In this study, the friction forces between a slider and disk surface with different lubricant thicknesses were measured at touchdown. Touchdown measurements of the friction and adhesion forces on a disk were made using a pin-on-disk tribotester. The friction force at touchdown could not be explained by a monotonic behavior, where the friction force gradually decreased with the lubricant thickness. Based on a comparison of the results measured using the pin-on-disk tribotester, it was estimated that the optimal adhesion force and a lower friction force are needed for the surfing regime at touchdown.Index Terms-Dynamic flying height (DFH), hard disk drive, head-disk interface, magnetic disk, pin-on-disk test.