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)
This is not rocket science, 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 inch of tread depth, measured at the least depth on the tire. To give you a perspective of what is remaining, new tires have a least 12/32″ tread depth. Having 4/32″ is not allot of tread and is not real safe on wet roads, but 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.
Moving on to the brake measurements. Again the measurements are in 32nd’s of and inch, but you notice a B or R beside the depth measurement. The B represents ( Bonded ) lining and the R represents ( Riveted ) brake lining. This is telling us how the brake lining is fastened to the brake backing plate. Why does this matter? Riveted lining has a minimum measurement of 1/32″ of lining remaining and bonded lining is rejected below 2/32″ . Note, it does not matter what is remaining on the rest of the brake pad/shoe, it is the minimum that matters. For comparison; new disc brake pads normally have approximately 12/32″ lining in bonded or riveted lining, while drum brakes have approximately 4 or 5/32″ in bonded or riveted lining. Knowing what is remaining on your brakes, will help you gauge when the brakes should be inspected, so as not to score the brake rotor or drums.
Note: The approximate new measurements are just that: approximate. Better tires or brakes can measure more or less than.
Below is 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 type for the Annual Safety Inspection.