The information contained in this article is for guideline purposes only.
When looking over your PA Inspection invoice, you may have noticed the following under/beside the PA Inspection heading –
TIRES: LF (4) RF (5) LR (2) RR (5)
BRAKES LF (8B) RF (8B) LR (2R) RR (5R)
The information is not difficult to understand but can be helpful information when it is understood. All the numbers you see in parenthesis are measurements in 32nd’s of an inch. For example – the Left Front tire (LF) is 4/32″ of tread depth, measured at the least amount of tread depth on the tire. Compared to new tires of at least 12/32″ tread depth; having 4/32″ tread is not safe on wet roads. However, it does pass PA Safety Inspection Laws. Remember, this is not measured at the area of the most tread depth, but the least. Knowing the tread depth on your tires will help you plan replacement.
The brake measurements are in 32nd’s of an inch, but you will notice a B or R beside the depth measurement. The B represents (Bonded) lining, and the R represents (Riveted) brake lining. The R and B tell us how the brake lining is fastened to the brake backing plate. Why does this matter? The Riveted lining has a minimum measurement of 1/32″ of lining remaining, and the bonded lining is rejected when below 2/32″. Note that it does not matter what is remaining on the rest of the brake pad/shoe; the minimum determines pass or fail.
For comparison; new disc brake pads typically have approximately 12/32″ lining of bonded or riveted lining, while drum brakes have 4/32″ or 5/32″ in bonded or riveted lining. Knowing what is remaining on your brakes will help you gauge when the brakes need to be replaced before damaging the brake drum or brake rotor.
Note: The approximate new measurements are just that: approximate. Better tires or brakes can measure more or less.
Below is a picture of new brake lining. The one on the left is a Riveted Drum brake style and on the right is the Bonded Disc Brake Pad.
Quick Tip; When my auto registration application arrives, I am reminded it is time for the Annual PA Safety Inspection.