Wheel offset calculator.
Will it poke? Will it rub?
Enter your wheel and the new one. See exactly how much further out it sits, how much closer to the suspension, and the backspacing of each.
- Outer edge (fender side)
- +1.22" further out
- Inner edge (suspension side)
- +0.28" closer to the suspension
- Track width
- +2.44" across the axle
- Backspacing
- 5.43" → 5.71"
Moves both ways: wider toward the fender and toward the suspension. Worth a test fit, or a trim check with the retailer.
Offset, width and where the wheel ends up
Two numbers decide where a wheel sits: its width and its offset. Width spreads the wheel equally to both sides of its center line; offset slides the whole wheel in or out. A wider wheel with a lower offset is the classic aggressive truck look, and it is exactly the combination that can rub the fender. The drawing above shows the change to scale.
Questions
What is wheel offset?
Offset is the distance in millimeters from the wheel's center line to the face that bolts to the hub. A positive offset pulls the wheel in toward the suspension, a negative offset pushes it out toward the fender. It's stamped on the wheel as ET, for example ET30 or +30.
What is backspacing?
Backspacing is the distance in inches from the mounting face to the inner edge of the wheel. More backspacing puts the wheel closer to the suspension. It follows from the width and the offset, and the calculator works it out for both wheels.
How much poke is too much?
On most trucks and SUVs, up to about half an inch past the stock wheel is usually fine. Beyond that, check the fender line: the tire can rub at full steering lock or when the suspension compresses. Lifted trucks and wider fender flares allow more.
Why does a wider wheel change the fit on both sides?
Width grows from the center line outward in both directions. With the same offset, a wheel one inch wider sits half an inch further out and half an inch further in. Lowering the offset moves all of it outward.
Do I need spacers?
Only when a wheel sits too far in to clear the brakes or suspension, or for a wider stance. A spacer changes the effective offset by its thickness. Use hub-centric spacers from a known brand, and re-torque the lug nuts after the first drive.