According to the United States Racquet Stringer’s Association, it is acceptable to pull tension 2 – 3 ahead on the main strings. Stringer’s who follow this practice regularly are able to achieve CRT and MRT status. While considered acceptable industry practice, we are not convinced this technique creates the most consistent stringbed possible. As a result of this belief we have altered our technique to one where we pull tension on each alternate main as a matter of routine.
With the use of a Stringmeter and ERT we have been testing this premise in our shop. While tensioning mains 2 or 3 ahead before alternating sides we are able to achieve consistent ERT (stringbed stiffness) readings. However, we have discovered that when measuring individual strings with a Stringmeter that an interesting phenomena exists. It seems that parrallel strings (i.e. main #4 on each half of frame) offer identical readings when strings are tensioned using a strict alternating method of tensioning. (Alternating tension on each side going no more than 1 ahead). However, when using a method of pulling tension 2 or 3 ahead the reading on parrallel strings can vary by 3 – 10 pounds! The amount of variance is not consistent, or at least with our limited testing we can not identify a pattern or formula. What we can identify is that a technique consisting of tensioning 2 -3 main strings before alternating sides creates a level of variance that can be measured with a Stringmeter, but does not register on an ERT.
Of course this raises some key questions for stringers. Can players perceive this variance or is it insignificant if the overall stringbed stiffness is consistent? What causes this variance?
Our response to the later, is that this variance could very likely be caused by frame flex. In spite of secure 6 point mounting systems of today’s advanced machines, the racquet will experience some degree of flex while being strung in any machine (with the possible exception of True Tension machines). We hypothesize that the uneven tensioning creates a flex situation that leads to results with undesired variances.
At this point in time we are unclear as to how or if this variance can alter the play of the racquet. What we have been able to do is to identify it as an area that needs additional study. We will need to call on the industry physicists, engineers and the USRSA to explore this further and determine if it is a factor that is or is not important for generating a stringbed that produces ultimate playability.
Until more information is generated, our customers can be assured that all racquets strung by us will be done focusing on the most consistent outcome, even if it extends the time to complete the stringjob by a few minutes.