ORIGINAL: hunter9022
Ibo speed is when they take an arrow 30 inches long, weighing 5 grains per inch, and shoot it out of a 30 inch bow pulling 70 pounds.
This is incorrect. The common IBO spec is a 70 pound bow, 30" draw length (generally, some manufacturers cheat since there actually is no such thing as an official IBO spec unlike the AMO/ATA spec), and an arrow weighing 5 grains per pound of draw weight..i.e. 350 grains.