All Expeditions can handle 32 inch true-to-size tires from what I've seen on this forum. Going beyond that will require modifications, and will change the geometry of your machine. Trust me, I know what I'm talking about. I went with a larger tire than recommended on one of my older rigs and paid the price by making it top-heavy.
If you go beyond 32 inch, you need to modify your machine. When I say modify, do all you can to make it more stable, otherwise, you too can join the severed shoulder ACL club when you flip it over. (Yes, that's my shoulder Sept 2021)
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