What is the difference between Wheels and Castors?

Wheels and castors are both types of circular mechanical devices that are used to support and move objects. However, there are some key differences between them:

1. Design: Wheels are typically better on surfaces that are soft or uneven such as outdoor settings such as lawns, gravel, uneven surfaces.  Castors on the other hand are designed for smooth flat surfaces like concrete or decks. 
2. Castors are designed to swivel and pivot in any direction, wheels by comparion are usuallt set in a fixed direction. This makes them castors more versatile for short distance movemebt, but they may not roll as smoothly as wheels on uneven surfaces.  Wheels are generally are better on soft and uneven surfaces due to their larger diameters.
3. Purpose: Wheels are typically used to support and move heavy loads, such as vehicles, carts, and other transportation devices. Castors, on the other hand, are smaller and are used to support and move lighter loads, such as furniture and equipment.
4. Attachment: Wheels are typically attached directly to the object they are supporting, whereas castors are mounted on a separate frame or plate that is attached to the object. This allows castors to swivel and move more easily, as they are not directly attached to the object they are supporting.
5. Size: Wheels are generally larger and thicker than castors, as they are designed to support heavier loads. Castors are smaller and thinner, as they are designed for lighter loads.

6. Load capacity: Wheels are able to support much heavier loads than castors.

Overall, the main difference between wheels and castors is their size and intended purpose. Wheels are used to support and move heavy loads, while castors are used to support and move lighter loads, and are more versatile in terms of movement.