Before you attempt to modify your portable kitchen island, verify that overhang causes the island to tip. Empty the cabinets at the base of the island, clear its surface and remove items that hang from hooks on the island, such as towels and cookware. A number of small items all on one side of the island can offset its balance, and reorganizing the contents may solve the problem. If the empty island still tips easily, it is clear and ready for modification.
Measuring your portable kitchen island's overhang will help you determine whether or not it is within standard dimensions. Depending on the island's height and the types of seats used, an overhang in the 12- to 15-inch range is typical. Some islands, particularly built-in islands, feature 18-inch overhangs to give diners more leg room. An 18-inch overhang on a portable island, however, may be simply too much weight positioned away from the island's center of gravity.
One of the most straightforward solutions for a portable kitchen island that tips over due to its overhang is to reduce the amount of overhang. The task's difficulty varies based on the island's construction and materials. Cutting a granite or composite counter top requires special tools, while a wooden counter top with a vinyl, veneer or ceramic tile surface is easier to disassemble, cut to size and reinstall. A 12-inch overhang that is consistent on all sides of the island should be sufficiently light and balanced.
Instead of reducing the size of the island's overhang, you could alter the island's structure to handle the existing overhand. Moving the island's wheels or casters closer to the corners of the island's base will distribute the item's weight and give it a lower center of gravity. Extending its cupboards and spreading the wheels will add storage space and reduce the overhang indirectly by filling in the space below the overhang.