Rolling resistance is only trivial in the lab.
Crr on real roads is far higher than on steel drums and the numbers are far, far from trivial.
With the best tires on my local roads, the best Crr that I have measured is 0.004 with 0.005 more typical and 0.006 on chip seal more like it. At least 30% of my energy goes to the tires. YMMV