There’s nothing saying a properly engineered foam wouldn’t behave exactly as well.
I posit to you that a pneumatic tire is exactly the “properly engineered foam” you describe: a closed, single cell foam with a substantial enclosed volume, leveraging the high tensile strength and toughness of its steel or Kevlar threads for the cell walls.
I’m also no physicist, but minimalist engineering would tend toward reduction of mass and surface area. Multi cellular foams need to expend material for the inter-cell walls. A single cell of equal volume and similar material has only its single, outer cell wall. Plus, just because a cell encloses a smaller volume doesn’t make it any stronger than a larger cell, so no advantage is gained nor lost by having a single cell.
Can a multicell foam be used as a tire? Of course we can press it into that use. Humanity has made concrete float, after all. But will foam be superior in cost, strength efficiency, weight, rotational intertia, roadside repairability, or in-field tunability by changing the air pressure? No. Instead, as the renowned cyclist described in the earlier link, an airless tire would have to compete on its strength of damage resistance:
They might make sense is if you commute a short distance to catch a train, and a flat tire would mean missing the train and being very late to work.
This type of scenario is no different for an acoustic or electric bike, and so there’s no apparent reason that ebikes should necessarily prefer airless tires. The pneumatic tire’s speed and range benefit still make it the preferred wheel technology for most automobile, bicycles, and airplanes. In space, that’s a different question altogether.
I posit to you that a pneumatic tire is exactly the “properly engineered foam” you describe: a closed, single cell foam with a substantial enclosed volume, leveraging the high tensile strength and toughness of its steel or Kevlar threads for the cell walls.
I’m also no physicist, but minimalist engineering would tend toward reduction of mass and surface area. Multi cellular foams need to expend material for the inter-cell walls. A single cell of equal volume and similar material has only its single, outer cell wall. Plus, just because a cell encloses a smaller volume doesn’t make it any stronger than a larger cell, so no advantage is gained nor lost by having a single cell.
Can a multicell foam be used as a tire? Of course we can press it into that use. Humanity has made concrete float, after all. But will foam be superior in cost, strength efficiency, weight, rotational intertia, roadside repairability, or in-field tunability by changing the air pressure? No. Instead, as the renowned cyclist described in the earlier link, an airless tire would have to compete on its strength of damage resistance:
This type of scenario is no different for an acoustic or electric bike, and so there’s no apparent reason that ebikes should necessarily prefer airless tires. The pneumatic tire’s speed and range benefit still make it the preferred wheel technology for most automobile, bicycles, and airplanes. In space, that’s a different question altogether.