Does anybody know the exact weight of volk sf challenge 19" 8.5 front/9.5 rear?

 

I don't know the weights, but you can email Mackin Industries (maker of all Rays brand wheels, including Volk) at productinfo@mackinindustries.com

They will tell you the weights, I have done it before and they usually respond within a day or two. They'll also tell you specific weights for the front and rear sizes.