Is there a viable alternative to RacquetTune on Android (i.e. supported for string factors or equivalent)?

[Pinceptin]

I just started my own stringing journey by purchasing a drop-weight machine.

Up front. I'm not trained, and will not be using this to make any money, it's just for personal use. (The expense of restringing in London is somewhat prohibitive once you factor in travel and a turnaround time of 3-4 for drop-off/pick-up services). As someone who is starting to get more serious about tennis and wanting to experiment with different strings/tensions in a racquet, and also being an engineer by trade who likes tactile and manual projects, the idea of doing it myself was really appealing. However, on the budget I have going electronic was out of the question so I went for a drop weight machine.

Anyway, I stumbled on RacquetTune in an article of ways to measure string tension. Seemed like a really nice way to be able to test my work once I've strung a racquet, plus then tracking tension loss over time compared what I can actually feel during play.

The first measurement I did was quite a way off; 4lbs difference (registered 48lbs compared to the 52lbs I had set the machine at). I then tested a racquet that was strung at 53lbs a few weeks ago by a professional - it's had maybe 20 hours of play so would expect some drop-off. It measured 43lbs though, which feels like a lot. (For reference, it was strung with Solinco Revolution 16G)

I did some research and, unsurprisingly the most valuable knowledge came from these forums a few years ago. I was missing a crucial piece of information - the String Factor. This isn't referenced anywhere in the Android App, all you get is a default value. I understand you can calculate this yourself but I'm not sure how, or if I have the necessary tools to do so. Without this information I cannot be sure of getting viable readings.

The rest of the app is very poorly supported also. The embedded link for the help guide returns a 404 Not found page, and the appmakers website now only references the iOS version. It appears they never fully ported it over to Android, and have since abandoned all further Android support and development. (However, they are still charging for the app!)

I can't find any source of reference string factors anywhere online, so am now looking for an alternative. I'm loathe to trust reviews on various websites as this was how I was directed to the Android RacquetTune app in the first place, so thought I would reach out to the forum to see if anyone is aware of a decent competitor that is actually supported in the Play Store.

thanks for any help

 

[esgee48]

The developer developed RT for iOS and is supported over there. The code was ported over to Android by a 3rd party. Anyway, string factor is basically grams/meter after the string is installed at ref tension. It is not based on an unstretched piece of string. The best way to explain it is first install your string job. With your left over string, stretch it at your ref tension since you are using a DW. Now measure the mass of the string and divide by the length of the stretched string. This is a reasonable approximation of string factor. Out of the package, poly may have a SF or 1.7, but when stretched have a SF of 1.6. The delta is even worse with SG and multifibers. Note the number, what string and tension. This is what the developer defined in the iOS version. He also lets you pull the string at ref tension, ping it and let the app figure your string factor in the iOS version.

Try googling "android string tension test app". They're out there, but I cannot attest to their usefulness as I use iPad and iPhone.

 

[Pinceptin]

The developer developed RT for iOS and is supported over there. The code was ported over to Android by a 3rd party. Anyway, string factor is basically grams/meter after the string is installed at ref tension. It is not based on an unstretched piece of string. The best way to explain it is first install your string job. With your left over string, stretch it at your ref tension since you are using a DW. Now measure the mass of the string and divide by the length of the stretched string. This is a reasonable approximation of string factor. Out of the package, poly may have a SF or 1.7, but when stretched have a SF of 1.6. The delta is even worse with SG and multifibers. Note the number, what string and tension. This is what the developer defined in the iOS version. He also lets you pull the string at ref tension, ping it and let the app figure your string factor in the iOS version.

Try googling "android string tension test app". They're out there, but I cannot attest to their usefulness as I use iPad and iPhone.

Thanks for the quick reply esgee48. Wow, that's crazy that it was ported by a 3rd party. I'm assuming this was with the permission of the developer at least? (it doesn't change the fact the app isn't supported, but I would quickly switch from feeling annoyed at having purchased an incomplete product to feeling horrified that I'd paid someone who stole someone else's work!)

I'll give the string factor thing a go. That's really helpful on how to calculate it as well.

