A 12 radius has a sharper track curve and opens lower.
Garage door track radius measure.
Anything shorter than 91 inches is a 12 track radius.
Anything between 91 93 inches is a 15 track radius.
Nearly all residential garage doors have a track radius of either 12 or 15.
One quick rule of thumb in finding out what you have is to measure the height of the track stopping at the bottom.
Look for general irregularities such as jambs which are not square.
There are five basic garage door track options although the first two are by far the most common ones used in residential installations.
Step 1 measure the width of the opening at the widest point.
For best results the inside of the garage door opening should be framed with 2 x 6 wood.
This is the distance between the right and left sides of the finished opening.
A sharper curve exists on the 12 inch radius and it opens lower than the 15 inch version.