IBO speed ratings, as they "step down"?

Bowhunter57 · Jan 4, 2015

An example of a "speed rating" would be a bow set at 70# with a 30" draw length and a 350gr. arrow weight. A bow manufacturer might show that particular bow at 330 f.p.s.

My question is: How does the "speed rating" change if one or both variables change?

* The draw length is 29" or 28"?
* The draw weight is 65# or 60# or 55#?

Thank you, Bowhunter57

Bigslam51 · Jan 5, 2015

It goes down.

Big_Holla · Jan 5, 2015

It would be nice if they'd break it down a little more, maybe by inch draw lengths and for each peak weight they sell.

Beentown · Jan 5, 2015

The rating doesn't go down as the bow still has the same potential at the rated specs.

A change in specs does change what the real world performance is.

Some bows will actually become more efficient at certain draw weights, lengths and arrow weights.

A Hoyt becomes more efficient with heavy arrows and will exceed it's ratings where a Bowtech likes light arrows.

Milo · Jan 5, 2015

you generally only lose 10 fps by dropping from a 70 to a 60 pound bow. I forget what it is by draw length.. Too many things on my mind at the moment. If it comes to me i will post it.

Milo · Jan 5, 2015

here is an example chart for a hybrid cam system. This is the only manufacturer that i know of that has done this sort of information

Bowhunter57 · Jan 5, 2015

I was asking because I'm considering getting a newer and perhaps faster bow. My Martin Cheetah is rated at 315 f.p.s. @ 70# and 30". However, my bow is a 45-60# model, so it would be topped out at the 60# and then there's my 28" draw length. If I were shooting an I.B.O. rated arrow weight, at my bow's max. draw weight of 60#...I might be getting 290 f.p.s.

Even if I were to purchase a 330 f.p.s. rated bow with my 28" draw length, I wouldn't gain much speed by shooting 60#. I'm not interested in shooting more draw weight than the 60#.

I need to shoot my bow through a chronograph to know exactly what my bow's performance specs are and decide whether to purchase another bow, after I have more facts.

I appreciate all of the information, guys! :smiley_blink:
Thank you, Bowhunter57

Beentown · Jan 6, 2015

Martin's were not known for making published numbers.

I would find a good used (fast) bow on AT. I recommend any of the Hoyt Turbo models, Bowtech Experience and some of the PSE bows (that is if you can stand to shoot any ugly bow).

Vector Turbos can be had for under $500 now on AT.

Strother23 · Jan 6, 2015

I friend that I shoot with some got a new Experience for free due to his older model bow being stolen at a bow shop, so insurance said to pick out everything new (lucky bastard lol). So he pick the Experience and loaded it with top notch stuff and he was shooting his hunting setup at like 312-315fps through the chronograph. At 65lbs @ 29in I believe

Beentown · Jan 6, 2015

Strother23 said:
I friend that I shoot with some got a new Experience for free due to his older model bow being stolen so insurance said to pick out everything new (lucky bastard lol). So he pick the Experience and loaded it with top notch stuff and he was shooting his hunting setup at like 312-315fps through the chronograph. At 65lbs @ 29in I believe

IMHO, the Experience was the best bow on the market last year all things considered.

Bowhunter57 · Jan 30, 2015

Bowhunter57 said:
I need to shoot my bow through a chronograph to know exactly what my bow's performance specs are and decide whether to purchase another bow, after I have more facts.

I shot my bow through a chronograph and 255 f.p.s. was as good as it gets...and then...

* I did some tuning to the cam (it was out of time, due to string stretch), so I twisted the string about 10x.
* One side of the yoke strings had stretched, longer than the other and one side of the split limb was relaxed more than the other. I twisted it about 5x.
* I set the draw weight with a scale, to exactly 60#.
* I cut all my arrows to exactly 27" and switched to 85gr. tips.
* Purchased a new Tru-Ball Scout, wrist release.
* Purchased a new Apex Covert sight.
* Installed a new serving and new d-loop.

I shot my bow through a chronograph again. The reading said, "duplicate", every time I shot 281 f.p.s. :smiley_bril: This bow has always been VERY consistent in its' accuracy, at all yardages. I can't wait to get outside to sight this rig in and see how well it performs.

Bowhunter57

Archertl · Jan 31, 2015

Bowhunter57 said:
I shot my bow through a chronograph and 255 f.p.s. was as good as it gets...and then...

* I did some tuning to the cam (it was out of time, due to string stretch), so I twisted the string about 10x.
* One side of the yoke strings had stretched, longer than the other and one side of the split limb was relaxed more than the other. I twisted it about 5x.
* I set the draw weight with a scale, to exactly 60#.
* I cut all my arrows to exactly 27" and switched to 85gr. tips.
* Purchased a new Tru-Ball Scout, wrist release.
* Purchased a new Apex Covert sight.
* Installed a new serving and new d-loop.

I shot my bow through a chronograph again. The reading said, "duplicate", every time I shot 281 f.p.s. :smiley_bril: This bow has always been VERY consistent in its' accuracy, at all yardages. I can't wait to get outside to sight this rig in and see how well it performs.

Bowhunter57

what is your spine weight? By cutting your arrows and switching to presumably a lighter point you can effect the stiffness of the arrow. plus you upped your poundage. Is that spine arrow still correct to the bow? Just something to consider.

hickslawns · Feb 1, 2015

My Hoyt Spyder is a 60# 29"DL bow. Come grab it and shoot it. Take it to Chuck's place to shoot it. He has a chronograph. That should give you a close idea of drop in numbers from a 70# to a 60#. Not exact, but ballpark anyway.

Bowhunter57 · Feb 5, 2015

Archertl said:
what is your spine weight? By cutting your arrows and switching to presumably a lighter point you can effect the stiffness of the arrow. plus you upped your poundage. Is that spine arrow still correct to the bow? Just something to consider.

When you say "spine weight" are you thinking of how the arrow is rated to the bow's poundage? If so, these arrows are definitely rated to this bow's draw weight and more. They're PSE Radial Weave 200 shafts.

Both cutting the shaft length and dropping the tip weight will increase the spine of the arrow.

Just the same, I'm waiting on warmer weather to shoot this set up at longer yardages, to see how the arrows fly with concerns to accuracy and consistency.

Bowhunter57

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IBO speed ratings, as they "step down"?

Bowhunter57

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Bigslam51

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Big_Holla

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Beentown

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Milo

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