Rolling resistance isn't the whole story, you live or die on the contact patch.. The [three or] four contact patches are complex. Weight vs area. Theoretical friction is independent of the weight, but any drag racer knows better. Wide tires corner better, tall tires have a longer contact patch.
hecomodder.com/forum/showthread.php/bridgestone-announces-large-diameter-narrow-tires
BMW i3 tires at ~26.5" diameter will take a 19" wheel. Examples would be 1947 MG-TC and 1928-31 Model A Ford. How many lugs on what PCI circle do you have?
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Single-wheel drive tricycles
suck are suboptimal. Here're the Blackjack kit cars, the 2CV-based Avion on the left and VW-based Zero on the right. Each with Moto-Guzz V-twins.
I like the FUV's ride height. Something like the T-Rex (or one of those Blackjacks) is so low it needs a orange triangle whip flag for visibility. The CG is very low, the Roadster's even lower.
edit:
The was a company in the UK that replicated a number of old microcar bodies. They're apparently gone and I don't recall the name. A search here might turn it up (to no point).
