the limit would be + or - .015.
Of course come crank companies began to offer "rules rider " cranks at + .013..So it began..
Not a lot there, but you might as well take it. Plus, a smaller crank pin can't hurt, can it?