Why are two slimmer wheels paired on each side of the axle in buses and container carrying vehicles, instead of a single large broader wheel?
In: Engineering
Two wheels can actually carry more weight than one wheel that is 2.5x the width.
The wider wheel needs to have much stiffer sidewalls and thicker tread to support that weight, otherwise the middle of the tread would buckle and the tire would collapse. There is also more flex in the tire tread that increases wear. By having 4 supporting sidewalls instead of 2, the individual tires do not need to be as strong to support the same weight and flex less. This leads to lighter tires that last longer and give you better fuel economy (all else being equal).
Another reason is redundancy. These tires generally do a lot of work and are put under a lot of stress, so they are more prone to failure. A single wide tire failing would immediately disable your truck and potentially cause a crash, but one of two narrower tires failing generally allows you to keep driving safely enough that you have some time to make it to a safe location.
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