Is the recommended tension range LO or CP?

[KendraB]

Racquets have a recommended range for the tension at which they should be strung. As many here will know, there are two kinds of machines - manual crank lockout and constant pull. With many strings, especially nylon, constant pull machines will string 5 pounds tighter than lockout machines (because they get more stretch out of the string before it is clamped). Is the recommended tension for a racquet LO or CP? I don't know, but from my experience I would suspect that it is LO. What do you think?

[PBODY 66]

This came up in a USRSA article a few years ago, and as I recall there was no industry wide standard. I tend to take the reference machine to be constant pull, but that is because I current use one.
If it is a first time frame err on the side of being to low.

[KendraB]

Hi Pbody66. Thanks for the info. Isn't it crazy that there is no industry standard? Once I had to redo a VS gut job, losing money on the job, because it was too tight.

[STRINGA]

Hi Kendra,

It think that this matter is a of fundamental matter.
I think that “stringing on stiffness: should be the way because you string for a certain result in the racquet. A player feels the stiffness not the tension that is used on the machine to get that result.
And because there is a lot of difference in the results of stringers not only because of CP or not, it would be good to go from the result.
This actually means that you choose a stiffness that you want and calculate the stringing tensions to use on the machine.

I use the Stringway Tension Adivisor for a long time and with this tool you do that.
You enter the inside length and width of the racquet head and the number of mains and crosses and the system and you choose the stiffness that you want and the system calculates the tensions.

http://img23.imageshack.us/img23/3153/tensionadvisorkl.jpg


I have this system also in tables which I can send to you if I have you address.

BTW, the difference in result between CP and LO are much bigger than 5 lbs and depend strongly on the type of string. I have a document that shows that the difference can be up to 17 lbs.

[DarkHors]

Stringa, could you send me the file you have for the stiffness of the stringbed? My email is ryan.carlson2 at gmail dot com.

[KendraB]

Hi Stringa,

One of my machines is a Stringway ML 100, and they sent me the Tension Advisor when I bought the machine from Alpha last November. I would love to have the Stringway stringbed stiffness measuring device, but I can't afford it right now. As to the problem of there being no industry standard regarding recommended tension, i.e., whether it is lockout or constant pull, yes, that is a problem. People give you a racquet and say, "Put in the middle of the range." Great. Is the range figured in terms of LO or CP?

[gotwheels]

STRINGA, A question for the Stringway String Tension Advisor System: I was adjusting the stringbed of a Head MicroGel Prestige Pro MP (98, 16x19) for a Junior player that did not recall his string tension for his requested string (Prince SG with Duraflex 16 White). I knew the player played with relative low reference tensions form some work I did ~18 months ago using a multifilament/SG hybrid. With the stringbed dimensions, I targeted at DT of 31 (using interpolation of the chart with the stringbed dimensions). The reference tension that I used was constant pull 48 lb. mains / 52 lb. crosses (using a Jay Cee style, fixed clamps, slight SG prestretch). My results using an ERT 300 was a DT of 36 kp/cm and 34 kp/cm at 24 hours after stringing, higher than I had anticipated. The completed stringbed width did measure 1/16" wider and no change in length.

Based on your knowledge/experience (which I have much respect for), would you comment on my variation? I assume the chart/advisor values are based on a string standard (?) and the values vary with different types of string? Is interpolation of the chart values (assume linearity) acceptable? Are there chart data for other DTs beyond 28,31, 34, 37, and 40?

Thanks in advance for your thoughts.


KendraB, The following is some old USRSA data (I do not have a date)

"Back in July 98, the USRSA published an article covering the question as to whether recommended tension ranges were for lockout or constant pull machines and what adjustments stringers could make if their machine was not the "targeted" type. Here is the list from that article:

Company---------Machine Type------ Recommendation
_________________________________________________

Dunlop---------- Lockout-------------Reduce tension 10% on CP machines
Head ----------- Constant Pull-------Lockout users may increase tension 5%
Prince-------- Constant Pull-------- Lockout users may increase tension 5%
Pro Kennex----- Lockout --------- Reduce tension 10% on CP machines
Spalding ----- Lockout --------- Reduce tension 10% on CP machines
Volkl----------- Constant Pull ---- Lockout user may increase tension 10%
Wilson ---------Constant Pull----- Lockout user may increase tension 5% "

I do not know the significance of this information, as I believe that one is OK with either constant pull of lockout within the manufacturer suggested tension range. I would like to see more of our posted information qualified with reference tension, note CP or LO machine (I hope calibrated), and measured DT (and time of measure such as immediately after stringing, at 24 hours, etc.). This helps me in data interpretation. As stringers, we add enough variation to skew results!

