Offset is the distance, in millimeters, from a wheel’s mounting surface to its true centerline, and it determines whether the wheel tucks inside the fender or pushes outward toward it. It’s stamped on the wheel as “ET” followed by a number (from the German Einpresstiefe).
The three types
Positive offset means the mounting face sits toward the street (outer) side of the centerline, pulling the wheel inboard — the norm on front-wheel-drive cars. Negative offset puts the mounting face behind the centerline, pushing the wheel outward for a wider, more aggressive stance — common on trucks and off-road builds. Zero offset is dead center.
Why it matters for fitment
Changing offset moves the wheel in or out, which affects clearance to the suspension and fenders, the steering’s scrub radius and feel, and how loads are carried by the wheel bearings. Too much positive offset (or a wider wheel) can rub the strut or inner fender; too much negative offset pushes the tire past the fender, invites rubbing at full lock or over bumps, and adds leverage that stresses bearings. For everyday replacements, stay close to the factory offset unless you’ve deliberately planned a fitment change with wheel width and tire size in mind.
Frequently asked questions
What does ET mean? The wheel’s offset in millimeters.
Positive or negative for trucks? Trucks often run lower or negative offset for a wider stance; match your build and check clearance.
What happens if offset is wrong? Rubbing, altered steering feel, and faster bearing wear.