In multi-rate wireless systems, the transmission rate is usually selected automatically to maximize throughput. End-toend latency is important when the wireless network is used for time-critical applications, including the control of equipment like smart grids. However, the end-to-end latency characteristic might be degraded because of re-transmission due to multi-rate control. In this study, the influence of the multi-rate control on the end-to-end latency in multi-hop wireless networks is evaluated through certain experiments. Furthermore, some issues of multi-rate control implementation to use for smart grid communication are presented.