Garage Door Torsion Spring Turn Calculator
WARNING: Working with garage door torsion springs is extremely dangerous. High tension can cause severe injury or death. This calculator is for educational estimation only. Always consult a professional.
Recommended Setup
Total Full Turns
0
Quarter Turns
0
Understanding Garage Door Spring Tension
If you are wondering "how many turns on a double spring garage door calculator," the physics follows a relatively simple rule of thumb: One full turn for every foot of vertical door height, plus a small amount of preload.
The Standard Rule for Torsion Springs
Standard residential garage doors are typically 7 feet or 8 feet tall. The industry standard calculation for a standard lift torsion spring is:
- 7 Foot Door: 7.5 to 8 full turns.
- 8 Foot Door: 8.5 to 9 full turns.
When using a double spring system, each spring must be wound the same number of times. For example, if your door requires 7.5 turns, you must wind the left spring 7.5 turns and the right spring 7.5 turns. This balances the torque across the shaft.
Why the Extra Half-Turn?
The "plus 0.5" turn (or two quarter turns) is applied as a "preload." This ensures that when the door is in the fully open position, there is still enough tension to keep the cables tight on the drums. Without this preload, the cables could slip off, causing the door to crash or become stuck.
Practical Example
If you have a 7-foot tall door with a double spring setup:
- Total Height = 7 Feet.
- Base turns = 7.
- Recommended Preload = 0.5 turns.
- Final Result: Wind both the left and right springs exactly 30 quarter-turns (which equals 7.5 full turns).
Note: Winding bars should always be used. Most professionals count by quarter-turns because widing bars are swapped in 90-degree increments. 30 quarter turns = 7.5 full rotations.