GrizzlyStik....what spine?

[J.B.]

Needing some help here...

I am having trouble determining the spine I need on the GrizzlyStik arrow chart...

I am shooting a 65# DXT with a 28" draw. Arrow length is 27".....any recommendations on what spine & model GrizzlyStiks I should be looking at?

[Outlaw_6]

Broadhead weight? Assuming 100grs, you are probably a .400 spine.

[dagdog]

I shoot a Mathews Chill at 65lbs with 28"draw length, shooting 100gr or 150gr points. I use the GrizzlyStik Momentum 4560's. They have renamed that shaft and are now calling it the 450. I have no problems with the arrow. It flys great and hits HARD. Goes right through just about everything.

[J.B.]

I called and spoke with Grizzly, got signed up for the 650 Challenge they will be sending me a 250 and 330 spine to test out. A lot stiffer than I thought, but that's what they suggested as the head weight is much higher too

[enewman]

Let us know how the challenge goes. I know it sounds stiff. But if your bow is tuned the stiff arrow will fly great.

[enewman]

WHAT IS SPINE?

History

Originally, proper spine was necessary for the arrow shot from a primitive bow to flex as it was shot, so the fletching would clear the bow and not strike the riser. It was discovered that making an arrow strong enough to withstand being shot, yet weak enough to flex while being launched would result in the arrow automatically flexing around the riser of the bow so the tail of the arrow and consequently the fletching would clear the riser and rest. The rest on primitive bows was nothing more than a notch in the riser. This was the birth of what we have come to know as Archer’s paradox. Proper spine is absolutely necessary for proper Archer’s paradox.

Definition

The generally accepted definition of spine refers to the stiffness of an arrow. Although this is generally true, it is far more advantageous to be much more specific when considering the various aspects of spine and what it means to the modern archer.

There are actually two spines; one is certainly the stiffness of an arrow. This spine is a static measurement made by hanging a specified weight from the center of an arrow suspended between two supports, which are a specified distance apart. The resulting value is the distance the arrow deforms from when it was straight. Arrow spine is primarily a function of the materials of which the arrow is made. Because of the intrinsic properties of suitable materials, arrow spine is also directly related to the overall weight of the arrow. The stronger is the arrow spine; the heavier the arrow. This relationship will always be true however, yet-to-be discovered materials will undoubtedly result in stiffer arrows with less weight in the future. There is a limit however, to how light an arrow can be and still maintain a proper Front-Of-Center or F.O.C. balance and its effective hitting power.

The other spine referred to herein is Shot Spine. This can also be referred to as dynamic arrow spine. Dynamic arrow spine is a more descriptive name, but in this article the term shot spine will be used to make a more clear distinction between the two. Shot spine refers to the flexure of the arrow during launch and all the things, which influence the flexing characteristics of the arrow shaft.

Description

Who Should Be Concerned With Spine?
Safety
First of all, EVERYBODY must be very aware of minimum, SAFE arrow spine. NOBODY should ever shoot an arrow, which has a spine too weak for the bow shooting it. All commercially available arrows have a rating of spine that specifies the draw weight range of the bow with which it is to be used. NEVER shoot an arrow that is underrated for the draw weight of the bow being used to launch it. A weaker arrow will be slightly lighter than an arrow with the proper spine, but the slight increase in speed will never be worth the possible injuries to the archer, or innocent bystanders. Also, using wooden arrows of any spine with a high performance compound bow is not a good idea. These are fundamental safety concerns. But what about performance concerns?

Finger Shooters
Who should be most concerned with spine? FINGER SHOOTERS. Proper spine is of value to only those who rely on Archer’s paradox to provide adequate clearance for the fletching on an arrow when it is shot. Archer’s paradox relies on the flexure of the arrow to perform its task properly. Also, only finger shooters deliberately induce a sinusoidal travel path to the string upon release. The curved path of the string always starts out traveling toward the centerline of the archer regardless of whether the archer is a right or left-handed shooter. This zigzag path will always try to induce an arrow flex. Because of this fact, archer’s paradox will always more or less work although, many factors affect how well it works.

What are factors, which influence shot spine? The primary and most influential factor is the arrow stiffness. Then comes the remainder, which include: length of the arrow shaft, weight of the arrow tip, and the mass of the arrow nock. The final factor is the acceleration of the string, which is comprised of the mass of the string, the masses of the limb tips, and the draw weight of the bow. Since the draw weight of the bow is considered part of the primary bow setup, it is not considered in spine refinement. The type of arrow rest is assumed to be compatible with this style of shooting.

Just buying arrows of proper spine rating and then blithely chopping them to length and mounting the hottest selling tip on the front, will not result in a properly executed shot that will demonstrate a smooth and proper archer’s paradox. Once the arrow shafts, appropriate to the task at hand, are selected and cut to length, the work of fine-tuning for the best archer’s paradox begins. The tip weight should be selected based on two factors alone. First is the best F.O.C. measurement. Next is overall weight. Of the two, F.O.C. is the more important.

