Bumper-mounted sweeper magnets should be suspended 3- 4” above the ground. At that speed they can sweep effectively at 15 mph. Keep in mind that the sweeping width of these units is less than our tow-behind styles, so it may take longer to sweep a larger area due to the smaller size of the magnet.
For the 3-in-1 Tow Behind, we recommend sweeping at a speed between 3-8 mph (walking speed).