Recurve Arrow Spine Selector
ALR-based recommendation · Finger release · 1″ insert depth · Nearest standard spine
Physics-based selection — applicable to all manufacturers. Spine is determined by draw weight, arrow length, and point weight.
Method
Axial Load Ratio
Target ALR 1.9 — Archer's Paradox
Target ALR 1.9 — Archer's Paradox
ALR band →
< 1.3 Very stiff
1.3–1.85 Stiff
1.85–1.95 Paradox target ✓
1.95–2.5 Underspined
2.5+ Dangerous
Cell: SPINE — ALR · Fit
1
Find your draw weight row — left column in pounds, measured at your full draw length with your recurve.
2
Follow across to your arrow length — carbon shaft only, nock groove to end of shaft. Does not include the protruding point.
3
This chart shows ideal values for a perfectly tuned setup. Axial recommends starting slightly weak — ALR 1.95–2.0 — then bare shaft tuning stiffer by cutting shorter or reducing point weight until flight cleans up. Orange = tunable to ideal. Blue = too stiff in this combination. Start with a different combination — often a longer arrow.
ALR formula: Applied force = draw weight × 0.90 (finger release factor) × √(point ÷ 100). Buckling force = 8,757,000 ÷ (spine × eff. length²). Effective length = shaft length − 1″ insert depth.
Each cell shows the nearest standard spine to ALR 1.9. Color reflects the actual ALR that spine produces. Non-green = no standard spine hits the 1.85–1.95 Paradox window for that combo. Adjust arrow length or point weight. Fit label: Stiff / Ideal / Weak.
Each cell shows the nearest standard spine to ALR 1.9. Color reflects the actual ALR that spine produces. Non-green = no standard spine hits the 1.85–1.95 Paradox window for that combo. Adjust arrow length or point weight. Fit label: Stiff / Ideal / Weak.
axialbowstrings.comFull calculator & recurve ALR article online