When speaking of shot spine, a weak spine means the arrow shaft will flex more, and a strong or stiff spine will result in the arrow shaft flexing less. To improve the arrow flexing profile one or more of the factors mentioned may be altered alone, or in combinations. This process of fine-tuning shot spine will render a well-executed archer’s paradox and consequently a smooth and accurate shot for the finger shooter. High-speed video is really the only way to clearly and accurately see what an arrow is doing as it is being shot. Using this video technology it is easy to see if more flex is needed or less flex is required to get the flexing of the arrow timed just right so the tail end of the arrow passes cleanly around the rest and riser.

Once it is determined if a change in shot spine is needed then, one or more factors can be used to achieve the desired results. To weaken the shot spine, the tip weight can be increased, unless of course, F.O.C. is at maximum. Alternatively, the mass of the nock might be able to be reduced with the same F.O.C. consideration. Or the mass of the string might be able to be reduced. For instance, if string silencers are hanging on the string, they could be replaced with lighter ones, or removed altogether. Additionally, extra serving around peep sights and nock sets can also be decreased or eliminated. Also the limb tips of the bow may be able to be made lighter. This is especially true of compound bows. The object in this process is to have the tail of the arrow accelerating faster relative to the tip of the arrow, resulting in more flexure, which is by definition, weakening the spine.

To stiffen the spine of the shot, the same factors are employed but in an opposite fashion. The idea of stiffening the shot spine is to lighten the tip, or decrease the acceleration of the string relative to the tip of the arrow. Any change to the weight of the tip or nock must again be considered in relation to the F.O.C. measurement. Be also aware, that adding mass to the string or limb tips will also affect the speed of the arrow leaving the bow.

Release Aid Shooters

Not everyone need concern themselves with the subtleties of properly adjusted spine. Except for consideration of minimum safe spine requirements, there are circumstances, which make shot spine obsolete.

If a bow is designed to give a straight nock travel and built to give adequate clearance between the proper arrow rest position and the riser, so the arrow fletching will not hit anything as it passes by; and the rest is of such a configuration that it will not interfere with a straight arrow path; and a release aid is used to pull and loose the arrow; and the bow has been micro-aligned such as with the Bow, then the stiffer the arrow, the better.

The reasoning is straightforward. Given a straight nock travel to a precisely aligned rest and no interference with the arrow flight from the riser or rest, then the flexing of the arrow does nothing but eat up energy that could be going into arrow speed. An arrow need not flex to fly well. In point of fact, an arrow need not flex at all. All it really needs is to be pushed straight and not bumped after it has begun its trip to the target.

©2008 Scientific Archery L. L. C. Home • Contact Us • About Us • Bow Services • Sales Info • Tech Talk • News • Legal

[Doc Peter]

TY enewman. This is very helpful.

[JW]

WHAT IS SPINE?

History

Originally, proper spine was necessary for the arrow shot from a primitive bow to flex as it was shot, so the fletching would clear the bow and not strike the riser. It was discovered that making an arrow strong enough to withstand being shot, yet weak enough to flex while being launched would result in the arrow automatically flexing around the riser of the bow so the tail of the arrow and consequently the fletching would clear the riser and rest. The rest on primitive bows was nothing more than a notch in the riser. This was the birth of what we have come to know as Archer’s paradox. Proper spine is absolutely necessary for proper Archer’s paradox.

Definition

The generally accepted definition of spine refers to the stiffness of an arrow. Although this is generally true, it is far more advantageous to be much more specific when considering the various aspects of spine and what it means to the modern archer.

There are actually two spines; one is certainly the stiffness of an arrow. This spine is a static measurement made by hanging a specified weight from the center of an arrow suspended between two supports, which are a specified distance apart. The resulting value is the distance the arrow deforms from when it was straight. Arrow spine is primarily a function of the materials of which the arrow is made. Because of the intrinsic properties of suitable materials, arrow spine is also directly related to the overall weight of the arrow. The stronger is the arrow spine; the heavier the arrow. This relationship will always be true however, yet-to-be discovered materials will undoubtedly result in stiffer arrows with less weight in the future. There is a limit however, to how light an arrow can be and still maintain a proper Front-Of-Center or F.O.C. balance and its effective hitting power.

The other spine referred to herein is Shot Spine. This can also be referred to as dynamic arrow spine. Dynamic arrow spine is a more descriptive name, but in this article the term shot spine will be used to make a more clear distinction between the two. Shot spine refers to the flexure of the arrow during launch and all the things, which influence the flexing characteristics of the arrow shaft.

Description

Who Should Be Concerned With Spine?
Safety
First of all, EVERYBODY must be very aware of minimum, SAFE arrow spine. NOBODY should ever shoot an arrow, which has a spine too weak for the bow shooting it. All commercially available arrows have a rating of spine that specifies the draw weight range of the bow with which it is to be used. NEVER shoot an arrow that is underrated for the draw weight of the bow being used to launch it. A weaker arrow will be slightly lighter than an arrow with the proper spine, but the slight increase in speed will never be worth the possible injuries to the archer, or innocent bystanders. Also, using wooden arrows of any spine with a high performance compound bow is not a good idea. These are fundamental safety concerns. But what about performance concerns?

