Customers often tend to schedule tire changes at the same time
as mechanical maintenance… But watch out for leaks!!!
It is not uncommon to change oil and bleed hydraulic equipment during mechanical maintenance, but remember that exposure is extremely damaging to tires.
As part of an in-house experiment, we used a rubber block which we soaked in hydraulic oil without wiping it. The Duro (hardness index of the rubber), was initially 68 and after 2 hours … it was 58!!!
The reason for this is chemical… rubber has very long molecules and this is what gives it its elastic properties. Hydrocarbons break these chemical bonds to make much smaller molecules. Consequently, an earthmover tire exposed to hydrocarbons will exhibit a type of tearing as shown in the picture above, where there has been contamination.
Therefore, it is extremely important to protect your tires during mechanical maintenance! Below is the link to the Michelin guide to the maintenance of aircraft tires. You may ask why airplane tires? The reason is simple. Because there are hydraulic cylinders on the landing gear to move them up and down, it is a well-known problem. Please refer to Section 10.4 of the Guide for more information.
https://www.faasafety.gov/files/gslac/courses/content/269/1100/4222_12Mair_CSM_Interactive.pdf
Have a nice summer!
The LanOTR team