ATV Wheel offset explained:
ATV wheel offset is an expression for a wheel with the same overall width, but the position of the center location makes the ATV wider or narrower. A usual wheel description will look like “12 x 7 (4+3)”. That is a 12in. diameter x 7in. wide wheel. The (4+3) indicates the offset, with 4” being the inside part. Just remember the SMALLER the first number in ( ), the wider the stance will be.
A wider four wheeler or side x side is more stable. A narrower machine increases chances of a rollover, but will operate in tighter quarters and is easier to maneuver through trees.
A different offset wheel is a cheap way to widen or narrow the overall stance. It is a way to add stability (wider) or improve clearance on narrow trails (narrower).
Changing offset will alter the way your ATV behaves, and will affect the load on other parts of the quad. If you try to narrow the machine, you could run into clearance problems with suspension components. Widening the ATV with offset will generally increase steering effort and stress on ball joints, bearings, etc.