With the spreader in motion, the wheels should be observed for any indication of wheel wobble or excessive toe-in or toe-out. Any of these conditions will tend to cause the tires to scuff the aggregate. The spreader box is the first vehicle to drive over the freshly placed aggregate, and when the spreader’s tires pass over the aggregate, the aggregate particles will still be in unarranged positions. Any scuffing by the spreader’s tires may shove the aggregate sideways rather than straight downward. Scuffing will appear as a dark, ragged-looking strip causing asphalt to be picked up on the tires of the pneumatic rollers.

The tires should be checked to detect any gouges that might adversely affect the aggregate arrangement. Gouges that may weaken the sidewall could lead to a tire blowout. This type of faulty tire should be changed before the project starts.