IBO speeds a crock?

[johnf]

Why do they list IBO speeds for bows that can't pull 70lbs? If the IBO is with a 70lb bow with a 29" draw isn't the bows performance at that weight and length pointless if the bow tops out at 50lbs and 28" draw. Why don't companies just list the best performance they can get out a bow at it's maximum settings?

[hutchies]

Because you have to have a standard to compare them all by. All bows are tested at IBO standards which is 70 lbs, 30 inch draw, with a 350 grain arrow. If you know the IBO speed you can calculate about where you are. IBO speeds are a crock though because some won't make it to their rated speed. It's best to find a chrono and find out how fast your bow actually is.

[okiedog]

Because you have to have a standard to compare them all by. All bows are tested at IBO standards which is 70 lbs, 30 inch draw, with a 350 grain arrow.

Spot on. You have to have a consistant method to compare them all, and that is what the IBO is for. Do you know how many different weights of arrows I can shot through one of my bow to change my FPS? Alot!

[redkneck]

It is a crock, but better than nothing. To the manufacturer it's a performance measurement that sells bows - period.

[johnf]

I guess it's just me, but I'd rather know what my bow can do in the real world, not in theory.

[hutchies]

That's why God gave us speed calculators

[johnf]

I'm thinking when my new limbs come in I'll just put some arrows through the machine at the shop and see what it does.

[buckee]

:)

[redkneck]

:)

Couldnt have said it better myself Steve, you da man!

[fly]

I don't take offense to the IBO. The problem is with the manufacturers. Some will publish speeds that are exagerated. I hear Hoyt will actually underestimate! Can't figure that one out?

http://www.bowhuntingmag.com/field_tested/BW_hoyt_0209/

[Straight Shooter]

Speed Sells.

[The_Kat]

Speed Sells.

And it's WAY overrated. If ya wanna shoot the fastest thing you can get your hands on, shot a gun. 300 is more than fast enough.

[Tom2008]

The IBO is there to show people what that bow can do for a rating. If there wasn't any IBO than the bow would have a missing selling point. Some people can get the IBO rating and some can't. If your bow has a high IBO rating, lets say 340, and another one has 310. If you are a 27 inch draw at 70 lbs you will get the higher speed with a 340 IBO bow than you will with a 310. You wouldn't know that if there was not IBO rating.

[johnf]

The IBO is there to show people what that bow can do for a rating. If there wasn't any IBO than the bow would have a missing selling point. Some people can get the IBO rating and some can't. If your bow has a high IBO rating, lets say 340, and another one has 310. If you are a 27 inch draw at 70 lbs you will get the higher speed with a 340 IBO bow than you will with a 310. You wouldn't know that if there was not IBO rating.

You would if they would just post the results they get with the bow maxed out. How much trouble would it be to set a bow up and shoot it at each draw length and weight with properly spined arrows and get a 10 shot average with each set-up? Not that hard then they could say the actual speed in the real world. I'd much rather know that my bow will shoot 237-244fps at 27" and 43lbs than to know at 70lbs and 30" it will shoot at 298fps. Heck at 70lbs in the real world the limbs would probably break.

[The_Kat]

Heck at 70lbs in the real world the limbs would probably break.

I understand your frustration with IBO ratings. Something that amuses me is that the Monster is having ALOT of trouble producing the speed it claims.

But Tom and Bryan nailed it on the head with their information on what the IBO is and why it is the way it is.

As for limbs breaking at 70lbs.....not even close. I shoot 70 lbs and there are bows that shoot 80lbs.

[Tom2008]

You would if they would just post the results they get with the bow maxed out. How much trouble would it be to set a bow up and shoot it at each draw length and weight with properly spined arrows and get a 10 shot average with each set-up? Not that hard then they could say the actual speed in the real world. I'd much rather know that my bow will shoot 237-244fps at 27" and 43lbs than to know at 70lbs and 30" it will shoot at 298fps. Heck at 70lbs in the real world the limbs would probably break.

That is where the selling point comes back into play. They don't want you to know or they would rather have you figure it out for yourself after you buy it. If you buy it knowing that it can possibly hit that speed with certain specs. then they know you'll think about buying it if that is what you want.

[Tom2008]

I understand your frustration with IBO ratings. Something that amuses me is that the Monster is having ALOT of trouble producing the speed it claims.

