What offset actually is
Offset — the ET number stamped inside every wheel — is the distance in millimetres between the wheel's hub mounting face and its centreline. Positive offset (e.g. ET45) means the mounting face sits toward the street side, tucking the wheel into the arch. Low or negative offset (ET0, ET−25) pushes the wheel outward — the "poke" you see on off-road builds.
Related term worth knowing: backspacing — the distance from the mounting face to the wheel's inner lip, common in American off-road catalogs. Same concept, measured from the other direction.
What changing offset does
| Change | Visual effect | Mechanical effect |
|---|---|---|
| Higher ET (more positive) | Wheel tucks inward | Risk of rubbing inner suspension; narrower track |
| Lower ET (toward 0/negative) | Wheel pushes out — wider stance | Wider track, more bearing load, possible arch rub, heavier steering |
| Matching OE ET | Factory stance | Factory geometry preserved — the safe default |
Offset also shifts scrub radius — the geometry your steering was engineered around. Small moves (±10 mm) are generally invisible in daily driving; big moves change steering feel and wear. That's why every fitment we sell is offset-verified against your exact car, not just the bolt pattern.
Choosing offset when upsizing
The working rule: when going wider, the extra width should be split across both sides of the wheel, which usually means slightly lower ET than factory to keep the inner edge clear of suspension. Example: moving from an 8" ET45 factory wheel to a 9" aftermarket wheel typically lands around ET35–40 for the same inner clearance.
Fine-tuning after the fact is what hub-centric spacers are for — a 15 mm spacer turns ET45 into an effective ET30. Off-road builds chasing stance go the other way deliberately; if that's you, read our beadlock guide too.
Or skip the maths entirely — our vehicle search only shows wheels whose diameter, width and offset are verified for your car.
Quick answers
What does ET mean on a wheel?
ET is the offset in millimetres — the distance from the wheel's mounting face to its centreline. ET35 means the mounting face sits 35 mm outboard of centre. Higher ET tucks the wheel in; lower or negative ET pushes it out.
Can the wrong offset damage my car?
Yes — too little offset stresses wheel bearings and can rub the arches; too much can hit suspension components. Staying within a sensible window of your factory ET protects both.
Do spacers change effective offset?
Exactly — a 15 mm spacer makes an ET45 wheel behave like ET30. Hub-centric, properly rated spacers are the safe way to fine-tune stance; see our accessories range.
