Modern Compound (Hard Cam)
Compound (Medium/Soft Cam)
Recurve / Traditional
Recommended Victory Spine:
Understanding Victory Arrow Spine
Choosing the correct arrow spine is the most critical step in tuning your archery setup. "Spine" refers to the stiffness of the arrow shaft. In the Victory Archery lineup, getting this right ensures that your arrow flexes just enough to clear the riser but recovers quickly for a flat, accurate flight path.
How the Calculation Works
The Victory Spine Calculator uses four primary metrics to determine dynamic stiffness requirements:
Draw Weight: As poundage increases, the force exerted on the shaft increases, requiring a stiffer (lower numerical) spine.
Arrow Length: Longer shafts are naturally more flexible. For every inch you add to a shaft, the effective stiffness decreases.
Point Weight: Heavier tips (125gr, 150gr+) increase the "Front of Center" (FOC) and cause the arrow to flex more upon release.
Bow Speed: Modern high-IBO compound bows transfer energy more aggressively than recurve bows, demanding stiffer shafts.
Victory Spine Chart Reference
Victory Archery typically categorizes their shafts (like the VAP, VForce, or RIP) into specific spine ratings. Use the table below as a general guide for standard 28″ arrows with 100gr points:
Draw Weight (lbs)
Recommended Spine
30 – 40 lbs
600 Spine
40 – 50 lbs
500 Spine
50 – 60 lbs
400 Spine
60 – 70 lbs
350 Spine
70 – 80 lbs
300 Spine
80+ lbs
250 Spine
Common Example Calculations
Example 1: A hunter using a 70lb compound bow with a 29-inch arrow and a 125-grain broadhead. Even though the chart says 350, the extra length and tip weight would push the requirement to a 300 spine.
Example 2: A target archer with a 45lb recurve bow and a 27-inch arrow. The shorter length increases effective stiffness, allowing the use of a 600 spine arrow for better flight characteristics.
Pro Tip: If your calculation falls exactly between two spine sizes, Victory Archery experts generally recommend choosing the stiffer (lower number) spine for compound shooters, as it is easier to tune than a shaft that is too weak.
function calculateSpine() {
var bowType = document.getElementById("bowType").value;
var drawWeight = parseFloat(document.getElementById("drawWeight").value);
var arrowLength = parseFloat(document.getElementById("arrowLength").value);
var pointWeight = parseFloat(document.getElementById("pointWeight").value);
var resultArea = document.getElementById("resultArea");
var spineValue = document.getElementById("spineValue");
var spineDesc = document.getElementById("spineDesc");
if (isNaN(drawWeight) || isNaN(arrowLength) || isNaN(pointWeight)) {
alert("Please enter valid numbers for weight, length, and point weight.");
return;
}
// Calculation Logic
// Base weight is the starting point
var effectiveWeight = drawWeight;
// Length Adjustment: Standard is 28 inches.
// Add 5lbs for every inch over 28, subtract 5lbs for every inch under 28.
var lengthDiff = arrowLength – 28;
effectiveWeight += (lengthDiff * 5);
// Point Weight Adjustment: Standard is 100 grains.
// Add 3lbs for every 25 grains over 100.
var pointDiff = pointWeight – 100;
effectiveWeight += (pointDiff / 25) * 3;
// Bow Type Adjustment
if (bowType === "compound") {
effectiveWeight += 10; // Aggressive cams need more stiffness
} else if (bowType === "recurve") {
effectiveWeight -= 10; // Fingers/Recurve need more flex
}
var recommendedSpine = "";
var message = "";
if (effectiveWeight > 82) {
recommendedSpine = "250";
message = "Your setup requires maximum stiffness. Consider Victory VAP or VForce in 250 spine.";
} else if (effectiveWeight > 72) {
recommendedSpine = "300";
message = "Heavy-duty setup. A 300 spine provides the necessary structural integrity for high energy transfer.";
} else if (effectiveWeight > 62) {
recommendedSpine = "350";
message = "Standard high-performance hunting setup. 350 is a very versatile Victory spine.";
} else if (effectiveWeight > 52) {
recommendedSpine = "400";
message = "Ideal for mid-range draw weights. Ensures excellent speed and kinetic energy.";
} else if (effectiveWeight > 42) {
recommendedSpine = "500";
message = "Suited for lower poundage or traditional setups. Promotes proper arrow paradox.";
} else if (effectiveWeight > 32) {
recommendedSpine = "600";
message = "Lightweight setup spine. Great for target archery or youth setups.";
} else {
recommendedSpine = "700 – 800";
message = "Low poundage setup. Look into Victory's specialized lightweight or junior shafts.";
}
spineValue.innerHTML = recommendedSpine;
spineDesc.innerHTML = "Calculated Effective Weight: " + effectiveWeight.toFixed(1) + " lbs equivalent." + message;
resultArea.style.display = "block";
}