Recently I have sent my racket to be strung at 27lbs with 10% prestretch (Nanogy95) and when I collected it it was about 29.3lbs (measured with stringster app). I have been requesting prestretch on and off just for testing the difference and noticed this usually happens whenever I ask for 10% prestretch. Though one thing to note was that I collected the racket just about an hour or two after it was freshly strung... Just wondering whether this is normal? Or stringster is messing with me lol. I have another same racket with the same string but done without prestretch also at 27lbs. Been using it for about 3 weeks. stringter tells me its about 24lbs now and it does sound lower pitched than the freshly strung one.
It is especially important that your stringer strings constantly. Next time you can just let it do a little bit more or less. Normally a 27lbs stringjob should be a 27lbs stringjob (direct after stringing). Then the string lose 1lbs within 24hours without playing and 1lbs after the first sessions. With prestretch the tension loss should be less. Maybe his machine just pulls a bit more or he strings 1-2lbs more, because then later the "right" string tension is on the customer's racket? There are people who complain when 23lbs is at stringster and 24lbs are wanted... But I wouldn't trust the Stringster app either. Depending on the racket, string, smartphone and settings, something is often displayed incorrectly. So trust your feeling and adjust the stringing.
I have never seen a stringing app that works. We calibrate our machine every day. We have tested every stringing app we have ever seen and not one of them has matched up to our calibrated machine. Frankly, I don't think any of them work.
Tension loss is between 15 and 20 % right off the machine. So it also depends when you measure the racket. Don't care too much about what an app tells me, feel is important.
I think 20% is overestimating the tension loss straight off the machine. My racquets are strung at 31lbs and I can feel it is definitely 30+lbs tension for at least a week (BG80/85). Whether stringster is accurate or not I'm not sure, but it also records 31-32lbs. If assuming a 20% loss straight off the machine (6lbs) then the strings should feel like 25lbs but they definitely don't feel like 25lbs.
Are you sure any combination would result in a 20% tension loss straight off the machine? You're saying someone asking for 25lbs will get 20lbs fresh off the machine?
I can't remember exactly, but I once measured it by using the ping in Hz as an indication of string tension. Way back I was using Gosen R4X110 as a string and it lost about 15 to 20 % iirc in the first few days without playing. I also noticed the difference when I strung my racket straight before training compared to when I strung it a few days before.
FME the tension drop is higher for high tension than for low tension. I observed tensions drops after 24h without play of 120 Hz of a 31 lbs jobs with BG65. My BG80 drop 120Hz after around 2-3 weeks which is below 10%. The BG65 jobs of 10kg normally dropped just 100Hz in total. Really disappointing was Zymax for me. Can remember the drops, but they were high and near 10%. IMO 15-20% is a bit on the high side, but really depends on the string and tension.
A 10% drop over 2-3 weeks for BG80 would be more consistent with my experiences. I have to say I'd probably avoid any string that has a 15-20% tension drop within 24hrs.
With prestretch you'll get higher tension right there when it still sits on the machine, and you will see less of a drop after it leaves the machine. Sent from my StringLab using TapaTalk. Cheers, FeatherBlaster
It also depends on what your stinger recognizes as 27lbs. It could be 27x27, 27x29, 26x28, or 26x28.5 and these can result in different frequencies as reported by the stinging app. Overall it shouldn't matter too much as long as you enjoy the way it plays when you're on the court and when you do get it restrung with the same requests, it is consistent.