4" vs. 6" + 8" Diameter Wheels

[sgreco]

Originally Posted by Ether

Yes, useful exercise for students.

The numbers above can't be used, of course, to answer the original engineering question, to wit: all other things being equal, how much acceleration advantage does a 4" wheel vehicle have over a 6" wheel vehicle (where both the 4" and 6" wheels have been reasonably individually optimized for the vehicle).

Does anybody have CAD models (from this or past years) of 4" vs 6" drive train options which included enough detail to calc the mass and moment of the wheels?

We don't need a CAD model to do a rough estimate. We could assume 140 pounds (close to full size robot + battery + bumpers). We could assume a somewhat reasonable gear ratio (4 CIMS geared down 18:1 with 6 inch wheels and 12:1 with 4 inch wheels). Theoretically these are geared to move at the same speed, the problem is we don't have estimates on the exact weight savings with a smaller gear ratio and smaller wheels (someone else might be able to help estimate the weight savings).