Also known as “squirt”, cue ball deflection is the natural result of stroking with sidespin, or “english”. When the cue ball is struck by a pool cue, to the left or right of center, it does not go exactly in the direction of the stroke of the pool cue but rather is deflected offline, making it necessary for the player to compensate. The farther the strike is from the center, the more the cue ball is deflected offline. Cue ball deflection also tends to increase somewhat with a faster stroke, for most pool cues from 2% to 3% over the normal playing range of 5mph to 15 mph cue ball speed.
Pool cues vary widely in how much they deflect the cue ball – all pool cues do it, and it may not even be possible to build one that doesn’t. Indeed, the lowest deflecting pool cues have only eliminated about 20% of the deflection caused by the average Pool Cue. The wide variation between Pool Cues is due primarily to the design and construction of the first few inches of the shaft – anything behind this, the joint, the butt, even the overall weight has little effect. While the very low deflecting pool cue shafts are clearly becoming more accepted and popular, opinions still vary. Lower deflecting pool cue shafts require less compensation and many believe this equals greater accuracy, but they also tend to spin the ball more and some feel that means less control. Also there is a period of adjustment to a pool cue shaft that performs very differently and some are not willing or able to take the time to change from what has become so familiar over many years.