But Tom and Bryan nailed it on the head with their information on what the IBO is and why it is the way it is.

As for limbs breaking at 70lbs.....not even close. I shoot 70 lbs and there are bows that shoot 80lbs.

There are even bows that shoot up to 100lbs and limbs still don't break. Limbs are tested for each poundage and they are built differently depending on what poundage someone wants.

[okiedog]

As for limbs breaking at 70lbs.....not even close. I shoot 70 lbs and there are bows that shoot 80lbs.

Yep.. the limbs will be fine. I use to pre-load my bows and get them to 74-75 lbs. That was before I started having shoulder trouble.:bummed:

[ShortDraw]

Another way to look at it.. IBO is measured with different arrow weights at different poundage's.

70 lbs is measured with a 350gr. arrow

60lbs. with a 300gr. Arrow

and so on.

On top of that, you have roughly 10fps lost per every inch you drop off of 30" DL.

So, for example. Take a bow that shoots 320fps IBO. your draw length is 28" and you want to shoot a 350gr. arrow at 70lbs... your looking at around 300fps. before string speed deducts.

If you wanted to factor in heavier arrows past that your looking at about a 4fps speed loss for every 20gr. of arrow weight.

Hope that helps

Short

[johnf]

I understand your frustration with IBO ratings. Something that amuses me is that the Monster is having ALOT of trouble producing the speed it claims.

But Tom and Bryan nailed it on the head with their information on what the IBO is and why it is the way it is.

As for limbs breaking at 70lbs.....not even close. I shoot 70 lbs and there are bows that shoot 80lbs.

But if my bow is 30-40lbs and maxes out at 43 I wouldn't think it would be safe if even possible to crank it up to 70.

[okiedog]

But if my bow is 30-40lbs and maxes out at 43 I wouldn't think it would be safe if even possible to crank it up to 70.

You are right on that point.. I miss understood you when you said it wouldn't be safe to shoot 70lbs. It can be adjusted to pull more than 43lbs but I wouldn't be putting that much stress on those limbs:)

[m gardner]

It's all sales hype, but very useful information. I won't buy a fast bow because I know it's just like a high performance car. It'll need more maintenance. Some are also hard to draw and shoot. My two bows I shoot now are easy to shoot and maintain. The Mathews Classic hardly ever needs tuning or string replacement and the Martin with the old M-Pro Cam is as sweet to draw and shoot as they come. They are fast enough and accurate.

mark

[Tom2008]

You are right on that point.. I miss understood you when you said it wouldn't be safe to shoot 70lbs. It can be adjusted to pull more than 43lbs but I wouldn't be putting that much stress on those limbs:)

You would have to buy a new set of limbs for it that would allow 70 lbs on that bow.

[hutchies]

I understand your frustration with IBO ratings. Something that amuses me is that the Monster is having ALOT of trouble producing the speed it claims.

Hmmmmmm......... first I've heard of that. What alot of guys don't realize is that you don't just pull a bow out of the box and it hits IBO speed most of the time no matter what bow you are shooting. Time the cams, check the specks, check the draw weight, and then chrono it. If it isn't hitting where it should there are still things you can do to gain some speed. Preloading the limbs, speednocks, looser nocks, new strings will a few less strands. If it is too fast more than likely I'm not going to turn the bow down but instead add weight to the arrow. Heavier arrows plane less........The key here is that the IBO number you see is a standard because I know where and how I can manipulate it from there. :robot:

[johnf]

Hmmmmmm......... first I've heard of that. What a lot of guys don't realize is that you don't just pull a bow out of the box and it hits IBO speed most of the time no matter what bow you are shooting. Time the cams, check the specks, check the draw weight, and then chrono it. If it isn't hitting where it should there are still things you can do to gain some speed. Preloading the limbs, speednocks, looser nocks, new strings will a few less strands. If it is too fast more than likely I'm not going to turn the bow down but instead add weight to the arrow. Heavier arrows plane less........The key here is that the IBO number you see is a standard because I know where and how I can manipulate it from there. :robot:

But if you have to do all that stuff to it to reach the IBO speed then doesn't that prove that the speed isn't accurate. This takes me back to that escort analogy. The speed they give you should be the speed out of the box with what's on the bow. I can take a sock corvette and with enough money make it as fast as a zr1, but Chevy shouldn't tell me it can go 200+mph unless that's really how fast it can go.