That is true. If you have the same offset but two wheels have a different width, the backspacing will be different as well. For instance, as I pointed our before, my stock 18x7.5 wheels have an offset of 50.8. However, the wheels that I am thinking about buying for winter tires are 18x8. They have an offset of 45, but the backspacing of the two wheels are the same (6.3"). Backspacing is important because it affects how close the tire is to the inside of the wheel well, and that distance on the Pacifica is quite small.
To respectfully disagree with part of this (or at least the way it is described), I believe that 2 wheels of the same offset (even if different widths) will put the center of the wheel in the same location with regard to the chassis. As a single tire width can fit multiple wheel widths (within reason), if the offset is the same and the tire width is the same, the tire will be the same distance from the inside of the wheel well, even if you have 2 different wheel widths (and different backspacings).
Note that it is true that the wheel lip itself will be closer to the wheel well, but it's the center of the wheel that you want to use as your reference point, in my opinion.
- 2017 Pacifica Touring-L Plus - Jazz Blue, Advanced SafetyTec, Uconnect 8.4N, KeySense
- Ordered 5/31/16, Current status: KZL as of 6/28/16, Arrived at dealer 7/6/16, Purchased 7/11/16