Arrow Speed and Speed Loss
How Do Manufacturers Rate Speed? IBO Speed Ratings are an industry standard of measurement used by all manufacturers. Speed ratings are based on a bow with a draw weight of 70# and a draw length of 30’’ using a five (5) grain per pound arrow (350 grain). Any deviation from these settings will cause a drop in arrow velocity.
Note: The chart below is a general guide for the amount of speed lost when accessories are added to your string.
STRING ACCESSORY SPEED LOSS ITEM SPEED LOSS
Brass Nock 2-4 fps
Peep Sight 3-6 fps
String Silencers 0-6 fps
E-Buttons 2 fps each
Rubber Peep Tube 6-10 fps
String Loop* 1-3 fps * Without brass nocks
VibraBlocks 0-2 fps
Speeds will vary depending on placement and manufacturer of string added accessories.
Speed loss of arrows over IBO standard of five (5) grains per pound (350 grains @ 70# draw weight):
Single Cam Every 3 grains of added arrow weight results in 1 fps speed loss. Example: 30 grains over IBO would result in 10 fps speed loss.
Dual Cam Every 2 grains of added arrow weight results in 1 fps speed loss.Type your paragraph here.