Wall Thickness Measurements of Rubber Tires and Bladders
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 Tire manufacturers often need to know total wall thickness or distance to steel or fiber ply cords in many types of rubber tires. With ultrasonic gauges it is now possible to measure thickness of rubber nondestructively and efficiently. It is done by coupling ultrasound into the tire from the outside surface. The ultrasound will normally be reflected from a steel or fiber ply cord, in
which case the gauge measures cord depth, or - in the absence of cords - it will be reflected from the inside surface of the tire. With the appropriate sound velocity setting for the rubber, the gauge then digitally displays the thickness of the rubber.
Because many types of rubber are very attenuating to high frequency ultrasound, it may be difficult to measure total wall thickness or cord depth in certain thick-walled and large diameter tires. External configurations and internal tire structures may further complicate ultrasonic thickness measurements.
Equipment: Depending on the application, there are a number of possible approaches to rubber tire thickness measurements. For automobile and light truck tires, position of the embedded steel or ply cord can be gauged with the
Model 35DL-HP or 35HP. These gauges in combination with a M1036 or M103
contact transducer will generally measure from 0.125 to 1.0 inches (3 to 25mm), to a calibrated accuracy of approximately ±0.010 inch (±0.25mm) or better.
If the distance to the steel belt or fiber ply cord is greater than 1 inch (25mm), it may be possible to use the Model 25DLHP with a M2008 transducer. This combination generally has enough sensitivity to penetrate up to several inches in rubber
We have available other instrumentation for special tire applications. For example, it is possible to measure tread thicknesses up to 8 inches (400mm) in off-road tires with a special ultrasonic system based around an
Epoch 4 flaw detector.
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