[Gliding_Serpent]

An extreme example is the GT350R vs non-R wheels.

Do the Shelby GT350R?s Carbon-Fiber Wheels Help Performance? ? Feature ? Car and Driver | Car and Driver Blog

This is so horribly unscientific. There is no data here supporting lighter wheels being faster. The cup2's have more grip... I know they did rolling starts, but you don't need wheel-spin to see grip differences. Think cornering. One can corner much faster than the other without tire squeal to to compound advantages. And then they go to discuss all the upgrades the R has in suspension (presumably resulting in more grip as it is stiffer). It is not apples to apples and there are too many variables changing.

They should have matched rubber, or swapped wheels/tires between each car and compared runs with each wheel. That would at least help eliminate some of the car differences from the equation.

Not saying lighter wheels do not help (they do), but the article sadly proves nothing.