String stiffness on TWU vs. RacketPedia

[itischanandlerbong]

Anyone here noticed that the string stiffness data can be contradicting between TWU and RacketPedia? Which one tends to be more true to your experience on court?

An example to illustrate my point, take Head Lynx Tour 1.25 vs. Volkl Cyclone 1.25

Head Lynx Tour 1.25:
- TWU: 218 lb/in
- RP: 1.05 kg/mm

Volkl Cyclone 1.25:
- TWU: 191 lb/in
- RP: 1.13 kg/mm

TWU says Lynx Tour is stiffer, but RP says Cyclone is stiffer. Both databases have their own methods of measurement, so I'm not questioning their methodology. I'm merely interested in which of these databases' measurements reflects a truer to court experience.

 

[Sontheim]

There are a lot of more examples and i also Wonder about this .. MSV Swift...very very soft...rp 1,0

 

[veelium]

Both databases have their own methods of measurement, so I'm not questioning their methodology. I'm merely interested in which of these databases' measurements reflects a truer to court experience.

I'd question their methodology if I knew what they were.
The vagues stories I heard about RP measuring methods weren't great.

 

[TennisJrDad]

I have been more than satisfied with RP numbers and their testing methodology. Based on experience, I have found a high correlation between RP ratings and first hand on court performance.

 

[WYK]

Racketpedia tests the string at a lot of varying tensions, and they also test it in different ways.

How it works?

www.racketpedia.com

TWU states:

• Stiffness (k) is how many pounds force are necessary to stretch the string lengthwise by 1 inch during a dynamic impact.
• Measurements were made with string reference tension of 52 lb with a swing speed for a 120 mph serve.

Either way, you are comparing strings for a general idea of how they might differ. The only real world test is in your racquet.
Both measurements give you a fairly good idea of what sort of string you are dealing with.

 

[jimmy8]

I looked at both for a while. RP seemed more accurate to what I felt. Now I use RP more often.

 

[HeavyHitter]

Anyone here noticed that the string stiffness data can be contradicting between TWU and RacketPedia? Which one tends to be more true to your experience on court?

An example to illustrate my point, take Head Lynx Tour 1.25 vs. Volkl Cyclone 1.25

Head Lynx Tour 1.25:
- TWU: 218 lb/in
- RP: 1.05 kg/mm

Volkl Cyclone 1.25:
- TWU: 191 lb/in
- RP: 1.13 kg/mm

TWU says Lynx Tour is stiffer, but RP says Cyclone is stiffer. Both databases have their own methods of measurement, so I'm not questioning their methodology. I'm merely interested in which of these databases' measurements reflects a truer to court experience.

TWU Data you posted is at 51lbs tension vs RP data you posted is the avg of 10kg~35kg. If you look at RP's 20kg~25kg stiffness only, Lynx tour is stiffer at that tension. TW's data is also more dynamic as it is calculating with the racquet head speed. Where RP's data you posted is static. If you look at RP's "dynamic stiffness" , it correlates similarly to TWU's data.

 

[itischanandlerbong]

TWU Data you posted is at 51lbs tension vs RP data you posted is the avg of 10kg~35kg. If you look at RP's 20kg~25kg stiffness only, Lynx tour is stiffer at that tension. TW's data is also more dynamic as it is calculating with the racquet head speed. Where RP's data you posted is static. If you look at RP's "dynamic stiffness" , it correlates similarly to TWU's data.

Good point, unfortunately I don't have a RP subscription and so only have access to that 1 number they share on stiffness averages. The Lynx Tour full data is available to public but not the Cyclone's.

I take from your response that you find TWU's data to be closer to your on-court experience, than RP's average number?

 

[itischanandlerbong]

I have been more than satisfied with RP numbers and their testing methodology. Based on experience, I have found a high correlation between RP ratings and first hand on court performance.

Thanks! Which RP number do you reference?

Referring to this link (https://www.racketpedia.com/en-GB/tennis-string/head-lynx-tour-grey-125), I see there's an average stiffness number, stiffness at varying tension ranges, and 2 dynamic stiffness numbers.

 

[TennisJrDad]

That was a broad statement of RP in general. Their overall methodology and reporting style for scoring a string in multiple areas (power, comfort, etc). I look at the raw numbers you are referencing, and usually focus on the static numbers for the specific tension I string at, as well as average and dynamic.

Overall, I have found RP to be the most highly correlated database with actual on court real world experience.

Thanks! Which RP number do you reference?

Referring to this link (https://www.racketpedia.com/en-GB/tennis-string/head-lynx-tour-grey-125), I see there's an average stiffness number, stiffness at varying tension ranges, and 2 dynamic stiffness numbers.

 

[AdrianS]

I've posted the same question few days ago.

Here is what I've learned so far:
RP Static tension is a direct measure of how the string tends to maintain or not, in the first 300 secs (5 min.) after tensioning, the initial tension value.
In case of a string with poor static stability, there will be a pronounced decline in the tension value, which is always concentrated in the first 30-60 secs. after stretching and then stabilize in an almost constant value after 180-240 secs.
In the case of a strings with excellent static tension stability, the tension drop will be contained in about 15% (+/- 2%).
A string with intermediate holding value will return close to 20% (+/-2 %)

Take away:
The static tension stability value, however connected, is not always indissolubly linked with the dynamic tension stability and in some cases, there may be strings with a significant static tension drop, which will not show a decay and change in behavior under dynamic tension action.