Back when Bob Summerville was still with us and was running BTM (and doing most if not all of the ball reviews) there was some confusion about what BTM meant by hook and by backend.
Here's how he described their use of the terms. He said hook meant total boards covered. If the ball was started out on the 20 board and went out to the 5 board at it's furthest out and came back to the pocket at the 17 board (give or take a half board or so), then the ball went out 15 boards and returned 12 boards for a total hook of 27 boards.
For backend, he said that was gauged by how many boards the ball covered on it's way back to the pocket from the breakpoint. This is where the confusion was, and to a great extent still is. If the breakpoint was reached at the 10 board at 35 feet, or the the breakpoint was reached at the 10 board at 45 feet, those two balls would be ranked the same for backend, since they both covered the same number of boards from breakpoint to pocket. Obviously, the ball that reached the breakpoint at 45 feet turned much sharper to reach the pocket than the ball that reached the breakpoint at 35 feet; but the backend rating would be the same. The only numerical statistic that could be used to distinguish the obvious and important difference was "core torque." The core torque statistic is a vague general measure of a ball's "flippiness." While the two balls mentioned above would rank the same for backend, the one that reached the breakpoint at 45 feet would most likely have a higher number on the core torque scale. This system is an admittedly imperfect way to quantify ball reaction for purposes of a review.
The wide differences of opinion that we see around this site about different balls expose the imperfection of this system, or any system that anyone has come up with yet. Lots of reading, watching, and personal experimentation still results in most of us buying ineffective equipment on a fairly regular basis. This explains the huge amount of activity in the "For Sale or Trade" forum. That, and the irresistible urge many seem to have to try out everything that everybody makes.
Shiv
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Listening to the monotonous staccato of rain on my desk top