You are riding with a universal freestyle wave control bar, set up with "4 direct lines" (low V), meaning that there is no front leader line and no high split point between the power lines (the power lines are connected just after the trim pulley).
You want to shorten or increase the length of the back leader lines.
Here is the trick: the back leader line ends with a knot, to connect the back steering line. The end of the back leader line is spliced into itself, but it is NOT sewed! So you can pull out the end of the leader line and make the knot where you want.
You can leave it as it is once you have changed the position of the knot. If you want the connection to look clean, you can splice the back leader line into itself, as we do it on this video. If you don't have a splice needle, then you can use a small wire and bent it to grab the end of the leader line.
If you splice the end of the back leader line into itself, then the total length of the leader line will be reduced (about 1/2 inch).
Here is another video in case you don't have a splice needle:
If you are using a universal freestyle wave bar with a higher split point, and you want to change the length of the back leader lines, then the easiest way is to convert the bar to a low V (low split point, no front leader line). Then you need :
- a new safety line (shorter)
- a connector for the front power lines
