Vehicle tire checks — Iowa Permit Test

Worn, bald, or unbalanced tires can increase your stopping distance and cause hydroplaning.

Tires with little tread cannot push water out of the way or grip the road, so the car slides farther before it stops.

Worn, bald, or unbalanced tires can increase your stopping distance, cause hydroplaning (See page 60), cause faster tire wear, reduce fuel economy, and make the vehicle harder to steer and stop.

If the vehicle bounces, the steering wheel shakes, or the vehicle pulls to one side, have a mechanic check it.

A shake or a pull often means a tire problem. Left alone, it can make the car hard to control at speed.

If the vehicle bounces, the steering wheel shakes, or the vehicle pulls to one side, have a mechanic check it.

Check tire air pressure with a gauge when the tires are cold.

Air in a tire swells as it warms up from driving, so a hot tire reads higher than it really is.

Check tire air pressure with an air pressure gauge when the tires are cold.

The recommended tire pressure is commonly listed on a sticker inside the driver's door or in the owner's manual.

Each car needs its own pressure. Too much or too little air makes the car harder to steer and stop.

The recommended tire pressure is commonly listed on a sticker inside the driver’s door or in the vehicle owner’s manual.

Check tread with a penny, head first: if the tread does not reach at least the top of Lincoln's head, the tire is unsafe and should be replaced.

Shallow tread cannot grip the road, most of all when it is wet. The penny is a quick way to measure it.

If the tread does not come at least to the top of Lincoln’s head, the tire is unsafe and should be replaced.

What can worn or bald tires do?

Increase your stopping distance. Tires with little tread cannot push water out of the way or grip the road, so the car slides farther before it stops. Iowa Driver's License Manual, p.24: “Worn, bald, or unbalanced tires can increase your stopping distance, cause hydroplaning (See page 60), cause faster tire wear, reduce fuel economy, and make the vehicle harder to steer and stop.”