The 2005 Chevy Colorado's bumper-mounted towing capacity is
not specified and is generally
not recommended. While the truck might have a receiver hitch option, using a bumper-mounted ball is unsafe and likely to exceed the structural limitations of the bumper itself. The bumper is not designed to handle the stress of towing and could result in damage to the vehicle, loss of control, or even an accident.
Always refer to your owner's manual for the correct towing specifications and recommended equipment for your specific 2005 Chevy Colorado model (there were variations). If you need to tow, using a properly installed receiver hitch and the correct weight distribution setup is crucial for safety.