What does high offset mean?

What does 'offset rims' mean ?

• i just want to know what the phrase 'off set' rims means.. and if it means a couple things i see this phrase alot when looking at rims on ebay and then i hear people talk ...show more

• Answer:

  Tire rims are sized by the diameter - 13,14,15,16,17,up past 22 inch now, which used to be over the road truck tire diameter. They are also sized by width - 5,6,7,8,9,10 inch. Then offset, or also known as backset, comes in. It is the distance from the back side of the rim to the center surface that is fastened to the hub, ususally with lug nuts and studs. Backset varies because makers use different width axles, or need brake caliper clearance, and need to center the tread width in the middle of the fender opening so the tire won't rub. These days makers are using deep backsets that place the tire much closer to the center of the axle, surrounding the brakes completely. 35 years ago it was the opposite, with narrow axles and small drum brakes, wheels were dished the other way. When matching rims to the fender and axle width, keeping them centered is much more important than running the suspension higher to clear the tire - as is often done on 4WD trucks. A properly centered tire will work with the suspension design rather than create opposing forces that interfere or even defeat certain engineered affects, such as scrub radius or toe-in in turns. Rims with extreme offsets - as viewed by the design engineer - often make handling worse, which will certainly negate any improvement they were supposed to provide beyond looks. Unless you are designing and building your own car, such as a '34 Ford or Cobra replicar, offset is something you only change slightly to accomodate a wider rim, keeping the tread center where it was designed - in the fender well and not rubbing them.