Don’t let a Bottom Roller GUARD Hinder your Undercarriage Inspection

The Guard prevents the inspector from using a caliper or a Ultrasonic Tool from completing the measurement of the Bottom Rollers, but they can be measured as follows: –

1. The dimensions from the center of the Bottom Roller shaft to the Shoe underside is made up of half the Roller Diameter + (Plus) the Link Height.
2. Thus, to calculate the diameter of the Track Roller by using the following formula from the image above:-
   1. Measure A being the distance from Bottom Roller Centre Pin to the Underside of the Shoe.
   2. Measure B being the Link Height
   3. The Track Roller diameter = 2 X (A – B)

1. How to measure B or the Link height with a Depth Gauge

place the Depth Gauge on the rail, and press the pin through to the underside of the Shoe just before the point of curvature of the Shoe. The use a ruler to measure the length of the Pin. This will provide the dimension of B