happyandbob
Legend
I bought a subscription to the racketpedia DB to compare their string performance data* to the TWU professor's data. (* I know that RP claims their data is based on lab tests, but their site has scant details on what the tests are and what the 0-100 ratings actually represent)
I thought tension maintenance might be the most straightforward measurement and perhaps the one likely to have the best alignment so started there. RP tracks every metric on a 0-100 index, so I converted the TWU metric "Tension Loss Pct" into a percentile for each string based on all the percent tension loss measurements in the TWU database. (e.g. Babolat RPM Blast 16 has 45.9% tension loss, which corresponds to 21st percentile among all TWU strings for tension maintenance)
Comparing some selected strings between the two on tension maintenance:
There are a few strings that seem aligned, but really it's all over the place. The first thing I wonder is if RP is rating strings only compared to other like strings -- e.g. does RP consider Focus Hex to be a 100 at holding tension vs all other poly strings? Second thing is how much color seems to impact tension maintenance. Is the difference between the RP tension maintenance due to RP testing black Focus Hex and TWU testing an alternate color. There are color differences in tension maintenance even in the TWU database where Multifeel 16 is 78th percentile for tension maintenance but Multifeel Black is 90th percentile.
Seems crazy though. RP thinks Solinco Outlast 17 is 100 for tension maintenance, but TWU tests show it holds tension terribly at the 11th percentile.
I thought tension maintenance might be the most straightforward measurement and perhaps the one likely to have the best alignment so started there. RP tracks every metric on a 0-100 index, so I converted the TWU metric "Tension Loss Pct" into a percentile for each string based on all the percent tension loss measurements in the TWU database. (e.g. Babolat RPM Blast 16 has 45.9% tension loss, which corresponds to 21st percentile among all TWU strings for tension maintenance)
Comparing some selected strings between the two on tension maintenance:
| String | RP "Tension holding" | String | TWU "Tension Loss" Percentile (higher is better) |
| Ashaway MonoGut ZX 127 | 60 | Ashaway MonoGut ZX 16 | 16 |
| Babolat VS Touch Natural 130 | 100 | Babolat VS Natural ThermoGut 16 Touch | 88 |
| Head Velocity MLT Natural 125 | 90 | Head Velocity MLT 17 (1.25) | 97 |
| Isospeed Cream Beige 128 | 80 | IsoSpeed Cream 17 (1.28) | 59 |
| Kirschbaum Max Power Grey 125 | 90 | Kirschbaum Max Power 17 (1.25) | 71 |
| Msv Focus HEX Black 118 | 100 | MSV Focus Hex 17L (1.18) | 60 |
| Msv Focus HEX Black 123 | 90 | MSV Focus-Hex 16 (1.23) | 55 |
| Solinco Confidential Black 130 | 100 | Solinco Confidential 16 (1.30) | 75 |
| Solinco Hyper-G Green 120 | 95 | Solinco Hyper-G 17 (1.20) | 64 |
| Solinco Outlast Red 120 | 100 | Solinco Outlast 17 | 11 |
| Solinco Revolution Blue 120 | 95 | Solinco Revolution 17 | 12 |
| Tecnifibre Black Code 4S Black 125 | 85 | Tecnifibre Black Code 4S 17 (1.25) | 58 |
| Tecnifibre Multifeel Natural 125 | 60 | Tecnifibre Multi-Feel 17 (1.25) | 80 |
| Tecnifibre Multifeel Natural 130 | 75 | Tecnifibre Multi-Feel 16 | 78 |
| Yonex Poly Tour Pro Yellow 125 | 70 | Yonex Poly Tour Pro Yellow 16L (1.25) | 20 |
There are a few strings that seem aligned, but really it's all over the place. The first thing I wonder is if RP is rating strings only compared to other like strings -- e.g. does RP consider Focus Hex to be a 100 at holding tension vs all other poly strings? Second thing is how much color seems to impact tension maintenance. Is the difference between the RP tension maintenance due to RP testing black Focus Hex and TWU testing an alternate color. There are color differences in tension maintenance even in the TWU database where Multifeel 16 is 78th percentile for tension maintenance but Multifeel Black is 90th percentile.
Seems crazy though. RP thinks Solinco Outlast 17 is 100 for tension maintenance, but TWU tests show it holds tension terribly at the 11th percentile.
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