IBO speeds

keyway05 · 02-22-2006, 11:22 AM

I'm looking for a new bow for the upcoming season. I see alot of companys' are publishing their bows specs and IBO speeds. Can someone tell me what the formula is for figuring a bows IBO speed? The standard is 30" draw at 70lbs, but I only have a 29" draw and pull about 65lbs. I need a formula to figure the difference. Thanks! [8D]

newman1 · 02-22-2006, 03:35 PM

10 fps.for every inch loss in draw length
2 fps.loss for every pound draw weight.

You are not gonna get anywhere near what the listed IBO speeds are with a fully loaded string.What kind of bow are you looking at getting?Good luck

The Rev · 02-22-2006, 05:32 PM

The best way to know your speed is get it chroned at a bow shop... else your just guessing, IBO speed doesn't mean squat. My IBO speed is between 342- 345 and I am shooting about 305 FPS with my target arrows, 290 with my hunting arrows...

keyway05 · 02-22-2006, 05:32 PM

I'm currently looking at an 06 Bowtech Tomcat.

The Rev · 02-22-2006, 06:46 PM

Quote:

ORIGINAL: keyway05

I'm currently looking at an 06 Bowtech Tomcat.

Tomcat IBO speed is 315 FPS.

djkiller · 02-22-2006, 08:06 PM

I wouldnt rely on the manufacturers IBO specs. most are so inflated you'd laugh. I'd be more concerned w/ brace height before Id worry to much about how fast it is. With most bows out you'll be close to the 280-300 fps any ways.

Primitive Weapon · 02-23-2006, 02:06 PM

from what I've read, the IBO speeds are determined using the bow with nothing on the string (no silencers, peep sights, brass nocks,etc ) to elimate things to slow the string down. They also us ultra light arrows, around 5gr/inch.

Again, that's what I have read.

parker1 · 02-23-2006, 05:11 PM

It depends on what weight of arrow you are shooting. Your IBO rating on the tomcat is 315 so minus 10 fps for your 29" draw. You said you are going to shoot 65lbs so that means if you shoot a 5 grains per pound arrow you can shoot a 325 grain arrow. Now you would be at around 305 FPS but you also have to minus for your loop or nock, peep sight, string silencers etc, that you place on your string.That would probably put you at around 296 fps. But of course your hunting arrow will probably be heavier then 5 grains per pound so that would change your speed once again.