TireFitCalc

Guide

Wheel Offset & Backspacing Explained

ET, offset, backspacing — the difference between a perfect fitment and rubbing.

Key takeaways

  • Offset (ET) is the distance in millimeters between the wheel's mounting surface and its centerline.
  • Stock European cars typically run ET35–ET45.
  • Always pair offset changes with the right tire width to avoid suspension or fender contact.

Jump to a related tool

Main explanation

Offset (ET) is the distance in millimeters between the wheel's mounting surface and its centerline. A higher ET tucks the wheel inward; a lower ET pushes it outward.

Stock European cars typically run ET35–ET45. Aggressive fitments can drop to ET20 or lower, but you may need fender rolling.

Always pair offset changes with the right tire width to avoid suspension or fender contact.

Frequently asked questions