Our what is the idle rpm for a vibrating grizzly screen or shaker. Topsoil Screener SLG 108VF - IDM. ... Jan 30, 2007· Vibrates at idle..800 rpm + or -, 15-1600, 2250-2450. It's very pronounced with a trailer, mostly at cruising speeds, 15-1600 @62 MPH. It's a harmonic resonance. If I take it out of top gear and get the RPM up, it goes away.