This '69 GTO has 285-19s up front and 345-20s out back, rolling on our ExtReme Frame.
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Alan's Chevelle before he went to 18s for racing- 18's up front and 20's out back. This is with the factory frame and Speedtech control arms.
Guy's '68 Chevelle, 18's up front and 20's out back. This is with the factory frame and Speedtech control arms.
Although some folks do the 18/20 we like to stick with no more than one wheel size stagger if possible to try to keep sidewall heights visually consistent. I think you're on the right path with 19s and 20s for a cruiser. As has been said when we go racing we usually stick to 18s.