Garage door torsion system contains few ball bearings along its shaft/torsion bar. The bearing was invented and has been in use since ancient times. However, Philip Vaughan, a British inventor, is the first to record a patent on a modern ball bearing. With a ball running along a groove in an axle assembly, Philip Vaughan created the first design for a ball bearing in 1794, and it was the first recorded ball-bearing in the history of mankind.
When it comes to ball bearings, there are few types of constructions and designs, nevertheless, garage door torsion systems require flanged radial ball bearing which contains a flange/raised lip on the outer race. The flange is necessary for the positioning and mounting procedure of the ball bearing to its plate.
The Garage Door Bearing Construction
The garage door’s flanged radial ball bearing made out of steel and its design is pretty simple; it’s constructed from inner race/ring and a steel balls race covered by an outer race/ring. The inner part of the bearing contains the inner race, with an inner diameter of 1 inch to contain and support the torsion tube and its load. In motion, the inner race rotates, causing the bearings’ balls to rotate along.
The balls race separates the inner race from the outer race. The role of the balls in the ball bearing design is to reduce rotational friction, or in other words, to reduce rolling resistance which is the force resisting to the motion. Think about it this way, in motion, when the balls are rotating/rolling in between the races in some sort of buffer, the friction amount dropping substantially compared to two flat rings rubbing/rotating against one another.
The flanged outer race is located above the balls race. The outer race is stationary, and it’s the most external ring of the bearing which is also mounted to the end bearing plate and/or center bracket.
Now that we understand how garage door steel bearing is constructed and how it operates, we can understand how incorrect assembly affects the bearings and how faulty bearings can become a major safety issue which results in an unnecessary garage door repair. The garage door torsion system is equipped with 1 bearing for each end bearing plate and 1 bearing or garage door bushing for each center bracket (garage door bushing is a plain nylon bearing which provides bearing surface between the garage door spring stationary cone to the shaft/torsion tube). The garage door steel bearing will wear out and/or be damaged due to the following reasons:
- End bearing plates and/or center bracket misaligned vertically
- End bearing plates misaligned with the center line
In case the end bearing plates and/or center bracket aren’t leveled and/or mounted in different plains, the torsion tube will be resting in an angular/bow shape rather in a straight line. This misalignment results in an excessive force being applied to a given bearing. There are two types of misalignment:
- Offset or parallel misalignment (fig. 1).
- Angular misalignment (fig. 2).
Offset or Parallel Misalignment
When it comes to the garage door torsion systems, offset or parallel misalignment occurs when end bearing plates and/or center brackets are parallel to each other but are not placed on the co-planar/same plane. This can occur in both vertical plane and horizontal plane. In fig. 1 we can see how end bearing plates and center bracket that are mounted on different vertical plains, causing offset/parallel misalignment and the torsion tube to bow.
Angular misalignment occurs when the garage door end bearing plates and/center bracket aren’t mounted in a straight vertical line. In fig. 2, we can see how the end bearing plates and center bracket are slanted to the side, causing angular misalignment.
In both scenarios, offset/parallel misalignment and angular misalignment, there’s increased excessive force on the garage door shaft/torsion tube’s supporting components and on the torsion tube itself. Excessive force increases friction which decreases the lifespan of system components, such as garage door opener, hinges, rollers, springs, shaft, and bearings.
Bearings and Misalignment
When it comes to garage door bearings, misalignment that causing the shaft to bow will constantly apply an excessive force on the bearing’s inner race. Over time, the inner race will wear out and may come off its position (see fig. 3). Furthermore, due to excessive force on a given inner race’s wall, the rotational direction is damaged. Inaccurate rotation of the bearing’s inner race will grind the shaft (see fig. 4) until it eventually shears off, which is a major safety concern.
With lack of supportive components along the shaft, the garage door will come off its track or even worse, may detach from the torsion system and with no counterbalance, the garage door will crash down to the ground. Therefore, as garage door experts, when we perform garage door repair, garage door safety inspection or maintenance service, it’s our responsibility to make sure that the garage door torsion system is properly aligned and that the bearings are in good working order.