Every torsion spring garage door system uses bearings along the length of the torsion tube. These bearings are stamped into or supported by hardware in the middle by center support brackets, also designated "spring anchor brackets." These are secured with lag screws to the header. The end bearings are are usually stamped into the end bearing plates which are supported by the horizontal track angle with bolts and nuts, and sometimes also to the header with lag screws. If a bearing deteriorates and if you have an arbor press, it may be easier to replace just the bearing, but often it is better to replace the bracket along with the bearing.
There are two types of end bearing plates: supported and unsupported. The supported end bearing plates secure to both the angle on the horizontal track and to the garage header (pictured on the right and the left). The side of these end bearing plates is determined by the center line (CL) of the shaft offset. This is the distance from the center of the shaft to the garage header that is allowed by the bearing plate. The necessary CL is determined, for the most part, by the drum radius.
Unsupported end bearing plates secure only to the angle of the horizontal track and not to the garage header (pictured above and below). These bearing plates are weaker because they are not supported. In rear-mount garage doors where the springs are mounted toward the back of the garage, these bearing plates are sometimes the only option. Unsupported bearing plates are measured from their mounting position on the angle to the center line of the shaft (L).
We also offer end bearing plate kits for residential garage doors to help the homeowner ensure that he has all of the necessary hardware with the bearing plate.
Spring anchor brackets come slotted without the bearing attached or fixed with the bearing attached to the bracket. The slotted residental spring anchor bracket (SAB-450) the center line (CL) of the shaft to be offset from the garage header by up to 4-1/2". The slotted commercial spring anchor bracket (SAB-1000R) equivalent allows for greater shaft offsets corresponding to springs with an inside diameter of up to 6". The 6" slotted spring anchor bracket is best used to secure the outer 6" spring in a duplex assembly when the inner spring is longer.
Spring anchor brackets with fixed bearings are measured by the center line (CL) of the shaft to the garage header. This dimension is usually dependent on the end bearing plates, which are dependent on the cable drums used on the garage door. These brackets are often times also used as idler brackets to help support the shaft on wider doors and those with heavier torsion springs.
On the lighter residential doors, we also provide spring anchor bracket kits to ensure that you have all of the necessary hardware to install the bracket.