Note that I am measuring a spring that is fully relaxed because it is broken!. The length of the relaxed, unbroken spring is the specification of interest. It is harder to measure unbroken springs on an intact door because the springs should not fully unwind, even at the top-of-travel. If you can't be certain of the spring diameter from indications on the cones, then you have to go through an unwinding procedure to relax them fully for measurement, or perhaps reckon the size from measuring the somewhat smaller diameter at the nearly unwound condition when the door is at its top-of-travel (although one should not attempt to raise a door with a broken spring).
Horsepower is another key factor when it comes to garage door openers. Look into ½ horsepower garage openers if you have standard aluminum doors. Oversized doors and one-piece doors may require 3/4, 1 or 1¼ horsepower garage door openers. Garage openers with higher horsepower use less effort to operate and minimize wear and tear on the motor. This is ideal if your garage doors act as the main entrance to your home.
```Speed of a falling door:: Physics tells us that the transit time of a free-falling body is sqrt(2x/g), where x is the length of the fall and g is the acceleration due to gravity (32.2 ft/sec^2). If this typical 150 lb door were to fall an equivalent of 3.75 feet, this falling time would be sqrt(2*3.75/32.2) = 0.48 seconds (480 milliseconds). The terminal velocity is gt, or 0.48 seconds * 32.2 ft/sec^2 = 15.5 ft/sec = 10.6 mph.
```

Our reviewers tested a top-rated garage door opener daily for over a week. To get the most comprehensive results possible, they installed it themselves and observed how it performed. We asked our testers to consider the most important features when using this garage door opener, from its drive type to its security features. We've outlined the can’t-miss points here so that you, too, know what to look for when shopping.
```Here’s an opener that comes with all the bells and whistles. Featuring an ultra quiet belt drive, you’ll be thankful you purchased one like this especially if you have a room positioned near or above the garage. It’s also got battery backup so if the power goes out, you can still get in and out with ease for up to 20 open and close cycles for the first 24 hours of an outage. And for the technology savvy will appreciate its MyQ smartphone control technology that allows you to control the door via an app on your iPhone or Android, plus you’ll receive safety notifications if you’re away from the house and the door opens or closes. And for extra peace of mind, there’s also a feature that will automatically close the door after a set amount of time — you know, just in case you forget.
```

A garage door is a large door on a garage that opens either manually or by an electric motor (a garage door opener). Garage doors are frequently large enough to accommodate automobiles and other vehicles. Small garage doors may be made in a single panel that tilts up and back across the garage ceiling. Larger doors are usually made in several jointed panels that roll up on tracks across the garage ceiling, or into a roll above the doorway. The operating mechanism is spring-loaded or counterbalanced to offset the weight of the door and reduce human or motor effort required to operate the door. Less commonly, some garage doors slide or swing horizontally. Doors are made of wood, metal, or fiberglass, and may be insulated to prevent heat loss. Warehouses, bus garages and locomotive sheds have larger versions.
Tools in Action says the Ryobi Ultra Quiet has plenty of versatility, as you can plug devices into the opener hardware, like a Bluetooth speaker, a fan, or even an 18V Ryobi cordless tool battery. When the opener has power, it will charge the battery. But if your home ever loses power, the 18V battery works as a backup to the garage door opener, allowing it to operate normally.
Align the upper roller tracks by carefully lifting the door halfway. Lock it in place with two locking pliers, and install the supporting brackets on the back of the rails using 1-1/4 in. perforated angle iron (available at home centers and hardware stores). Install 1-1/2 x 1/4 in. stop bolts, with the threads to the inside of the track, at the end of each upper track.
Note the left winding cone with red spray paint. This shpritz of paint is applied to create fear and doubt in the mind of the do-it-yourselfer. Sometimes it is a color code for the wire size (using a DASMA standard, red indicating 0.2253 inch diameter wire). Sometimes it indicates the winding direction: red may indicate right-hand winding, but don't rely on that; do you own independent analysis. Sometimes it is a manufacturer's private code for another dimension than wire size. This color code is for the installer's information when the spring is new; I would not depend on interpreting the color code properly on an old spring, since one can't be certain of a correct interpretation without documentation from the original supplier.
The belt-driven Chamberlain B970 garage door opener is powerful and well-featured. With a 1.25 HPS motor, it's got all of the strength needed for just about any residential garage door, and the motor and belt are covered by a lifetime warranty. The feature line-up includes built-in Internet connectivity for those who want to be able to monitor and operate their opener from afar, and a battery back up in the case of a power outage.

With over 300 independently moving parts, your garage door is a deceptively complex piece of equipment. To help prevent malfunctions and break-downs, it is a good idea to occasionally perform a garage door tune-up to keep all of these parts in good working order. A regular tune-up service by a Sears professional can prevent unexpected door problems and prolong the life of your existing equipment.