I think the key word in this question is the one that Marc typed in large bold letters ........ REAR
......... which to me dosen't nessesarily mean the "main" tires.
Perhaps the two aircraft are taildraggers with chines on their "rear" tailwheel.
Are there any taildraggers that use chined tailwheels to help prevent the spray of water, mud, slush, etc, from flying up into the hingeline of the elevator such as a DC-3? Just a thought.
I believe you can see the chine on the one nosegear tire on this Fokker 70.
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