Finger Shooters
Who should be most concerned with spine? FINGER SHOOTERS. Proper spine is of value to only those who rely on Archer’s paradox to provide adequate clearance for the fletching on an arrow when it is shot. Archer’s paradox relies on the flexure of the arrow to perform its task properly. Also, only finger shooters deliberately induce a sinusoidal travel path to the string upon release. The curved path of the string always starts out traveling toward the centerline of the archer regardless of whether the archer is a right or left-handed shooter. This zigzag path will always try to induce an arrow flex. Because of this fact, archer’s paradox will always more or less work although, many factors affect how well it works.

What are factors, which influence shot spine? The primary and most influential factor is the arrow stiffness. Then comes the remainder, which include: length of the arrow shaft, weight of the arrow tip, and the mass of the arrow nock. The final factor is the acceleration of the string, which is comprised of the mass of the string, the masses of the limb tips, and the draw weight of the bow. Since the draw weight of the bow is considered part of the primary bow setup, it is not considered in spine refinement. The type of arrow rest is assumed to be compatible with this style of shooting.

Just buying arrows of proper spine rating and then blithely chopping them to length and mounting the hottest selling tip on the front, will not result in a properly executed shot that will demonstrate a smooth and proper archer’s paradox. Once the arrow shafts, appropriate to the task at hand, are selected and cut to length, the work of fine-tuning for the best archer’s paradox begins. The tip weight should be selected based on two factors alone. First is the best F.O.C. measurement. Next is overall weight. Of the two, F.O.C. is the more important.

When speaking of shot spine, a weak spine means the arrow shaft will flex more, and a strong or stiff spine will result in the arrow shaft flexing less. To improve the arrow flexing profile one or more of the factors mentioned may be altered alone, or in combinations. This process of fine-tuning shot spine will render a well-executed archer’s paradox and consequently a smooth and accurate shot for the finger shooter. High-speed video is really the only way to clearly and accurately see what an arrow is doing as it is being shot. Using this video technology it is easy to see if more flex is needed or less flex is required to get the flexing of the arrow timed just right so the tail end of the arrow passes cleanly around the rest and riser.

Once it is determined if a change in shot spine is needed then, one or more factors can be used to achieve the desired results. To weaken the shot spine, the tip weight can be increased, unless of course, F.O.C. is at maximum. Alternatively, the mass of the nock might be able to be reduced with the same F.O.C. consideration. Or the mass of the string might be able to be reduced. For instance, if string silencers are hanging on the string, they could be replaced with lighter ones, or removed altogether. Additionally, extra serving around peep sights and nock sets can also be decreased or eliminated. Also the limb tips of the bow may be able to be made lighter. This is especially true of compound bows. The object in this process is to have the tail of the arrow accelerating faster relative to the tip of the arrow, resulting in more flexure, which is by definition, weakening the spine.

To stiffen the spine of the shot, the same factors are employed but in an opposite fashion. The idea of stiffening the shot spine is to lighten the tip, or decrease the acceleration of the string relative to the tip of the arrow. Any change to the weight of the tip or nock must again be considered in relation to the F.O.C. measurement. Be also aware, that adding mass to the string or limb tips will also affect the speed of the arrow leaving the bow.

Release Aid Shooters

Not everyone need concern themselves with the subtleties of properly adjusted spine. Except for consideration of minimum safe spine requirements, there are circumstances, which make shot spine obsolete.

If a bow is designed to give a straight nock travel and built to give adequate clearance between the proper arrow rest position and the riser, so the arrow fletching will not hit anything as it passes by; and the rest is of such a configuration that it will not interfere with a straight arrow path; and a release aid is used to pull and loose the arrow; and the bow has been micro-aligned such as with the Bow, then the stiffer the arrow, the better.

The reasoning is straightforward. Given a straight nock travel to a precisely aligned rest and no interference with the arrow flight from the riser or rest, then the flexing of the arrow does nothing but eat up energy that could be going into arrow speed. An arrow need not flex to fly well. In point of fact, an arrow need not flex at all. All it really needs is to be pushed straight and not bumped after it has begun its trip to the target.

©2008 Scientific Archery L. L. C. Home • Contact Us • About Us • Bow Services • Sales Info • Tech Talk • News • Legal

Condense all that mess!!!!

[J.B.]

Condense all that mess!!!!

I didn't read any of that, but I went ahead and bought the 250 spine Grizzly Stik's!!!!!!!!!! 650gr with broadhead. Ready to hunt.

The 650 grain arrow hit the x-ring the same as my 400gr Bemans out to 30 yards

[enewman]

Condense all that mess!!!!

i didnt write it i took from someone smarter then me but all you have to do is read the last part

the bad thing is i took my time to get the info and the op didnt even read it

[JW]

i didnt write it i took from someone smarter then me but all you have to do is read the last part



the bad thing is i took my time to get the info and the op didnt even read it

Ha! You cheated.

[Problem Child]

i shoot the 250s cut to 29" with a 175 grsin Silverflame. they shoot great


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