Notice that the phone was mounted at the very front of the car. Ours is a 3 wheeled car. 2 powered wheels at the back and one ball castor at the front. Mounting the Nexus at the front changed the weight distribution on the wheels. The castor was taking a lot of load and the rear wheels are not taking enough load. Because the rear wheels was not taking enough load, we were not getting enough traction on the rear wheel. Meaning the rear power wheels were slipping a lot of the time. Since we could not easily shift the camera to the rear we added some more weight at the rear hoping the traction will be enough. This worked. Ideally we should be figuring out a way to distribute weight better.