Large diameter rims with skinny tyres - the new future?
An example of OEM vs aftermarket are the wheels and tyres I've fitted to my Kizashi. I've gone from OEM 17x7" rims with 215/55R17 tyres to 17x8" rims with 235/50R17 tyres - yet they both weigh the same. There's no way I'd suggest they'd cope with gutters as well as the Suzuki rims, but I'm also not planning on hitting any.
David
Most aftermarket wheels will be lighter...and almost anything is lighter than the Kizashi 18x8s! They're the heaviest wheel I've ever encountered when they have a tire on them. 
But while most aftermarket will be lighter, only few will be as strong as factory or stronger. And those aftermarket wheels start getting quite expensive--up there with the cost of factory wheels or more.
But while most aftermarket will be lighter, only few will be as strong as factory or stronger. And those aftermarket wheels start getting quite expensive--up there with the cost of factory wheels or more.