Track Radius

Track radius is the size of the arc in the horizontal radius section of garage door track. It tells you how much space the door needs above the opening in order to make the turn from vertical to horizontal travel. Service Spring defines it simply as the amount of space, in inches, needed for the door to transition from closed to open.

Think of it this way: a 12-inch radius means the centerline of the curved track follows a circle with a 12-inch radius. A 15-inch radius follows a larger circle. The larger the radius, the taller the loop, and the more headroom you need.

Standard sizes and when each is used:

• 12-inch radius: The most common residential size. Requires a moderate amount of headroom above the opening. Fits most standard garages.
• 15-inch radius: Used on heavier commercial doors and some residential setups with enough headroom. The gentler bend reduces stress on the panel joints.
• Low-headroom radius: A modified, flattened curve used when headroom is less than 10 inches. It requires special hardware and limits spring options.

For example, a 9-foot wide by 7-foot tall residential door on a garage with 11 inches of headroom uses 12-inch radius track. The bottom panel of the door enters the curve right at the top of the opening and is lying flat in the horizontal track within those 11 inches.

Track radius also affects roller wear. A tighter radius bends the panel joints more sharply on each cycle. Over 10,000 cycles that adds up. Doors with heavy glass sections or commercial-weight panels often spec 15-inch radius track to extend hinge and panel life.

Track radius is closely related to low headroom situations, where the available space above the opening determines which radius is possible.