The reason of the failure of the robot to rotate in this video was a problem of the plate structure. As we put the weight on the robot, the bottom plate hit the floor and could not make the desired turn when it rotated. So, now, we are making the plate stronger and making it easier to assemble.
If I answer your question, the maximum load will depend on the type of hardware you have assembled. For example, the maximum load may vary depending on the torque of the motor used, the method of coupling the plates, and the support used. As you know, the shape of Turtlebot 3 is very diverse. Turtlebot 3 in the video is just one example. Attach a picture of the examples we are currently testing. Please enjoy the following videos and news.