Most bow manufacturers’ advertising gives IBO speeds as part of their sales spiel. Most of those specifications cover a range (typically 8 fps) or make claims “up to X fps”. Only one company I come to readily advertises a specific number without a range. Given the IBO specifically states draw length, arrow weight and draw weight, what does this range of numbers represent? Is this standard deviation, extreme deviation or some other range I am unfamiliar with? Thanks again, Konrad
The range is just a tolerance and very few hit the top mark right out of the box.Most hit the low end but with some tuning,some can hit the top number.Not all will and even some of the manufactuers just use it to fudge the ibo and use it as a way to say they are not lieing.Some of them even cheat the draw length to sqeeze a couple more fps out. The marketing is getting out of hand as well as the need for speed.Speed has it's place but it is so misunderstood by the majority of archers and is actually hurting the abilities of some.
IMO IBO speed ratings are complete BS, it is a standard of 30" dl, 70 lb pull with a 350 gr arrow. Realistically an arrow properly spined for a 70lb draw with insert, nock, fletching and field point or broadhead will be well above 350gr. Reduce the draw weight, lop and increase the let off and you can pretty much kiss goodbye any expectation of even coming close the the IBO rated speed.
I think a lot of it has to do with the arrows. I was at my local bow shop the other day and one of the workers was shooting his bow through the chrono and he shoots the destroyer 350 at 70#. I do not know what arrows he was shooting as i did not ask but i did hear a customer go "Holy **** he just hit 364fps" The guy turns around and goes yeah you should try these arrows.
IBO ratings is just another way to rate the bows potential energy and there has to be a mark somewhere.It has been the adopted standard over the AMO standard purely because of the speed numbers are much higher. Arrows can be correctly spined to match the IBO specs but they are not typically correctly spined HUNTING arrows.They are typically target arrows.
