__ runout occurs when the component is bent or improperly manufactured and causes the wheels to jiggle side to side, creating a horizontal vibration that feels like a shimmy. a. Primary b. Secondary c. Radial d. Lateral

## Step 1<br />The problem is asking us to identify the type of runout that causes horizontal vibration in wheels when they are bent or improperly manufactured. <br /><br />## Step 2<br />Runout is a term used in engineering to describe the deviation from the ideal centerline of a component. This deviation can be caused by improper manufacturing or bending of the component.<br /><br />## Step 3<br />In the context of wheels, runout can cause horizontal vibrations, which can be felt as a shimmy. <br /><br />## Step 4<br />Among the options provided, lateral runout is the one that causes horizontal vibrations. Lateral runout refers to the deviation of the wheel from its ideal centerline in a side-to-side direction. This deviation can cause the wheel to jiggle side to side, creating a horizontal vibration that feels like a shimmy.