How do adjust your aim for a fast-speed bank?
The 1/3-more-than-twice bank shot aiming system described in the following articles works well for fast-speed banks: “Fast Speed Banks” (BD, July, 2013) and “HAPS – Part VIII: Bank Shots” (BD, June, 2015). It also works well for banks of any speed if the OB is close to the banking cushion (where it doesn’t have time or distance to develop forward roll). Here’s a diagram from the article illustrating how it works:
The aim always originates 1/3 of a diamond above the standard 2-to-1 mirror system (measured across from the diamonds in the rail groove). It can be referred to as the “(2x + 1/3) to x” or “1/3-more-than-twice system. See the article and the video above for examples of how it is applied. The system is also described and demonstrated in “VEPS GEMS – Part V: Banks and Kicks” (BD, May, 2010). Here’s the diagram from the article that illustrates how the adjustment works. The exact amount of adjustment needed will vary with conditions and the angle of the bank, but 1/3 of a diamond is a good general benchmark reference. The diagram also shows another useful reference for fast-speed banks: the 3-to-1 through-diamond reference. On most tables, shooting through 1 from 3 with very fast speed pockets the ball.
An alternative to the “(2x + 1/3) to x” system described above is a through-diamond system described in the following video: Eckert’s bank shot reference lines. It can be described concisely as the “2x-to-3/4x through-diamond system” as opposed to the “(2x+1/3)-to-x rail-groove system.” Both this system and the system above are described and illustrated in detail in: “Fast Speed Banks” (BD, July, 2013). They actually agree fairly well in the resulting aim, except for very-large-angle banks. Another way to interpret the Eckert system, is the “8/3x to x” or “x to 3/8x” system (by dividing the “2x to 3/4x” numbers by 2). This implies that the aim point on the banking rail (3/8x) is between 25% (1/4) and 50% (1/2) of the distance from the target pocket as the distance on the adjacent rail (x). This provides an easy way to visualize fast-speed banks. When the aim is correct, the aim point on the banking rail is exactly between 50% (1/2) and 25% (1/4) of the distance from the pocket on the opposite rail, which is very easy to visualize without any diamond counting or math.
The following illustration compares the two systems. The systems provide very close to the same lines of aim for small-to-medium-angle banks. At larger bank angles, above the (5+1/3)-to-2.5 line, the “1/3-more than twice” system aim will tend to make the ball bank a little short of target (in which case you can make a small adjustment).
In addition to being able to use the aiming systems above, there are advantages to using fast speed with bank shots. For more info, see: advantages of fast speed.
from Pat Johnson (via e-mail):
You suggest using diamond-to-diamond reference tracks for rolling kick/banks and switch to gutter-to-gutter reference tracks for sliding kick/banks. I noticed you can get about the same adjustment leaving the far end of the reference track pointed at the diamond but moving the near end back a whole diamond, rather than 1/3, along the gutter (yellow lines below)
from John Gaynor (via e-mail):
I found a way to simplify the calculations for the Ralph Eckert system for banking with speed. First, I use 10 as the distance between diamonds. So the 3 to 1 track becomes 30 to 10. Then every point on the target rail that is a multiple of 3 leads to a convenient reference track since the crossing point on the near rail is 8/3 times the point on the target rail. So reference tracks are 8 to 3, 16 to 6, 24 to 9, 32 to 12, 40 to 15, 48 to 18, etc. Calculating between the reference tracks is easy. For example, if you’re between the 24 to 9 track and the 32 to 12 track, the tracks are 26&2/3 to 10 and 29&1/3 to 11, or with slight rounding 27 to 10 and 29 to 11.