What Is Permanent Tire Flat-Spotting?

Have you noticed that during a straight-line panic stop, a driver's pressure on the brake pedal can be so intense it locks up the brakes and causes the vehicle to skid?

One stop with the brakes locked will wear a flat-spot in the tread that will render a tire unserviceable.

Panic stops conducted with vehicles not equipped with an Anti-lock Braking System (ABS) typically have two lasting side effects: long skid marks on the pavement and tires that have been permanently flat-spotted as their treads sacrificed themselves stopping the vehicle.

Locking up the brakes should never be the driver's intention since it surrenders directional control and results in longer stopping distances. However, the surprising circumstances of the moment may dictate otherwise. And it's far less expensive to replace a set of tires than pay a collision shop to repair the damage to the vehicle.

The other cause of flat-spotted tires is if the car slides sideways or spins out. If the tires aren't turning, the lateral movement of the tire grinding against the pavement will result in a flat-spot.

Minimizing Flat-Spotting (Braking With Non-ABS Equipped Vehicles)

Threshold braking is a high-performance driving technique that permits a driver to slow a vehicle at its optimum rate by pressing on the brake pedal just hard enough to hold the tires at their limit of traction before they begin to slide. Not allowing tires to uncontrollably skid across the road reduces stopping distances and helps the driver maintain directional control, as well as reduces how much the tread is ground against the road.

If brake lock-up is detected, slightly releasing a little brake pedal pressure and/or pumping the brakes will help the driver regain directional control.

Anti-Lock Braking Systems (ABS)

By automatically intervening to prevent tires from locking up and to avoid uncontrolled skidding, an anti-lock braking system (ABS) allows tires to maintain rolling contact with the road surface when braking. ABS protects tires from flat-spotting by rapidly and repeatedly pumping the brakes faster than humanly possible. In addition to reducing tire damage, ABS offers improved vehicle control and generally decreases stopping distances on slippery roads.

We disabled the ABS on our test car to demonstrate the longer stopping distances and reduction in vehicle directional control associated with brake lock-up.

If a panic stop situation arises when driving a vehicle equipped with ABS, it is common to feel the brake pedal pulsating. Drivers should never pump the brakes and must maintain firm brake pedal pressure until the vehicle has stopped completely.

A properly operating ABS will prevent tire flat-spotting.