Smaller wheel taller tire = better fuel economy?

Has anyone put smaller wheels with taller tires on their Gen 4? On both my Vette and truck, swapping to a smaller wheel with taller tire (and narrower profile too, for example 285 vs 295 rears) improved fuel economy slightly.

Without significantly ruining handling and risking safety, what is the smallest wheel I can run on a Gen 4 Prime that clears the brake calipers, while allowing a narrow (read: skinny) tire with taller profile?

I understand there will be a slight speedometer discrepancy - not an issue as I hardly speed anyways.



Will Toyota's safety systems have issues with the slightly smaller wheel / slightly taller tire and throw faults when in the snow or adverse handling situations?

Hopefully someone here has done this (perhaps with their winter/snow tires) but I'm thinking of the overall effect on MPG if I did this for both All-season/summer and winter tires.

FWIW - I'm getting north of 50MPG highway keeping up with traffic (no hypermiling), so I'm already thrilled with the fuel economy. Just curious as I might get a set of smaller wheels & taller tires for the upcoming winter, as used winter tires are cheap in the summer.