The 95~97 Ranger speedo is electric but it is driven by a pulse train from a signal generator which is itself gear driven from the transmission or transfer case. The speedometer can be corrected by changing the driven gear in the same way that you would correct a cable driven speedometer.
You will need to find the ratio of the new axle to the current axle and apply it to the current speedo gear count to calculate the new tooth count. If you also change the tire diameter, the ratio of the two diameters would need to be figured in as well. There is a more detailed explanation of how to determine the new speedo gear tooth count on the Tech Library page of The Ranger Station