The retractable garage door is fast becoming the more popular type of up and over garage door mechanism in the UK, its name derived from the garage door panel retracting fully into the garage when open. It is the mechanism that will convert easily and safely into electric operation with the least equipment required. The drive-through width on a retractable mechanism is reduced as the lifting arms sit in between the sub-frame when the door is opened, be careful when limited for width that you do not restrict access too much.
The retractable mechanism can take much heavier loads with tension springs at the sides easily increased in size and strength. The best retractable doors have no cables internally for locking but locking rods made from steel. They also have multiple springs either side to spread the risk of spring failure and give an overall smoother action when lifting.
Retractable gear mechanism is used for garage doors over 8 feet wide and heavier garage door panels such as hardwood. All double garage doors have retractable gear only.