Arrow spine is one of the most misunderstood concepts in archery, yet it's crucial for accuracy. Shooting arrows with the wrong spine is like driving with misaligned tires—you can compensate, but you'll never achieve optimal performance. This guide demystifies spine selection.
📏 What is Arrow Spine?
Spine refers to the stiffness (or flexibility) of an arrow shaft. It's measured by how much the arrow bends when a weight is applied to its center.
Lower number = stiffer arrow. Higher number = more flexible arrow.
A "300 spine" arrow is STIFFER than a "500 spine" arrow. The number represents how much the arrow deflects (in thousandths of an inch), so lower = less bend = stiffer.
Understanding arrow spine: Too weak bends too much, correct spine flexes perfectly, too stiff barely bends
🎯 Why Spine Matters for Accuracy
When you release an arrow, it bends around the bow (called "archer's paradox"). The spine determines how much it bends and whether it recovers correctly in flight.
❌ Too Weak (Underspined)
- • Arrow bends too much on release
- • Arrows fly left (for right-handed)
- • Poor accuracy and erratic groups
- • Can cause arrow damage or breakage
❌ Too Stiff (Overspined)
- • Arrow doesn't flex enough
- • Arrows fly right (for right-handed)
- • Reduced forgiveness for form errors
- • Potentially wasted energy
✅ Correct Spine
- • Arrow flexes and recovers perfectly
- • Straight, consistent flight path
- • Tight, centered groups
- • Maximum energy transfer to target
⚙️ Factors That Affect Your Ideal Spine
Draw Weight
Higher draw weight = need stiffer spine. A 60lb bow needs much stiffer arrows than a 30lb bow.
Arrow Length
Longer arrows flex more. If you cut arrows shorter, they become stiffer. Add 1" = weaker; cut 1" = stiffer.
Point Weight
Heavier points = weakens dynamic spine. 100gr point shoots weaker than 80gr on the same shaft.
Bow Type
Compound bows need stiffer arrows than recurves at the same draw weight due to let-off mechanics.
📊 Quick Spine Selection Chart
Use this as a starting point. Always verify with your arrow manufacturer's specific chart.
| Draw Weight | Recurve Spine | Compound Spine |
|---|---|---|
| 25-30 lbs | 700-800 | 600-700 |
| 30-35 lbs | 600-700 | 500-600 |
| 35-40 lbs | 500-600 | 400-500 |
| 40-45 lbs | 450-500 | 400 |
| 45-50 lbs | 400-450 | 350-400 |
| 50-55 lbs | 350-400 | 340 |
| 55-60 lbs | 340-350 | 300-340 |
| 60-70 lbs | 300-340 | 250-300 |
🧪 How to Test If Your Spine is Correct
Bare Shaft Test
The most reliable method to check spine tuning:
- Shoot 3 fletched arrows at 20 yards - note grouping
- Shoot 3 bare shafts (no fletching) at same target
- Compare where bare shafts hit vs fletched arrows
Spine too weak
Spine correct! ✓
Spine too stiff
- • When in doubt, go slightly stiffer—you can always add point weight to weaken
- • Keep a consistent arrow length (mark your arrows)
- • Check manufacturer charts—each brand is slightly different
- • Your spine needs may change as your form improves
Is Your Form Affecting Your Arrows?
Inconsistent form can mask spine issues. Use ArcheryBuddy to perfect your technique before fine-tuning your arrows.
✅ Key Takeaways
- ✓Spine = arrow stiffness. Lower numbers = stiffer arrows
- ✓Draw weight, arrow length, and point weight all affect your ideal spine
- ✓Use manufacturer charts as a starting point, then fine-tune
- ✓The bare shaft test is the most reliable way to verify spine
