Hi
I searched google image and found both of them are big trucks.
But I couldn't find the difference.
What is the difference between rig and juggernaut?
According to several dictionaries here OneLook: General dictionary sites , 'rig' is used more in North America, 'juggernaut' in Britain.
Context is always important; labelling is rarely important.
Juggernaut - Definition and More from the Free Merriam-Webster Dictionary
I have only heard the term used in the second sense in AmE. A juggernaut is something that crushes everything in its path, like a great football team.