Follow-up question if you have a moment. I know that RT doesn't measure the string tension but rather the racquet tension. What I don't know is how much these numbers should differ by. I know it will change depending on a number of factors, but should the two figures be roughly the same at least. Are we talking +/- 5%, 10%, 20%, for example?

 

[esgee48]

It was ported over with the developer's permission. However, he stated he was not going to support it when it was done. His issue with android systems was the hodgepot of brands use with the microphones. He understood Apple and their control so he could only have to make the app once.

The string factor works when you use it to ping a single string and for the string bed. Both are frequency based. With the iOS version, it can calculate the SF when you tell it what tension, length, etc was used. The same SF is used for pinging the string bed. I routinely come with in 0.1# of ref tension when I pull racquets off my machine. The nice part about this step is when I do not come within spec when finished, I know I forgot to do something like clean my clamps or gripper. I do not carry many strings, basically SG only and can reuse the SF. Clients who give me their poly, etc., strings are normally repeat clients asking for the same tension using the same string. If I have the SF, I will use it otw I will measure it.

What you could do is if you trust your technique to be precise and accurate, you could vary your SF until it approximates your overall ref tension. Then note that number. However, you must be sure about your technique because there are many places you can lose tension when stringing.

 

[Pinceptin]

It was ported over with the developer's permission. However, he stated he was not going to support it when it was done. His issue with android systems was the hodgepot of brands use with the microphones. He understood Apple and their control so he could only have to make the app once.

The string factor works when you use it to ping a single string and for the string bed. Both are frequency based. With the iOS version, it can calculate the SF when you tell it what tension, length, etc was used. The same SF is used for pinging the string bed. I routinely come with in 0.1# of ref tension when I pull racquets off my machine. The nice part about this step is when I do not come within spec when finished, I know I forgot to do something like clean my clamps or gripper. I do not carry many strings, basically SG only and can reuse the SF. Clients who give me their poly, etc., strings are normally repeat clients asking for the same tension using the same string. If I have the SF, I will use it otw I will measure it.

What you could do is if you trust your technique to be precise and accurate, you could vary your SF until it approximates your overall ref tension. Then note that number. However, you must be sure about your technique because there are many places you can lose tension when stringing.

Oh absolutely. And like I said I've just started my stringing journey so am making no assumptions about how accurate I am at present - things like how much additional pull I should give to the last mains/crosses to account for losing some when tying knots, or offsetting mains/crosses by a given amount to account for elongation and friction respectively.

That's actually the reason I looked forwards to the app in the first place, as it would be great to string a racquet and then have some way of testing it to see how close the end result is to what I intended.

You said that your tension on the stringbed usually comes in within 0.1# of the reference tension? So you're saying if my technique is good then I should get a close number in the tension that RT measures to the tension I set the machine at then. That's useful to know, thank you. I was worried that there was something else I was missing like the finished racquet tension being expected to be different to the individual string tension. I know there will be a lot of room for error anyway with the drop-weight, but at least I can now know what number I'm aiming for.

Thanks again

 

[esgee48]

I take my time and pull for long periods, between 5-10 seconds, to assure I pull out static tension losses. I do this for mains and crosses. I move my crosses under tension to make sure that I remove as much tension loss due to friction as possible. I wipe down and clean the frames before stringing. My wipedown include wiping the string channels to rejuvenate the plastic and to lubricate. A 16x19 will take me~30-35 minutes where as others can to it in ~20 minutes. With multifibers, I will be within 0.3-0.4# 95% of the time. Poly and SG will be within the 0.1# range 95% of the time. 12-24 hours after stringing, tension may drop between 1 and 3# if I have done everything right. Hybrids are more questionable because you have 2 string factors in the iOS version. Certain string material like Kevlar will not give accurate reading because they do not ping well.

You can shoot for ref tension, but most users are happy getting within 1# of ref tension. Just be methodical and consistent. The best compliment is when the client receives their racquets back and ping them, they sound exactly the same to their ears. I will RT the racquets and tell them they are at ref tension - X #.

 

[Casper777]

TennisTension works great for me!