* Wheel width: Wider wheels will require a different offset than narrower ones to avoid rubbing. An 8-inch-wide wheel will need a different offset than a 10-inch-wide wheel.
* Tire size: The diameter and width of the tire significantly impact how much clearance you'll have. A larger tire will stick out further, requiring a more negative offset.
* Suspension components: Modifications to the suspension (lowering, for example) will change the clearance available. Stock suspension will limit your options compared to a modified suspension.
* Backspacing: This is closely related to offset and is sometimes used interchangeably, though they are distinct measurements. Backspacing is the distance from the mounting surface of the wheel to the innermost part of the wheel.
To find the right offset:
You need to determine the wheel width and tire size you want to run. Then, you'll likely need to:
1. Consult a wheel and tire fitment guide: Several online resources specialize in this. Searching for "1960 Impala wheel and tire fitment" will yield some results. These guides often let you input wheel size and tire size to predict potential clearance issues.
2. Use a wheel offset calculator: Many online calculators allow you to input your vehicle's specifications and your desired wheel/tire combination to estimate the offset needed.
3. Measure (if possible): If you have access to the car and wheels, measuring the available space inside the wheel well is the best way to determine the maximum offset that will fit without rubbing. This often requires test fitting.
Important Note: Using 18" or 20" wheels on a 1960 Impala will almost certainly require modifications. You'll likely need to adjust the suspension, and you may need to roll or flare the fenders to accommodate the larger wheels and tires. Failure to account for this can lead to significant rubbing and damage to your car. Starting with a smaller wheel size and gradually increasing can be a good strategy.
