IBO speeds mean nothing

[Prebanpaul]

Just to let you knew bow hunter know this     when you see that a bow says it has an IBO speed of lets say 315fps    that does not mean anything.  They rate them off of a machine rest with a minimum of a 30 inch draw and a really really light arrow.  My new martin said the IBO was 315.  I have a 28.5 inch draw and shoot pretty much standard weight arrow.  My actual speed on a crono graph was 242fps.  Big Big diffrence.  Wish someone would have told me this.

[mg66]

IBO and AMO ratings are pretty much used to rate one bow to another. And you are right they pretty well mean nothing in the real world.

Energy is the key imho ... shooting a 490 grain aluminum arrow / 30" draw / 65lb draw weight @ 247fps OR a 375 grain carbon arrow / 30" draw / 70lb draw @ 283fps both calculate to approximately 66-67 ft/lbs. My bow has an advertised IBO rating of 320+ fps so nowhere near the rated speed.

Also I might add, string spiders, nock points, kisser button, peep sight, etc all rob fps off your arrow speed.

I have tried to explain the ratings on my web site with speed facts using a chrono on my Mathews Ultra2 at http://www.bghi.us/index.php?x=bowspeed

[Travis Shuck]

The IBO speed rating does mean something.  You probably won't get that speed out of it.  IBO standards are 5 grains per pound of draw weight, 30 inch draw, 70# draw weight.  Since it is a standard way to measure bow performance it is a good means by which to determine the faster bow. The faster the bow the more kinetic energy it will produce.  Unless you shoot a 350 grain arrow at 70# with a 30 " draw, you will not get the IBO speed out of it.  However if you were to choose a bow that had a lower speed rating, you would be shooting those same arrows slower than you are now.

[ronbow]

The IBO speed rating does mean something.  You probably won't get that speed out of it.  IBO standards are 5 grains per pound of draw weight, 30 inch draw, 70# draw weight.  Since it is a standard way to measure bow performance it is a good means by which to determine the faster bow. The faster the bow the more kinetic energy it will produce.  Unless you shoot a 350 grain arrow at 70# with a 30 " draw, you will not get the IBO speed out of it.  However if you were to choose a bow that had a lower speed rating, you would be shooting those same arrows slower than you are now.

Exactly. I consider IBO to be the equivalent of horsepower rating when I buy a truck. It's a comparison factor when deciding which product to purchase but only one of many factors. I go for at least 305 IBO and 300 hp