What could happen due to running dual wheels with one tire flat?

Running dual wheels with one tire flat can lead to overheating of the remaining good tire. This occurs because the flat tire cannot support any weight, causing the weight distribution to shift to the tire that is still inflated. The remaining tire experiences increased stress and friction as it carries the load on its own, leading to excessive heat buildup. This overheating can ultimately result in tire failure, such as blowouts or tread separation, as well as causing premature wear.

While it's true that having a flat tire in a dual setup does not mean that it will cause no issues, overheating is a critical concern. It's important to be aware that the flat tire may also lead to additional damage, but the immediate risk posed by the remaining tire must be taken seriously. Consequently, fuel efficiency is unlikely to improve; in fact, it could worsen due to the increased rolling resistance and decreased handling stability that a flat tire introduces to the vehicle.