Proper Spine

[woody]

I was looking at an arrow chart in 3Rivers only to discover that my arrows are apparently horrribly underspined.  According to their formula I should be using arrows of about an 70 lb. spine for my 50 lb. longbows.  I always knew there were allownaces for length, tip weight, center shot, etc., but I had no idea I should be 20 lbs. over my draw weight.  Does that sound correct? What do you all shoot?

And yes, I am not a good shot with my current arrows, so maybe I need to experiment a bit.

[NTD]

Need to know arrow material, length, and point weight.  I shoot a 55lb bow with 125 gr. points and a 30 inch tonkin arrow.  So I shoot a 65 to 70 lb spine.  Mechslasher recently posted his spine calculator, Its good stuff.

[woody]

I got my info from TTB, but I came up with completely different conclusions.

[Justin Snyder]

Generally speaking you should be 10-15# under the bows draw weight. The only way you would want 20#over is if you are center shot, shooting 32" arrows with very heavy points.

What weight bow are you shooting, is it center shot, what length of arrow and what weight of point?

[stringstretcher]

To get a starting point with any arrow material, if you take the number 26 for amo deflection and devide it by your bow weight, in you case 50 you will come up with a deflection of .520.   That formula has worked for any bow that I have ever set up and works just fine.  Or if you have a deflection number that is amo, you can take that number , .520 and devide it by 26 and you will come up with a poundage of 50.  This is using 125 grain points and you will have to play with length, but this formula is also for a 28 inch arrow.  If you go longer, add 5 lbs spine per inch, if under subtract 5 lbs per inch.

[scattershot]

Most of those charts are set up for compound shooters, even though they say they are for recurves and longbows. Good starting point above, 10# or so below bow weight, and go from there.

[ricktrojanowski]

A big variable is the design of the bow.  A self bow that without a cutout for an arrow pass is going to require an arrow of less spine than a centershot bow of the same weight.  Like others have said the best plan is to experiment with various spines and point weights to see what shoots best.

[HatchA]

Not forgetting the difference between American spine and European spine calculators/testers.  I've just spent the evening learning a valuable lesson in that...  U.S. 50-55# spine equates to 55-60# European spine 

Just means I'll keep the shafts long and finish my bow to 60#

[Del the cat]

That sounds back to front to me.
A longbow (assuming you mean English Longbow (as there isn't really anyother sort ) Needs a lower spine generally as the arrow has to flex more around that big fat handle...there is no cut away or narrowing.
My 75pound longbow shoots 50 spine arrows fine and my little 40pound shoots 'em too as it has a pretty narrow grip.
(Mind this all has something to do with me being a lazy git who doesn't like making loads of different arrows! Generally the longbow shoots 11/32 shafts with heavier points, but it will shoot the light 5/16 with no prob.)
Del

[Mechslasher]

list everything about your rig, that'll give us more to go on.  alot of bows will shoot alot of different spined arrows but to get the best accuracy/consistency, you will need to fine tune your setup.

[George Tsoukalas]

Why do you need a spine chart to see if your arrows are flying straight? You should see nothing but fletch. See Selfbow Care and Tuning on my site. Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/