Wheel And Tire Fitment Rear Wheels
Taller rear tires put down a larger footprint, which improves traction but also reduces the effective rear-gear ratio. For example, if you've got 3.50 axle gears and 26-inch-tall tires, the engine will spin 3,166 rpm at 70 mph assuming no overdrive or slippage. Changing to 28-inch tires would reduce the rpm to 2,940, which is about the same effect as if you'd kept your 26-inch tires and swapped to 3.25 axle gears.