When you say something has been spinning its wheels, what you mean is that it has remained in the same position. Neither moving forward nor back. In other words, it’s stationary. It’s like pedalling a bicycle while it is on its stand. The wheel keeps turning, but you go nowhere. You remain where you are.
Example: ” You know that the main roads are being widened. But since it’s a government project, you can expect it to spin its wheels for six months at least.”
The expression can be used with people as well. When you say that someone has been spinning his wheels, what you mean is that he has been wasting his time.
Example: ”Some of our employees have been spinning their wheels all morning.” * ”My friend and I had a lot of things planned for the weekend. But we ended up spinning our wheels.”