Extension springs are mounted horizontally along the upper horizontal tracks on either side of the garage door. Unlike torsion springs which store energy by twisting, extension springs operate through linear elongation. As the garage door closes, the springs physically stretch along the length of the track toward the back wall, storing kinetic tension that assists in lifting the door back open.
The Catastrophic Projectile Hazard of Uncontained Springs
Because extension springs stretch under immense linear tension, a spring fracture releases kinetic energy like an uncoiling steel whip. If an extension spring breaks without a heavy steel safety containment cable running through its core, the fractured coil can launch through the garage at speeds exceeding 60 miles per hour. Uncontained broken springs routinely shatter vehicle windshields, punch holes through drywall into living quarters, or cause catastrophic personal injury.
At TorsionCraft, our standard operating protocol for every extension spring repair includes the mandatory installation or inspection of 7x19 galvanized aircraft steel safety containment cables. Anchored securely to the rear horizontal track hanger and front wall angle, these cables keep the fractured spring safely captive if a coil ever breaks in the future.
Official DASMA 102 Color-Coding Weight Calibration
Extension springs must be calibrated to the exact physical weight of your garage door. Installing mismatched extension springs will cause one side of the door to drag, pulling the panels out of square and destroying track rollers. The Door & Access Systems Manufacturers Association (DASMA Standard 102) establishes a strict industry color code painted on the spring ends to identify weight capacity:
| DASMA 102 Spring Color Code | Single Door Weight Capacity | Double Door Weight Capacity | Common Application |
|---|---|---|---|
| White | 100 lbs | 200 lbs | Lightweight non-insulated single-car steel |
| Green | 110 lbs | 210 lbs | Standard single-car steel door (8x7) |
| Yellow | 120 lbs | 220 lbs | Single-car door with glass window inserts |
| Blue | 130 lbs | 230 lbs | Insulated single-car steel door (9x7) |
| Red | 140 lbs | 240 lbs | Heavy-gauge insulated single-car door |
| Brown | 150 lbs | 250 lbs | Standard uninsulated double-car door (16x7) |
| Orange | 160 lbs | 260 lbs | Double-car door with top window panels |
| Gold | 170 lbs | 270 lbs | Double-car insulated steel door (16x7) |
| Light Blue | 180 lbs | 280 lbs | Heavy 3-layer sandwich double-car door |
| Tan | 190 lbs | 290 lbs | Custom wood overlay or carriage house door |
Pulley Sheave & Cable Inspection
Extension spring systems utilize four heavy-duty ball-bearing pulleys (sheaves): two stationary pulleys mounted near the front wall and two movable pulleys attached to the springs. Over years of cycling, the cable grooves inside stamped steel pulleys wear down, developing sharp burrs that fray aircraft lift cables. Every TorsionCraft service call includes a thorough inspection of all pulley bearings, replacing worn sheaves with case-hardened ball-bearing units for whisper-quiet travel.
| Counterbalance Service Package | Estimated Cost | Standard Cycle Rating | Warranty Coverage |
|---|---|---|---|
| Single Torsion Spring Replacement Lightweight single-car doors (8x7, 9x7) |
$150 – $220 | 10,000 Cycles (~5-7 Yrs) | 3-Year Parts & Labor |
| Dual Torsion Spring Replacement Matched pair for double-car doors (16x7, 18x7) |
$240 – $360 | 10,000 Cycles (~5-7 Yrs) | 5-Year Matched Warranty |
| High-Cycle Commercial Conversion ASTM A229 oil-tempered heavy-wire upgrade |
$320 – $460 | 25,000 – 50,000 Cycles (15-20 Yrs) | Lifetime Warranty Option |
| Lift Cable Replacement & Drum Timing 7x19 galvanized aircraft steel cables (pair) |
$85 – $140 | Rated to 2,000 lbs | Full Replacement Warranty |
| Full Counterbalance Overhaul New springs + end bearings + center bushing + cables |
$380 – $540 | 25,000+ Cycles | 10-Year Comprehensive |