Also known as a dial indicator or dial gauge, a dial test indicator (DTI) is a device used in various automotive applications where small distances need to be measured accurately, such as checking runout on brake disks or end float on a crankshaft.

Runout can quickly ruin a disk if it exceeds the manufacturer's specified tolerance (typically 0.15mm or less). So a dial test indicator is used when fitting a new brake disk to check the axial runout that occurs when the disk is rotated.

In the case of a crankshaft, a dial test indicator is used to make sure that the clearance between the machined faces on the crankshaft and the thrust faces of the thrust bearing are just right to permit proper lubrication and allow for thermal expansion. If the clearance is too small, there's the risk of seizure; if it's too great, lubrication make fail because of loss of oil pressure. A lever is positioned to move the crankshaft to and fro in order that the DTI can check the end float.