Figure 3.9. Wheel Having Thin Flange Defects With Gage in Place.
b. Seams. One of the most serious wheel defects is a seam or
lengthwise crack in the tread. When a seam is located close to the flange,
it can cause the flange to break off the wheel. If a seam is detected
within 3 3/4 inches of the flange, the wheel must be removed. Figure 3.10
shows a wheel with a seam within the condemnable limit.
Figure 3.10. Wheel With Seam Defect.
c. Slid flat. A violent application of the brakes locks the wheels
causing them to skid along the rails. Such skidding results in worn flat
spots on the wheel treads called slid flat spots. If a wheel tread has a
slid flat area 2 1/2 inches or more in length, the wheel must be replaced.
If the wheel has two or more adjoining slid flat spots each 2 inches or more
in length, the wheel is condemnable. Passenger car wheels must not have
slid flat spots in excess of