In some cases, it may be possible to install a new garage door on existing tracks. However, it depends on several factors, including the compatibility of the new door with the old tracks and the condition of the tracks themselves. If the tracks are damaged, misaligned, or incompatible with the new door, they may need to be replaced as well. It is recommended to consult with a professional garage door installer who can assess the condition of your existing tracks and determine if they can be used with the new door or if replacements are necessary to ensure proper installation and functionality.