Good stringing to all.

[STRINGA]

Hi kendraB

The first thing that you seem to need is the SW routemap as shown below:
With this route map you decide on the stiffness that you need for different types of players ladies and men. There is one map for a man and one for the woman.

http://img6.imageshack.us/img6/9120/routemapmankl.jpg

It works as follows:
Answer the questions in the map and you will get to an advise in stringing stiffness and in string.
Stringway does not offer strings anymore because they concentrate on the manufacturing of stringing machines.
When they sold strings they divided their strings in 4 categories based on the qualities of the strings in the first place on the elongation characters.

So the advise consists of a stiffness in combination with a string.

Because the stiffness is of the first importance you can use this and select a string out of your own stock.

Because you have the SW ML100 you can use the tension Advisor values. When you would measure the stiffness you will notice that the stiffness will be 1 to 3 points higher depending on your stringing qualities.
This is ok because the string will loose tension during play so it will get to the chosen value.

Stringa
I do not think that the difference in tension between a LO and CP depends on the racquet type, I think that it depends on the type of string that you use.
If you use a string with bad elongation qualities you will loose more tension during stringing than a good quality string.

The SW stringing seminar describes the elongation of strings.

For those who are interested just send me your email address and I will send the maps and the seminar.

Stringa

[STRINGA]

STRINGA, A question for the Stringway String Tension Advisor System: I was adjusting the stringbed of a Head MicroGel Prestige Pro MP (98, 16x19) for a Junior player that did not recall his string tension for his requested string (Prince SG with Duraflex 16 White). I knew the player played with relative low reference tensions form some work I did ~18 months ago using a multifilament/SG hybrid. With the stringbed dimensions, I targeted at DT of 31 (using interpolation of the chart with the stringbed dimensions). The reference tension that I used was constant pull 48 lb. mains / 52 lb. crosses (using a Jay Cee style, fixed clamps, slight SG prestretch). My results using an ERT 300 was a DT of 36 kp/cm and 34 kp/cm at 24 hours after stringing, higher than I had anticipated. The completed stringbed width did measure 1/16" wider and no change in length.

Based on your knowledge/experience (which I have much respect for), would you comment on my variation? I assume the chart/advisor values are based on a string standard (?) and the values vary with different types of string? Is interpolation of the chart values (assume linearity) acceptable? Are there chart data for other DTs beyond 28,31, 34, 37, and 40?



Hi Gotwheels,


I would like to make some remarks to this message:
There is some safety margin built into the Tension Advisor figures, to avoid that a stringer with less quality or with a machine with a bad tensioner of bad clamps still achieves a good result.

So it is quite possible that your result with the high quality ML100 and good stringing qualities is higher.

But aiming at 31 an getting up to 36 is a little too much.

There is one more thing that can have quite some influence:
You mention “slight pre-stretch”.
The result of pre-stretching the string is that you take the remaining elongation out of the string at a higher tension then the stringing tension.
This has 2 effects:
1) The string will be stiffer and loose less tension during stringing and playing. Because you loose less during stringing this can result in a higher SBS, depending on the amount of prestretch.
2) Because the string becomes stiffer the playability of the string goes down. When the player hits the ball he feels the total elongation so if there is less remaining elongation he feels a stiffer stringbed.

My advises:
- I think that the only reason to use prestretch is when you need a stiff string and you do not have one. In this case you can use a string with more elongation and make it stiffer by prestretching.
- If you want to use the prestretch function lower the stringing stiffness by one class on the Tension Advisor.

There are no values in between the SBS values on the Tension Advisor., you just have to take in between values of the tensions that you calculate.

I hope this is useful to you.

Stringa

[gotwheels]

Stringa, Thanks for the reply. We wannabe stringers benefit so much from your knowledge and experience. I mentioned my light pre-stretch, because I though it would have an impact, but no clue as to how much. I have measured my prestretch at 35-40 lb. for ~ 60 seconds. I have done this for synthetic gut coil memory removal and to reduce tension loss.
I have developed the habit of doing this with synthetic gut and natural gut strings. For me personally, I use a SG as the cross in my poly main hybrids and want the crisper feel without the full poly stringbed. I, also, experience greater overall stringbed stability (DT) over time, than a full poly stringbed.

Thanks again!