What is wheel offset and PCD?
Want to know what wheel offset and what PCD means? Well you’re in the right place.
WHAT IS WHEEL OFFSET?
Offset is the distance between the mounting surface of the back of the wheel and the wheels true centre line and it’s important for two reasons. First, if the offset of your aftermarket wheels varies too much from the manufactures standard specification it can compromise steering response and directional stability as well as putting excess load on components like wheel bearings. Secondly the wrong offset can make the wheels or tyres may foul suspension, brake components or the inner arches.
Offset is expressed as an ET number, (ie is ET38) and the ‘ET’ is a shortened version of the German word ‘Einpresstiefe’ which means ‘insertion depth.’ The number is the distance in millimetres between the centre line and the mounting surface.
It sounds confusing but the important thing to remember is wheels with a positive offset will have the mounting surface towards the front of the rim and those with a negative offset will have the mounting surface towards the back often giving the wheel more ‘dishey’ appearance at the front. For most aftermarket wheels the offset helps compromise between increased wheel width and the space available under the standard arches.