Here's mine with 275/60's at the rear, and 235/65's up front. Last month I switched to 255/60 up front.
Adam, 6 J rims are too small, use 7 J or higher. How wide they are? 275 means that the tyre is 275 mm width, but this is not always correct. Sometimes it's a little bit more, or smaller, depends on the manufacturer. But the general idea is that it's the width in mm.
Erik with a "K" did you ever try getting some Buick Rallye's for your Riv ? My brother has a set that he sent out and had them widend. 15 x 8 now.
Jarrod, I still have the original Road Wheels for my Riv, and also two 10 J Road Wheel rims. But here in Europe we don't really like the Road Wheels because they look like a serie of wheels done by Opel in the 70's. Not funny when people ask you all the time: "Are these Opel wheels....? " ou:
