Bow String Stretch and Replacement Calculator
Track bow string stretch from shot count, draw weight, and material.
Get FPS loss estimate and replacement schedule for compound, recurve, and longbow strings.
Bow String Stretch and Replacement
A bow string stretches from repeated draw cycles. Stretch shifts brace height, peep rotation, and arrow speed. Most archers replace strings at 15-25% of total estimated life for competition tuning, or at end-of-life (50-70% stretch) for casual shooting.
Estimated string life by material (compound bow):
| Material | Shots Until Replace | Notes |
|---|---|---|
| Dacron (B-50) | 2,000-3,000 | Most stretchy, used on entry-level recurves |
| Fast Flight Plus / FF+ | 5,000-8,000 | Good stretch resistance |
| BCY 452X | 6,000-10,000 | Industry standard for compound |
| BCY-X / X99 | 8,000-12,000 | Premium, low creep |
| Trophy / Force-10 | 10,000-15,000 | Top-tier tournament strings |
Recurve / longbow strings:
| Material | Shots |
|---|---|
| B-50 Dacron | 2,000-3,000 |
| FastFlight | 4,000-7,000 |
| 8125 / D97 / DynaFlight | 5,000-8,000 |
Draw weight effect on lifespan:
- Heavier draw = faster stretch
- Each 10 lb above 50 lb draw cuts life ~10-15%
- Compound stops carry ~50% string load; recurve and longbow carry full load
Climate effect:
- High humidity (>70% RH): -15% lifespan (silicone wax breaks down)
- Hot car / direct sun storage: -25-30%
- Stored in cold dry case: 1.0× baseline
Speed loss from stretch (rough estimate):
| Stretch State | FPS Loss |
|---|---|
| New (under 5% life) | 0 fps |
| Broken in (5-25%) | 1-3 fps |
| Mid-life (25-50%) | 3-6 fps |
| Aged (50-75%) | 6-10 fps |
| End-of-life (75%+) | 10-15 fps |
Visual replacement signals:
- Visible fuzz / fraying along the served loops
- Wax flaking off (rewax monthly to prevent)
- Peep sight rotated more than 5° from original setting
- Brace height dropped more than 1/8 inch
- “Twang” or harsh hand shock on release
Maintenance to extend life:
- Wax weekly with proper string wax (BCY, BowJax)
- Avoid dry firing — single dry-fire can kill a string instantly
- Inspect serving — protect the string from rest contact
- Store at 50-70°F, away from direct sun
- Replace yokes / cables at the same time as the string for compounds
Tournament archer tip: keep two identical strings — rotate them so neither sees more than 50% of total shots before replacement. Backup string for emergencies.