A dial caliper is a precise measuring tool that can accurately measure the thickness of brake pads. It has two jaws that are closed over the brake pad and a dial that indicates the thickness. Dial calipers are available at most hardware stores.
A visual inspection is not as accurate as a dial caliper, but it can still be used to get a general idea of how much wear is on the brake pads. To do a visual inspection, look at the brake pads through the wheel spokes. If the brake pads are worn down to the metal backing, they need to be replaced.
Here is a comparison of the two methods:
| Gage | Accuracy | Pros | Cons |
|---|---|---|---|
| Dial caliper | Very accurate | Easy to use | Requires removal of the wheel |
| Visual inspection | Not as accurate | Does not require removal of the wheel | Can be difficult to see the brake pads |
