I would like to upgrade my stock 18" (heavy) wheels to a set of lightweight 19" wheels. After reading this forum, there seems to be quite a bit of discussion whether 19" wheels with their larger diameter, weight distribution and inertia have a negative impact on performance. Apart from this forum, are there other forums or websites I can turn to for more information on this topic?

I never thought that a larger wheel would have a negative impact on the amount of horsepower transferred to the pavement. I'm aware of the benefits of a larger contact patch and a stiffer sidewall on cornering, but it never crossed my mind that a wheel could "rob" horsepower.

 

it can. but there are so many factors with it, it is impossible to have enough info to make a conclusion.

youd have to know atleast the weight of every "peice" of the rim in a grid format, and then determing the distance from center of that peice, get the inertia on it, and then add all the peices back together to get total inertia.

the idea is that on a 19" rim your going to have peices in the outer lip that will be .5" farther from center vs an 18" rim. and in an 18" rim your gonna have peices of sidewall in that .5" to figure. ect ect, it gets complicated.

best place to learn would be a physics book.