Shaped String Considerations
Monofilament string can be easily produced in almost any shape. Round, square, triangular, hexagonal, octagonal etc. So, on the surface that seems like a good thing. Who wouldn’t want the sharp edges digging into the ball creating even more spin!
But, there may be a side to the shape that needs considering and that is tension as it is applied to the string vs tension as it is in the racquet. Those can be two very different things!
When the main strings (the long ones usually) are installed they are free to move and will normally be only slightly “twisted”. This is more obvious with square and triangular strings.
This image shows one of the lower cross strings and the “twist” is obvious. So what?
So the tension on these strings will be considerably lower than expected.
Why? The machine tension head is set to pull each string to the desired setting, say 50 pounds. When the machine “feels” 50 pounds the tension head stops. The cross string will twist, just like a screw, as it passes over and under the main string. A twisted string will not pull through the adjacent main strings easily so the tension will, in this area, be less than desired.
This variation in “tension” can affect the way a ball comes off the racquet.
We use string spreading devices for every racquet and every type and shape of string. The “spreaders” raise and lower the main strings so there is no friction (twisting) between the cross string and the main string.
Not all racquet technicians use this type of device, so, the twisting can be mitigated by weaving the appropriate cross stings over and under the main string one at a time making sure they are not twisted and then apply the machine tension. This will result in a more consistent result.
If your racquet has cross strings that look like the image be sure to mention it to the stringer so it can be remedied.