# Arrow Spine for recurve vs longbow



## ripforce (Feb 15, 2010)

I have 2 Bama longbows [email protected] and I draw 291/2, shoot Beman MFX 500 spine cut to 30.5 with 125 gram heads fly great out of both bows you should be okay! I also shoot Carbon Express Heritage 150s with 125 heads, they fly great out of both longbows!


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## Viper1 (Aug 21, 2003)

Kevin -

The two factors are the degree of center shot (most important) and the rate of limb acceleration ie: speed.. The closer to center and the faster the acceleration, the stiffer the spine requirement.

Most longbows aren't as close to center shot as a lot of recurves, some of which are actually cut past center and SOME recurves are faster than SOME longbows. (These days the difference in speed between LB and recurves isn't as great as it once was, due to some LB designs.)

Viper1 out.


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## KevinV (May 14, 2008)

Ah I knew it must've been something to do with acceleration. Also the long bow's I'm looking at all seem to have recurve type risers so I guess I might not have to change those arrows. I've been looking at custom longbows and I really liked the look of the Bama bows. How do they shoot? Pretty fast?


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## Viper1 (Aug 21, 2003)

Kevin -

No idea on the Bama bows. Just remember, unless there's a huge disparity in speed, the degree of center shot is the biggest factor.

Viper1 out.


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## Tzi-Oxphon (Nov 27, 2008)

http://www.google.com/url?sa=t&sour...4dSoBg&usg=AFQjCNEpBVdjo2LjILiPi0x0ZKM_y7kwTQ

Measure the amount of centershot. This calculator has a measurement standard from centershot outward distances.


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## dayrlm (May 20, 2010)

typically every arrow as it leaves the bow starts out moving away from the bow and then curves back toward the center. The weaker the spine the more it curves back. The stiffer the less. On the early longbows there was no shelf and so it needed to come back more than a recurve with a shelf cut into it. That is why the recomendation is that for the same poundage and drtaw length a longbow needed a weaker spine than a recurve. I admit I am not certain how speed of the arrow affects this curve.

Hope this helps.


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## KevinV (May 14, 2008)

Hey that calculator looks pretty helpful do you use it with any success for your own arrows? And I guess I'm just going to have to measure the "center-cutness" if that's a word of the bow to get good shooting arrows.


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## Tzi-Oxphon (Nov 27, 2008)

I use it often with a good "ball park" figure which is very close to the correct deflection of what I need. The inputs must be fed into it with as much accuracy as possible. Fine tuning will require further shooter refinements to the arrows length.
The amount an arrow bends is directly related to how much it is offset from a linear path from the Bowstrings dynamic force imparted to the rear of the arrow. In other words, the closer to center shot, more spine and less deflection. This sounds great until tuning becomes a futile effort trying to shoot from a center shot Bow, with the arrow set at center shot. The rub comes in because of the Paradox initiated upon the arrow by the finger release. If an Archer has a consistent, almost perfect release, he may get tuned with this arrangement, somewhat.
The real beast is actually in how the arrow starts it's rotation. Clockwise for RH shooters, preferable. This little bit of outward adjustment from center shot helps start the rotation in the correct direction, and also gives the Archer a little forgiveness in his release. Seems a little complicated. The pressure Button can input many variables and tuning adjustments but, that is another subject.


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