I have 1 inch wheel spacers on front and rear. When I get to 80-85mph the seats shake. I had my tires road forced balanced twice. Tire size 32 10.5 R17
I have 3 tunes
Octane 87
Octane 91
Octane 93
I tow a mower everyday so does that mean I run the octane 87?
I also noticed running the octane 87 it shifts a little harder. Is that normal?