Ever seen archers hold drawn bows for ages? The secret is “let-off,” a game-changing feature in compound bows. This clever mechanism has transformed archery gear, boosting accuracy and endurance for all skill levels.
Let-off is unique to compound bows. It reduces the weight held at full draw compared to peak draw weight. This reduction ranges from 60% to 90%, expressed as a percentage.
Let-off has revolutionized archery equipment. It allows hunters to aim longer without tiring, improving their chances of success.
Compound bows have evolved since Holless Wilbur Allen invented them in 1966. Today’s adult models boast 40-80 pound draw weights and can shoot arrows at speeds of 250-370 feet per second.
Modern compound bows typically offer 65-80% let-off. Some high-end models even achieve over 90% let-off. This technology continues to improve, enhancing archer performance.
In 2017, PSE’s Evolution Cam introduced a 90% let-off. With this, a 70-pound bow only requires holding 14 pounds at full draw. This dramatic reduction significantly improves stability and accuracy.
Table of Contents
Key Takeaways
- Let-off is a unique feature of compound bows, reducing hold weight at full draw
- Typical let-off percentages range from 60% to 90%
- Higher let-off allows for longer hold times and improved accuracy
- Modern compound bows can achieve arrow speeds up to 370 feet per second
- Let-off percentages vary based on the bow’s intended use (hunting vs. target archery)
Understanding Compound Bow Mechanics
Compound bow mechanics changed archery forever. They offer greater efficiency and power than traditional bows. Let’s explore the key components that make compound bows unique.
Difference between compound bows and traditional bows
Compound bows differ greatly from traditional ones. They use cams, cables, and shorter limbs to generate energy. This design allows for faster arrows and better accuracy.
| Bow Type | Arrow Speed | Let-off | Energy Efficiency |
|---|---|---|---|
| Traditional Longbow | <200 fps | None | Lower |
| Compound Bow | Up to 370 fps | Up to 80% | 87-89% |
The role of cams and cables
Cams and cables are vital to compound bow mechanics. They create the let-off effect, a key feature in these bows. Let-off allows archers to hold less weight at full draw.
This advantage enables longer hold times and more precise aiming. The let-off typically ranges from 65% to 80%.
Energy storage in compound bows
Compound bows store energy better than traditional bows. Their efficiency rate of 87-89% outperforms even modern cars. This high efficiency leads to faster arrows and more kinetic energy.
Compound bows are popular for both target archery and hunting. Understanding their mechanics is crucial for improving archery skills. The system offers a customizable experience for different preferences and styles.
What is Let-Off in Compound Bows?
Compound bow let-off is a key feature that sets these bows apart. It reduces draw weight at full draw. This lets archers hold steady longer, boosting accuracy and cutting fatigue.
Let-off is shown as a percentage of reduced peak draw weight. For example, 80% let-off on a 60-pound bow means 12 pounds at full draw. This big drop is why many archers, especially hunters, love compound bows.
Let-off has changed a lot since the 1970s. Back then, bows had 35-40% let-off. Now, modern bows offer up to 80% or more. This has made archery easier for all skill levels.
Different archers prefer different let-offs. Bowhunters like 75-80% for steady aim when waiting to shoot. Target archers often choose 65% for balance between stability and string tension. Learn more about let-off importance here.
Let-off is crucial when picking a compound bow. It affects your shooting, from hold weight to release. Many new bows have adjustable cams to fine-tune let-off for your style.
How Let-Off Works: The Draw Cycle Explained
The draw cycle is a key feature of compound bows. It sets them apart from traditional bows. Let’s explore how let-off works and its impact on compound bow efficiency.
Peak Draw Weight
Peak draw weight occurs halfway through the draw. This is when you exert maximum effort. For example, a 70-pound bow requires 70 pounds of force at this point.
Valley and Holding Weight
As you draw further, the cams rotate, creating a “valley.” Here, the weight drops significantly, which is where let-off happens.
In the valley, you hold much less weight than the peak. For hunting bows, the holding weight is usually 20-25% of the peak.
Calculating Let-Off Percentage
Let-off is shown as a percentage. Here’s a simple formula:
Let-off % = (Peak Draw Weight – Holding Weight) / Peak Draw Weight * 100
Typical let-off percentages vary by bow type:
| Bow Type | Typical Let-Off | Example (70lb bow) |
|---|---|---|
| Hunting Bows | 75-85% | 17.5-10.5lb holding weight |
| Target Bows | 60-70% | 28-21lb holding weight |
| High Let-Off Bows | 90% | 7lb holding weight |
Let-off helps archers choose bows that fit their style. Higher let-off allows for longer holding times. This is great for hunting, where patience is key.
The Benefits of Compound Bow Let-Off
Compound bow let-off has improved archery. This feature makes shooting and hunting easier and more effective. Let’s examine why it’s so important.
The main benefit is less holding weight. Let-off ranges from 60% to 90%. This means archers can hold their bows at full draw more easily.
