The universal caster is the so-called movable caster, and its structure allows 360-degree rotation horizontally.There are many kinds of materials for making universal wheels, the most common materials are: nylon, polyurethane, rubber, cast iron and other materials.The most common thing in our daily life is the universal wheel of the suitcase. But sometimes you will find that the universal wheel of your suitcase is not very flexible, so what should you do?1. Detect the visible wear degree of the tire tread. The "smoothing point" on the tire tread can indicate the accumulation of foreign matter, such as thread, iron wire and other debris may be wrapped around the wheel, then you need to remove the bolts and nuts on the wheel and clean up the debris. Check whether the wheel bearing is damaged. If the parts are not damaged, they can be reassembled and used again. If the wheel is often entangled by debris, it is recommended to install an anti-winding cover to avoid it.2. The loose casters of the universal casters or the stuck wheels can also cause "smoothing points". Proper maintenance checks, especially checking the tightness of the bolts, the amount of lubricating oil, and the replacement of damaged casters can enhance the rolling performance and rotational flexibility of the swivel wheels of the luggage.3. Severely damaged or loose rubber tires may lead to unstable rolling, air leakage, abnormal load, and damage to the bottom plate, etc. Prompt replacement of damaged tires and bearings reduces problems caused by damaged casters.4. After checking and repairing the wheel, make sure that the bolts and nuts are tightened, and use lock washers or lock nuts on all bolts as much as possible. If the bolts are loose, tighten them immediately. If the wheel installed in the bracket is loose, the wheel will be damaged or unable to turn.5. If you find that the universal wheel is very stuck, it is caused by the damage of the steel ball of the steering gear or the entry of contaminants. This basically cannot be disassembled, and generally cannot be repaired, only the casters can be replaced.The luggage with universal wheels is actually composed of two universal wheels and two directional wheels at the bottom. When dragging with a tie rod, the directional wheel plays a role, and when standing and pushing, the universal wheel plays a very important role, and even children can push the heavy universal wheel luggage at will. It's also very labor-saving, so if you need to buy a suitcase, we recommend buying a suitcase with swivel wheels.