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Old 09-19-2012, 03:55 AM   #26
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Originally Posted by kaiser View Post
I compared the stringbed and sweetzones of the BLX Pro Staff 6.1 95 to the PS90 in TWU (posted before in another thread):

Measurement .......... BLX PS90 ... BLX PS95 ... Difference
Spin Window (in) .......... 5.71 ........ 5.5 ......... 0.21
Location width (in) ........ 9.29 ........ 9.13 ...... -0.16
Power > 20% (in^2) ..... 26.5 ........ 24.0 ........ 2.5
Power > 30% (in^2) ..... 16.0 ........ 13.7 ........ 2.3
Power > 40% (in^2) ....... 4.7 ......... 2.7 ........ 2.0

This suggests that in terms of EFFECTIVE headsize, the PS95 would actually be LESS forgiving than the PS90! Does that tally with your experience, Fed? Of course, if you lead up the PS95, its sweetzones will increase, but stock we're talking differences of 10-75% in favor of the PS90 here...
The sweetzones are primarily a function of swingweight, with twistweight and stiffness coming in a distant second and third. The TWU Power Potential data shows that there is a nice, tidy relationship between swingweight and Power Potential of 10 swingweight units = 1.0 Power Potential units. Looking only at the sweetzones (20%, 30%, 40%) makes it hard to compare sticks with very different swingweights. If you switch to the location view, you see that the 90 has Power Potential of 41.2% in the center of the stringbed and the 95, 38.8%. The swingweights of the specimens tested were 324 and 303, respectively. So we can add 2.1% to the 95's number to get 40.9%. In other words, this is what it would be if we added lead tape to bump the swingweight to 324. So matched, the 95's PP is slightly less than the 90, which is probably down to the slightly lower stiffness of the 95.

So the numbers are actually about what you'd expect. You can do the same addition at other impact zones above, below and to the sides of the stringbed center to project what the Power Potential would be with lead tape added, but it because a less precise approximation outside the center due to how twistweight and local stiffness change depending on lead tape location.

Anyway, Fed K's perceptions seem to belie all this, but then again he may be experiencing and reporting something quite different from the objective quality of Power Potential (Apparent Coefficient of Restitution).

I was surprised to find that at the middle of the stringbed (21 inchfrom buttcap) TWU lists the PS95 as only 0.16 of an inch wider (4 mm) than the PS90! Could anyone who has access to both rackets check this? Much appreciated!
Yeah, I would like that too. I don't think the measurements for the 90 are correct. I know the K90 measurements are correct, and TWU has that .25 inches narrower 21 inches from the buttcap than the PS90. I haven't measure the PS90, but I've seen them and didn't notice any difference in headshape.
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