We propose an adaptive data rate control method for mobile terminals in 1xEV-DO high data rate wireless networks. The method dynamically adjusts and maintains a signal-to-interference-plus-noise ratio (SINR) threshold and an "effective" data transmission rate for each discrete data rate option. After channel SINR measurement, the mobile terminal uses the SINR thresholds and effective transmission rates for the selection of the data rate option with highest possible throughput. At the same time, packet error rate is maintained at a target value by dynamically adjusting the thresholds according to the pattern of received frame errors. The algorithm allows the mobile terminal to adapt to changing channel conditions and it is very practical since it works based on a closed loop rate control mechanism. Simulations, for a wide range of channel conditions, show that the method maintains a target packet error rate and it results in higher throughput compared to other approaches where a fixed margin is added to AWGN thresholds. We also develop upper bounds on the achievable throughput for high mobile speeds and show that the results of the proposed method is very close to maximum achievable data rate.