Assume that the string bed size is the same and you change from 16x19 to 18x20 not only the level of the tension but also the difference between the tensions changes.
A major issue when you choose tensions for certain racquet is that the length and width of the racquet head stays the same otherwise you introduce stress with a chance of cracks.
And because the change from 16 to 18 is 12 % and from 19 to 20 only 5 % it is better not to change the tensions for mains and crosses with the same amount.
Let us assume that the stringbed is 35 cm long and 26 cm wide:
According to the table the tension for the mains goes down from 65,2 to 56,7 lbs.
The tension for the crosses only goes from 60,9 to 57,4.
As you can see the difference in tensions changes quite a bit, with the 16x19 the mains are strung higher and with the 18x20 the crosses.
In Anyway, the check on the tension is easy:
Measure the length and the width before and after stringing and if they are the same it was the right difference between tensions.
If the length has become bigger the tension in the crosses is too high (which is more dangerous than too low).
Last edited by Technatic; 12-05-2010 at 09:12 PM.