Using Fiber Bragg Grating (FBG) sensors in rolling element bearings is a novel way of monitoring bearings. During prototype testing, differences between sensor readouts were observed, leading to the research question: “What causes the observed differences in the strain distribution from sensor to sensor in a rolling element bearing equipped with FBG sensors?”. Further tests were performed with an interrogator capable of scanning the spectra with a resolution 25 times higher compared to the original measurements, performed with a SmartScan SBI interrogator. These tests showed that in different temperature conditions, sensors may behave differently, resulting in a translation of the strain levels between sensors. Furthermore, it was found that (1) the peak detection method used by the SBI interrogator, (2) the lower resolution of the SBI interrogator and (3) the differences in FWHMs between the sensors and between different load conditions, led to inconsistent strain readings from the sensors.