Do smooth hubcaps (for example, a "Baby Moon") help with FE? Has anyone tried it? If so, how much did it help?
This seems to me like it might be one of the easiest aerodynamic mods to make (since you just buy the hubcaps, and put them on). And it is pretty cheap to buy a set of hubcaps. But does this help? My thinking says it could go either way:
1) It might hurt FE, because the wheel covers will weigh something, and this will (slightly) raise the weight the wheel has to turn. OTOH this added weight isn't that high (especially compared to the weight of the tire and wheel itself).
2) OTOH it might help FE, because smooth hubcaps should make the wheels more aerodynamic, by covering over the places the air can get trapped in.
Either way, this mod should be reasonably cheap and easy to do (just buy a set of hubcaps, and put them on). And unlike some aerodynamic mods, this one isn't likely to draw a lot of attention to itself (as many people snap hubcaps on their wheels). And it should even cover up the rust on the wheels themselves.
But has anyone tried this (and if so, how well did it work)?
DracoFelis 
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