The purpose of a driver is directional distance; you can't hit a driver shot too far, only too short or off-line. Distance is a combination of swing speed and loft. More precisely, loft is dependent upon the flex of the club shaft, which is determined by swing speed. If a club shaft is too stiff for your swing speed, the loft trajectory is flat and the distance is short. If the shaft flexes too much because you swing too hard, controlling the direction of the shot is difficult. Where your shot goes is as important as distance.
Know Your Swing
Golf swing radar gun (optional)
Measure your golf swing speed with a swing radar gun. You can also measure swing speed by hitting 10 golf balls with a driver, disregarding the longest and shortest shots, measuring the distance of the remaining eight balls, adding the distances together and dividing by eight. Divide the sum by 2.3 and you have your swing speed in miles per hour.
Match your swing speed to the correlating type on a flex shaft chart. There are two speed ranges specific to women for flex shafts: Lady's Light and Lady's. The Light is for lady's who swing slower than 60 mph. The Lady's is for women who swing with a speed between 60 and 70 mph. The Senior's flex shaft is for a swing between 70 and 80 mph and the Regular is for swings of 80 to 90 mph. If you are a woman with an extremely fast swing speed, there are also three stiffer shafts.
Test three drivers. Test one with a shaft designed for the speed range you fall within, one with a shaft below your speed range and one with a shaft above your speed range. Hit 10 balls with each and take account of your distance and accuracy. Select the club that gives you the best combination of the two. If you have difficultly deciding which club that is, discard the least accurate or the shortest club shaft, and retest your shot with the remaining two.