This work highlights the mechanically resonant behaviour of MRI gradient systems when excited with an oscillating gradient, e.g. echo planar readout. Results demonstrate that a beat phenomenon can be observed in the signal phase with a frequency dependent on readout bandwidth and mechanical resonances of the system. Insights of the beat source are derived theoretically and validated experimentally. Data confirms that the beat phenomenon results in increased blurring in phase encoding direction leading to suggestions for system optimization in order to reduce the impact of the beat phenomenon.