Backup Tracks

eze123

AzB Silver Member
Silver Member
Does anyone have a system for figuring out backup tracks? Say for instance you do a plus 2 shot and come off the third rail with reverse. What's the track off the fourth rail? I know reverse english is tough to call, but there has to be a basic way to figure it, like you can figure the third rail off the second rail contact point with running english. I'm kind of just memorizing all the possible tracks, but there has got to be somebody with some basic system. Just from running the tracks to memorize, the closer to the corner the straighter the track, the farther out on the short rail, the more the angle spreads.
 
The problem with 4th rail tracks is speed and slide. But for approx 4th rail contact point with moderate speed and moderate slide I use as a general rule of thumb the following.

With CB at 3 using plus 2 system.
3rd rail contact point is 7 then 4th is 8-1/2.
3rd rail contact point is 6 then 4th is 9.
3rd rail contact point is 5 then 4th is 10.
 
You're talking the 3-4th rail track, right? I meant the 4th- 5th backup track - those are the tricky ones.
 
eze123 said:
You're talking the 3-4th rail track, right? I meant the 4th- 5th backup track - those are the tricky ones.

They are the tricky because they are so sensitive to how much spin is on the CB at the 4th rail and how much friction there is between the CB and the cushions. I play these shots pretty well and can tell you it requires a fair bit of experience to become comfortable with them.

If you shoot slowly enough that the CB has time to develop follow (normal roll) in the direction of the 4th rail and also doesn't have much reverse spin left on it, you can use angle in = angle out to approximate the 4->5 line.

If you shoot fast speed so you can reverse back up the length of the table, the behavior completely changes. The ball won't have much follow directed towards the 4th cushion, and the reverse left on it will significantly shorten the angle towards the 5th rail.

How much it shortens changes across different tables, though. The higher the friction, the more spin is taken off the CB at the 3rd rail (follow and sidespin), and therefore the less it has on it to shorten the 4->5 line. That's the main reason we don't get nice backups on older/dirtier cloth.

In order to make really good predictions on all kinds of tables, you need a pretty complex model. I'd love to discuss those kinds of details, but this isn't really the place for that. I am working on some instructional material that will address these things.

In the meantime, just take a few representative shots at two reference speeds (slow and fast) to see how a table is playing. It may help to use some fixed long rail points as reference targets. For example, see what it takes to reverse up to the middle of the long rail and to the opposite corner. The lines will not be parallel, and you'll see a pattern to how they fan out. Use your judgement to interpolate intermediate points. Sorry, but that's the best you can do as far as simple answers go!

Robert
 
Robert is right, it is very difficult to identify those rails, therefore you have to train it to calculate the exact points.
get lucky! ;)
 
Robert Raiford said:
I'd love to discuss those kinds of details, but this isn't really the place for that.
Robert

Thanks for the detailed answer, Robert, really appreciate that you posted some detailed technical discussion. Pretty much as I thought, feared, way too many variables to call simply. Oh well, back to the table, I didn't get into this game for simple answers.

But, one thing I disagree on is, this should be the place for that. What else is the forum for? Hell, what if I miss the ball on a backup on the left/long side - is that missing long or short? We can scare the hell out of the newbies all over again! Seriously, though, if you look at the main pool forum, they're discussing squirt, deflection, 'sqwerve' and all kinds of technical stuff all day long, Bob Jewett's throwing in engineering know-how alot. He has a couple videos posted recently with Dr. I forget his name, on how to systemize frozen ball shots, how to tell which ball you hit first if they're frozen, etc. Why don't we have this here?
 
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