# Aluminum to Carbon arrow size conversion?



## rock monkey

no...they're listing them in spine ratings. arrow sizes are a whole different animule.

outer diameter is just that....the diameter of the shaft in nearest 64ths of an inch. on aluminum arrows, it's the first 2 numbers of the 4 digit sizing code. second set is wall thickness in thousandths. 2216 breaks down as 22/64 OD, and .016" thick walls.

carbon arrows are spine rated...deflection of the shaft supported at 2 points, 28 inches apart with a 2lb weight. measurement of sag, to make it simple. 400 spine means .400 inches of sag. 340 spine, .340 inches of sag.

since the 'modern' archers of today only recognize the spine rating method of labeling a shaft, easton has adopted the same system for their aluminum arrows. in a way, they can slim the product line down some and still cover a majority of the bases.

not all arrow companies play the same game. CX's numbering system is counter-intuitive. the smaller the number, the less stiff the shaft and is in no way reflective of the spine rating. easton's system is actual spine ratings. goldtip's method, they use a weight range type system, but their website does list the deflection for each model.

the easton shaft selector on their website will get you into the spine rating range for your setup. take the spine recommendations and look at the other company's websites or product charts.

http://www.eastonarchery.com/products/selection


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