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Old 01-07-2014, 08:15 AM
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AMA-69405
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Originally Posted by aeajr View Post
I have seen these theoretical tables before. No problem with them as I have not tested everything he has listed. However I have tested and used the Aerofoam 3M, the Pinnacle L and the Dynaflite HD. On those three his theoretical numbers come up 2-3 pounds below the actual measured pull that I got during tests at the field using a spring scale. For example the chart predicts 17 punds for the Aerofoam 3M. We have 3 at the field and they all test at 19 pounds using two different scales. That 2 pounds is about an 11% variation from the predicted. Not bad and it is probably better to err on the low side and that is how I see these tables, about 10 to 15% low.
In every case where the manufacturer/retailer provides tension numbers, the chart agrees within about 10%. Sometimes high, sometimes low, but always somewhere between spot-on and plus or minus 10%. Keep in mind that temperature and rubber age can affect readings, so I would say your 11% delta is certainly within the range of expected testing deviation.

Originally Posted by aeajr View Post
The absolute numbers may not be exactly right but they are close enough and the strength ratio of one to the other is probably pretty accurate.
Precisely... that's why I put the chart together. Otherwise it's difficult for a novice to understand, for instance, why the Dynaflite Heavy Duty, Hobby Lobby 2 meter, Hobby King 8 mm, TheraBand Red, and the NSP Medium are all the same device, practically speaking.
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