For example, with 60% let-off on a 70-pound bow, you’d only hold 28 pounds. This makes a big difference in comfort and performance.
Less holding weight leads to several advantages:
- Increased endurance during long hunting sessions
- Improved accuracy due to reduced muscle fatigue
- Ability to use higher peak draw weights for increased arrow speed and kinetic energy
- Enhanced stability and control at full draw
Let’s see how different let-off percentages affect holding weight:
| Let-Off Percentage | Peak Draw Weight (lbs) | Holding Weight (lbs) |
|---|---|---|
| 60% | 70 | 28 |
| 75% | 70 | 17.5 |
| 85% | 70 | 10.5 |
| 90% | 70 | 7 |
Compound bow let-off boosts both comfort and performance. Archers can hold proper form longer, leading to more accurate shots. This is especially helpful when hunting, where timing and patience matter.
Common Let-Off Percentages in Modern Compound Bows
Compound bow let-off varies based on use. We’ll compare hunting and target archery bows by their let-off percentages.
Hunting Bows: High Let-Off for Extended Hold Times
Hunting bows typically have higher let-off percentages. Modern bow hunting gear offers let-offs from 75% to 90%. These high let-offs help hunters hold bows at full draw longer.
In 2017, PSE made a compound bow with 90% let-off. This high percentage means hunters hold less weight at full draw. It reduces fatigue and improves accuracy when aiming at game.
Target Archery Bows: Lower Let-Off for Stability
Target archery bows usually have lower let-off percentages, from 60% to 70%. Competition archers often prefer these lower let-offs, which provide more holding weight at full draw and give steadier aim.
| Bow Type | Let-Off Range | Benefits |
|---|---|---|
| Hunting Bows | 75% – 90% | Extended hold times, reduced fatigue |
| Target Archery Bows | 60% – 70% | Increased stability, steadier aim |
Let’s compare a 70-pound draw-weight bow. With a 60% let-off target bow, an archer holds 28 pounds. A recurve archer with the same draw weight holds the full 70 pounds.
The Pope and Young Club now accepts entries with let-offs over 65%. They mark these with an asterisk in their records. This change, made in 2004, shows how compound bow technology affects hunting.
Let-Off and Bow Efficiency
Let-off is vital for compound bow efficiency. Modern bows usually have 80% let-off, reducing weight at full draw. A 70-pound bow with 85% let-off holds only 10.5 pounds.
Compound bows store more energy than traditional ones. They transfer about 84% of energy to the arrow. The rest becomes noise and vibrations. A typical setup can launch a 350-grain arrow at 287 fps.
Archers can boost efficiency in several ways. Using correct spine arrows and adding weights like speed nocks helps. Adjusting string strand count and end serving diameter also improves performance.
- Using arrows with the correct spine
- Shooting slightly heavier arrows
- Adding weights like speed nocks
- Adjusting strand count in the string
- Altering end serving diameter
These tweaks help transfer more energy to the arrow. The pulley system offers consistent shooting and a flatter trajectory, making compound bows great for hunting and recreation.
The Impact of Let-Off on Shooting Form and Accuracy
Compound bow let-off significantly affects archery performance. It influences shooting form and accuracy in various ways. Let’s examine how let-off impacts essential archery techniques.
Holding Stability at Full Draw
Higher let-off percentages boost stability at full draw. Archers can hold positions longer without tiring. This benefits hunters waiting for the perfect shot.
Target archers often prefer lower let-off, around 65-70%. It offers better control for precise shots.
String Tension and Deformation
Let-off affects string tension, impacting arrow launch consistency. Lower tension can increase string deformation. This can amplify form errors, making proper technique crucial.
Archers must consider these effects when adjusting let-off settings.
Face Pressure and Hand Torque Considerations
Higher let-off makes face pressure and hand torque more important. Due to reduced tension, small movements greatly impact arrow flight. Consistent form is vital to benefit from high let-off.
Understanding these nuances is key to mastering compound bow archery.
| Let-Off Percentage | Typical Use | Benefits | Considerations |
|---|---|---|---|
| 60-70% | Target Archery | Better control, stability | Requires more strength |
| 75-90% | Hunting | Longer hold times, less fatigue | May exaggerate form errors |
Choosing the Right Let-Off for Your Archery Style
Your archery style affects the compound bow let-off you choose. Hunters often prefer higher let-offs, from 75% to 90%. PSE’s Evolution Cam offers a 90% let-off, ideal for extended holding times.
Target archers usually choose lower let-offs between 60% and 70%. These percentages provide better control and stability during aiming. With a 60% let-off on a 70-pound bow, archers hold only 28 pounds at full draw.
When selecting a let-off, consider your strength, intended use, and comfort level. USA Archery and World Archery limit compound bow draw weight to 60 pounds in tournaments.
Try different let-off percentages to find your perfect balance. The right gear can greatly improve your shooting experience and results.
