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1/2" Constant Force Balance Coil Spring D, 6 lb – Amesbury Truth
- Regular price
- $3.25
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- Sale price
- $3.25
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1/2" Constant Force Balance Coil Spring D, 6 Pound This 1/2" (12.7mm) constant force balance coil spring, type D, is rated for 6 pounds (2.7kg) of sash weight. It is a standard replacement spring c... -
DL #6 1/2" Constant Force Balance Coil Spring for Tilt Windows
- Regular price
- $5.15
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- Sale price
- $5.15
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1/2" Constant Force Balance Coil Spring DL #6 Pound This 1/2" (12.7mm) constant force balance coil spring is designed for use in double- and single-hung tilt windows that rely on balance systems to... -
Stamped A 1/2" 3 lb Constant Force Balance Coil Spring
- Regular price
- $5.15
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- $5.15
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1/2" Constant Force Balance Coil Spring A - 3 Pound This 1/2" constant force balance coil spring is designed for use in window sash support systems, specifically for sash weights requiring 3 pounds... -
Triple Coil Support Cover, 1-1/4" Pocket, White, Squared Edge
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- $1.89
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- $1.89
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Support Cover for Triple Coil Constant Force Balance – 1-1/4" Pocket, White This support cover is designed for window applications using a constant force balance system with three coils. It is espe... -
4.5 lb 1/2" Coil Spring Universal Window Balance 1-1/4"
- Regular price
- $3.90
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- $3.90
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Coil Spring 1/2" Constant Force, 4.5 lb, 1-1/4" Universal Window BalanceThis universal constant force coil spring is designed for use in single or double hung sliding windows with a 1-1/4" (31.8mm)... -
983 Series Dual Coil Spring Support Cover for Simonton Windows
- Regular price
- $2.13
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- $2.13
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Support Cover for 983 Series Dual Coil Spring Balances This support cover is designed for use with 983 Series dual coil spring window balances, commonly used in Simonton windows and compatible with... -
Support Cover for Dual Coil Spring, 1-1/4" Pocket – White
- Regular price
- $0.99
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- $0.99
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Support Cover for Dual Coil Spring, 1-1/4" Pocket – WhiteThis support cover is designed to fit dual coil spring assemblies in 1-1/4" (31.8mm) pockets. Its clean white finish blends seamlessly with ... -
Omega 985 Centurion 3/4" Constant Force Coil Balance, 3.5–13.5 lbs
- Regular price
- $2.21 - $6.30
The Omega Series Centurion Coil Balance is a 3/4Inch wide stainless steel spring coil, used with constant force balance system.The unique design allows multiple coils to be interlocked to easily ac... -
985 Series 3/4" Constant Force Coil Balance for Vinyl Windows
- Regular price
- $16.33
Pre-Assembled 985 Series Centurion constant force balance assembly with 3/4 inch thick coil spring.The 985 series universal single coil balance with metal spring clip side locking brake fits single... -
Amesbury 985 Series 3/4" Spring Clip Brake Shoe – Side Locking
- Regular price
- $1.67
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- $1.67
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Amesbury 985 Series 3/4" Brake Shoe – Spring Clip, Side Locking The Amesbury 985 Series Brake Shoe is a replacement part designed for use in heavy-duty single hung and double hung vinyl windows. Th... -
3.5 lb 1/2" Universal Constant Force Window Balance Coil, 1-1/4" Pocket
- Regular price
- $3.90
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- Sale price
- $3.90
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Coil Spring 1/2" Constant Force, 3.5 Pound, 1-1/4" Universal Window Balance Coil This universal constant force coil spring balance is designed for single or double hung sliding windows that feature... -
Brake Shoe 4.610.108 for 1-1/4" Pocket Window, Pivot Lock, White
- Regular price
- $2.34
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- $2.34
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Brake Shoe for 1-1/4" Pocket Window, Pivot Lock – Standard Material This brake shoe is designed for use with 1-1/4" (31.8mm) pocket windows and features a pivot lock mechanism. Manufactured from st...
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Constant force coil balances, also known as window coil spring balances or coil spring window balances, are precision-engineered hardware designed to counterbalance the weight of window sashes. By using a flat, coiled stainless steel spring mechanism, these balances provide consistent tension throughout the full range of window motion, making it easy to lift, lower, and position windows safely and securely. They are widely used in vinyl and aluminum double-hung or single-hung windows for homes, apartments, and light commercial spaces.
How Constant Force Coil Balances Work
The constant force coil spring inside the balance cassette stores and releases energy as the window sash moves, delivering a steady opposing force to the sash weight. This ensures the window remains open at any position and closes smoothly, preventing sudden drops and reducing wear on window frames. Unlike older cord-and-weight or spiral balances, constant force mechanisms have no ropes or pulleys to fray or jam, resulting in a low-maintenance, longer-lasting solution. The stainless steel construction resists corrosion, making these balances reliable even in humid or coastal environments.
Use Cases and Compatibility
These coil balances are a go-to solution for window coil balance replacement in modern vinyl and aluminum window styles, especially where a slim, durable balance is required. They are commonly found in sash windows from popular brands and are suitable for both residential and light commercial applications. Each balance is chosen based on sash weight, window dimensions, and manufacturer guidelines. For replacement, always match the coil stamp or strength marking on your old balance to ensure proper function. Options like the PivotTrue® single coil or 984 Series dual coil are designed to fit a wide variety of window types and weights.
Features & Specifications
- Made of high-tensile stainless steel for durability
- Compact, corrosion-resistant design for vinyl and aluminum windows
- Consistent tension across full window travel
- Available in multiple strength ratings (e.g., 3 pound, 6 pound, 7 pound, 8 pound) to match specific sash weights
- Compatible with many leading window brands and models
- Easy to identify with coil stamp or part number for precise replacement
Replacement & Installation Tips
When replacing a window coil spring balance, always check the weight rating (coil stamp) and pocket width to select the correct part. Balances may be installed individually or in pairs, and correct installation is vital for proper sash support and safety. Many homeowners and professionals choose parts like the 985 Series tandem coil for medium-weight sashes or the 7 pound coil spring replacement for windows requiring extra lift. Accessories such as brake shoes and support covers are often replaced at the same time to ensure smooth operation.
About AmesburyTruth Genuine Parts
TruthParts is an authorized retailer of AmesburyTruth window hardware, guaranteeing that every constant force window balance, coil spring, and accessory is made to the original manufacturer's specifications. Choosing genuine AmesburyTruth parts ensures compatibility, lasting performance, and manufacturer-backed quality for every repair or upgrade.
Frequently Asked Questions
- How do I find the correct coil balance for my window?
Identify the coil stamp on your current balance or measure the sash weight and pocket width. If unsure, consult your window's documentation or contact us for expert advice. - Can I replace window coil balances myself?
Many homeowners can replace coil balances with basic tools and safety precautions. Detailed guides are available, but when in doubt, consider hiring a professional. - Are coil balances compatible with all vinyl windows?
Most modern vinyl and aluminum windows use constant force coil balances, but always match the size, weight rating, and type before ordering replacements. - What are signs my window coil balance needs replacement?
If your window is hard to open, won't stay up, or drops unexpectedly, the balance coil may be worn out and should be replaced for safe operation.
























