(The Wahl correction factor accounts for additional stress in the material due to shear forces, although these forces do not contribute to the spring's torque. These shear forces become significant in designs using a low spring index, which is to say, a relatively thick wire for the coil diameter. The correction factor is applied to scale up the stress S to better predict the fatigue lifetime of the spring.)

Having a mismatched pair makes it difficult to specify the correct matched-pair replacements. To obtain replacement springs for a mismatched pair, you can either specify the same odd pair, try to calculate the equivalent matched pair sizes, or (this is the best method:) measure an accurate door weight and calculate the right spring size(s) "from scratch". The spring seller should be able to do the calculations from your accurate measurements of weight, height, and drum size; or you can attempt the calculations yourself using my engineering formulas below.
When a garage door goes off the track, the spring breaks, the door is dented or the garage door opener is on the fritz, a professional garage door repair specialist can help. The cost to have a garage door fixed varies, but the national average cost of garage door repair is \$70-\$110. The extent of the damage and the size and material of the door will affect the final cost. A garage door repair company generally charges a national average of \$80 for a service call, which includes the first hour of labor and service, such as testing and inspecting the garage door and opener. Apart from labor, the garage door repair costs hinge on buying replacements parts. For example, a new spring costs an average of \$60. Expect to pay several hundred dollars, though, if the door is beyond repair; a new garage door ranges in price from \$200 to \$4,000, and most homeowners spend an average of \$800-\$1,200.
Cable fail-safe redundancy: Based on the proper setting of the drums on the torsion shaft, the two lift cables divide the lifting force equally to keep the door level as it rises. This not only levels the door, but also provides a fail-safe mechanism. If one of the cables should fail, such as from breaking or losing its end attachment, the other cable will then carry the full weight of the door. This will pull the door up on one side with twice the normal force, while the other side falls from its now unsupported weight, tending to make the door bind in its tracks and jam. Although not foolproof, this is a safety feature of the design which keeps the door from falling catastrophically if a cable were to fail while the door was traveling. The jammed condition also prevents a lowered door from opening with the hazard of a single broken cable, further minimizing the chances of both cables failing. Since if one cable fails the other must sustain the full weight of the door, the cables and attachments are rated many times the normal working load of half the door weight. A proper safety inspection of the door should include a critical look at the cables and their attachments.

Roller doors ("Sheet Doors"-USA) are usually constructed of corrugated steel. They evolved from cover window and door coverings.[4] Other materials can be used (e.g.; transparent corrugated fibreglass) where strong impact resistance is not required. Corrugations give the door strength against impacts. A typical single car garage roller door has a preloaded spring inside the rolling mechanism. The spring reduces the effort required to open the door. Larger roller doors in commercial premises are not sprung (except USA) and use a manual pulley and chain system or a geared motor to raise and lower (roll up and roll down) the door. Roller doors cannot be effectively insulated.
Step 1: Check the metal tracks inside the garage. Look at the mounting brackets that hold the tracks to the walls. If they're loose, tighten the bolts or screws at the brackets. Working inside the garage with the garage door closed, examine the tracks for dents, crimps, or flat spots. If there are any damaged spots, pound them out with a rubber mallet, or with a hammer and a block of scrap wood. If the tracks are badly damaged, they should be replaced.
Most wood doors are sectional roll-up doors, though a swing-up wood door that’s meant to be painted can be affordably built in the driveway from a wood framework and plywood. Custom wood doors are typically made of durable softwoods such as Douglas fir, cedar, redwood or cypress, or from hardwoods such as oak or mahogany. Appearance-grade hardwoods are relatively expensive.
Sterling Door is the only company we trust with our garage door. When our old door acted up, springs, track, etc., they were always timely and got the job done. Then when we made the jump to a new door, they were excellent. They helped us choose the right door, not just pushing the most expensive model. And installation was well done. I recommend Sterling Door for all of your garage door needs.
Home Depot local Service Providers are background checked, insured, licensed and/or registered. License or registration numbers held by or on behalf of Home Depot U.S.A., Inc. are available at homedepot.com/licensenumbers or at the Special Services Desk in The Home Depot store. State specific licensing information includes: AL 51289, 1924; AK 25084; AZ ROC252435, ROC092581; AR 228160518; CA 602331; CT HIC.533772; DC 420214000109, 410517000372; FL CRC046858, CGC1514813; GA RBCO005730, GCCO005540; HI CT-22120; ID RCE-19683; IA C091302; LA 43960, 557308, 883162; MD 85434, 42144; MA 112785, CS-107774; MI 2101089942, 2102119069; MN BC147263; MS 22222-MC; MT 37730; NE 26085; NV 38686; NJ 13VH09277500; NM 86302; NC 31521; ND 29073; OR 95843; The Home Depot U.S.A., Inc. is a Registered General Contractor in Rhode Island and its Registration Number is 9480; SC GLG110120; TN 47781; UT 286936-5501; VA 2705-068841; WA HOMED088RH; WV WV036104; WI 1046796.

The wire size and winding direction are easily discovered and proved, as I will explain below. You absolutely must know and understand the critical measurements of your old springs to order replacements. This assumes that the old springs were the correct to begin with; it is not uncommon to have incorrectly sized springs on a door due to a previous sloppy installation, or a significant change in weight of the door.
Clopay Garage Doors featuring Intellicore insulation technology represent Clopay Garage Doors featuring Intellicore insulation technology represent the ultimate smart choice for homeowners. Clopay Intellicore is proprietary polyurethane foam that is injected into a garage door expanding to fill the entire structure. The result is a door with incredible strength and durability. Its dense insulation also produces a quieter ...  More + Product Details Close
Replace your old garage door and give your home a new look. Make it a custom garage door down to the tiny details. It's easy, fun and you can put together as many as you like before you get the perfect style for your home. Try our online customized garage door selector tool, and you'll have the garage door of your dreams on its way to you in no time. Standard, yet dependable wood-look steel doors, grooved-panel steel doors and classic raised panel steel doors are some of your options. Boost your style with barn garage doors for a unique, old-time yet modern look. Choose from hundreds of garage styles including traditional, carriage house and contemporary. If you spend time in the garage, let some light in, get a garage door with windows. The garage doesn't have to be just for cars, use the space however you need it - a play room for the kids, a workshop for hobbies, a studio. Let fresh air in but keep the bugs out with a garage door screen.