Abstract: A skid detector is mountable for rotation with a vehicle wheel to enable a driver of the vehicle, especially a tractor trailer, to observe a condition wherein the tire is skidding. The detector comprises a strip mountable to a hub of the vehicle and includes a pair of legs projecting outwardly beyond the plane of the tire side wall so as to be observable when the tire is viewed in a direction transversely of the rotary axis thereof. The legs carry a light reflecting substance so as to be visible at night. A fastener is provided which enables the strip to be mounted in a central hole of the vehicle hub. The legs are configured so as to be deformed in response to engagement with an annular wall of the wheel so as to assume a condition parallel to the rotary axis of the wheel.