|Arrows have different sizes, called spines. The spine doesn't refer to the arrow's length or diameter - but rather to its strength (or stiffness).
Unfortunately, the rating system is a little confusing. Manufacturer spine sizing systems may be arbitrary (100, 200, 300, 400) and may or may not reflect actual spine deflections (stiffness). This system is different from one arrow manufacturer to another. And some manufacturers list spine sizes in ascending order of stiffness - others in descending order.
Do not assume a 400 arrow in one brand is equal to a 400 arrow in another brand. For example, a "Carbon Express Maxima 250" has an actual spine deflection of .404", not .250", as the published sizing seems to suggest. So a Carbon Express 250 arrow has roughly the same spine deflection (stiffness) as an Easton 400 (which is sized according to actual deflection measurements). So this can get a little tricky. To be safe, DO NOT assume an arrow's spine size is the arrow's actual deflection, and DO NOT assume that what you know about one brand of arrow translates to another brand with regard to spine sizes.
You must also remember that actual spine deflections are counter-intuitive. Higher deflection numbers actually denote weaker shafts. A deflection is a measurement of how much the shaft bends. The less the shaft bends, the stiffer it is. So a deflection of .300" is actually much stiffer than a deflection of .500". Don't assume that MORE is MORE. A .500" shaft would be a terrible - even dangerous - choice for a men's hunting bow.
See actual arrow specification data before selecting an appropriate spine stiffness for your bow. If you need help, call our pro-shop at 877-410-7811 or email us for assistance. Still confused? Get the full lesson from the top!