What tool should be used to measure the brake pad thickness?

Using a caliper gauge to measure brake pad thickness is the most accurate and effective method for ensuring that the pads meet safety standards. A caliper gauge can give precise measurements, which is essential for determining whether the brake pads have sufficient material remaining for safe operation.

Brake pads typically have a specified thickness that indicates their effectiveness; if they wear down beyond this thickness, they may not provide adequate braking power, posing a significant safety risk. The precision of a caliper gauge allows you to measure small differences in thickness that could be critical for maintaining proper braking performance.

Other tools, like a penny or a ruler, do not provide the level of accuracy required for this task. A penny is sometimes suggested as a rough measurement tool for tire tread depth, but it isn't suitable for the precise measurement required for brake pads. A regular ruler lacks the specificity to measure the thin dimensions of brake pads accurately. Similarly, a screwdriver does not lend itself to measurement at all; it is not a measuring tool.