springcaller

I know on aluminum arrows it is diameter and wall thickness. Which you can kinda get an idea of arrow weight and stiffness. How can you tell this same info. about a carbon arrow? Does the numbers on the arrow represent anything or are they just ref. numbers used to look up the arrow specs. Any help is greatly appreciated

mobow

Generally speaking the numbers represent spine deflection....

springcaller

are we talking in milimeters or what? So the smaller the number the stiffer the arrow. The reason I ask this question is because I recently tuned a bow (shooting a carbon) and had to turn the # down in order to get proper arrow flight. I plan on purchasing a new bow70# and I want to make sure I get a stiff enough arrow.

mobow

How long will your arrows be? You will most likely need something in a 340 spine, shooting 70 #'s....BUT, if the arrow is short enough, a 400 will work.

I'm not sure exactly how spine is defined....but it's got to do with how much the arrow flexes...340 is .340" deflection....

springcaller

Thanks, that helps out a lot. I will probably shoot them at 28 or 29". Thanks again for the help.

mobow

You are most welcome. You can visit Easton's website www.eastonarchery.com . They have a spine selection chart there.

springcaller

Thanks again, I came up with either a .365 SS or a .300 ST. I would like to stay around 300 grains total arrow weight so that I can maintain speed. Have you read anything about the ST with theHIT inserts. Does the HIT inserts increase the kenetic energy. I would guess they do just from the little bit Ive read on them.

BGfisher

For 70# you need to maintain at least 350 grain total arrow weight. That includes tip, fletching and nock.

Compared to aluminum carbon arrows are marked pretty goofy. Each manufacturer puts their own numbers on them. Best to check out the web sites of any you plan to look at. Pay attention to their spine charts.

Easton/Beman (same company) mark theirs with the actual deflection. 400 means .400", 300 means .300" and so forth, with the smaller number being stiffer.

Carbon Express is just backwards, 100 being fairly limber and 300 being stiffer. Blackhawk is similar with another zero added to the figure.

Gold Tip Ultralites are like Easton/Beman with the smaller number being stiffer. Then they have XT's that are marked with the approximate poundage they re to be used at, like 5575 (55 to 75 pounds), 7595 being stiffer. Depending on the length this can be misleading, too. Most guys shooting 70# or so are better off shooting the XT 7595.

Almost without exception carbon arrows shoot best if on the stiff side, meaning they are very adaptable and more tolerable of shooting errors if stiffer.

It does get a bit confusing does it not?

BGfisher

Forgot to finish. The HIT inserts do not add to kinetic energy. KE is a number (only a number) produced by a combination of speed and arrow weight. The insert is just a component of that arrow weight. Being a little heavier than standard inserts (depending on the arrow you shoose) it can add a little to FOC, which can be desireable, but FOC can be manipulated with different weight points and fletching style and size.

springcaller

Thank you very much, Ive been trying to figure it out with no real luck. I went to the bow shop today (hopeing they had the gaurdians) and asked them the same question. When I read about them on the easton siteI thought that it might add energy but I hear now (from the bow shop) that it is a balance thing. Thanks again