Yo-yo science experiment challenge: how much does your string stretch in play?


I have an idea for a yo-yo science experiment around strings and how much they stretch in play.

  • Take out two brand new strings, from the same vendor in the same batch.
  • Make sure they are both exactly the same length – you may need to cut to preferred size, but be sure to cut both of them!
  • Put one string on your favorite yo-yo; put the other string away in a drawer.
  • Play intensively with that yo-yo for 3 days.
  • At the end of the 3 day period, measure the difference in length between the played and unplayed string.

How much do strings stretch? We can find out… with SCIENCE :woman_scientist:

I’m also curious if the amount of stretch varies by brand, or by type (nylon, nylon/poly, poly).

What did you get in the mail this week?
LF Cheap Shutter
(Tyler) #2

I know poly stretches a good bit. I always pull mine to stretch them before I make my loop, they still stretch a little after that, but keeps my string length more consistent over the life of the string.

(Jacob Waugh) #3

Tyler Severance said that he pulls his string as hard as he can before playing with it. (to stretch it)


I still think play will stretch it even more. Let’s SCIENCE THIS and find out!

(Ethan Evans) #5

I do that too


You could have a third string that you give a few good stretches to. But really, couldn’t you just use one string? Measure, stretch, measure, play, measure… or just measure, play measure.

Maybe two stings: 1) measure, play, measure. 2) measure, play, stretch, measure, play, measure.

(Tyler) #7

I’ll measure when I next throw on a new string!


More data points the better


More accurate to measure the same string. Though I suppose the string in the drawer is the control? I just don’t think it’s needed, as you could just measure it. Unless you’re testing to see if it might change as well?


You could! But it’s more SCIENTIFICALLY DRAMATIC to lay the two next to each other, side by side, so you can visually compare the difference of old and new!

(Tyler) #11

If you want to get really scientific you could test a handful of strings to see if you get a variance in your data (which you probably would).


This would take forever with ammo string. Ammo lasts eternity…

(YoYoStringLab) #13

Do we untie the loop to compare the used string to the unused string? How do we measure, pull taught, let it lie straightened, but untouched? What if one of the strings was inadvertently partially stretched in manufacturing relative to the other string? I am leaning towards liking the testing of one string vs. two.


I love your guys sting, it’s all that I ever use!


There is a distinct lack of SCIENCE :test_tube: in this topic.

In order to encourage more SCIENCE :test_tube: I make the following offer: post comprehensive photographic evidence of your science experiment and its results, as documented in the first post… and I got a brand new Shutter here with your name on it. Best science-er wins. CONUS only please!

Let the SCIENCING :test_tube: BEGIN!

(Tyler) #19

When do we have until? I already started one and wrote everything down, but I can start a new one and take pictures this time.


At least a week!

(Tyler) #21

Also, you’re freakin awesome. Always doing these contests and giveaways - not to mention always sending people yoyos for no other reason than to send them a yoyo. Glad I found these forums!

(Tyler) #22

After one week of testing, I am back with my results!
Strings and yoyos used:

  1. Zipline Hulkenstein (green) on a YYF Shutter
  2. Homebrew string from @Kieran (pink) on a TP Houska Dry
  3. Buddha XL (red) on a Replay Pro

I usually pre-stretch my strings before tying a loop, but for the sake of the experiment I did not do this. As such, I did not hold the strings tight during the first measurement, but they are accurate within a 1/4 inch.


I played approx. 4 hours with each string/yoyo throughout the week. The pink and red strings are very similar in feel and thickness, whereas the blended color Zipline string is much thinner, and seemed to have less bounce to it right from the start. Noticing this, I hypothesized that the green Zipline string would be more resistant to stretching over time, being a generally longer lasting string than bulk poly.
To get a variation of results from my two similar strings, I played one exclusively indoors (pink) and the other I used exclusively at my work in a machine shop (red). I thought the dirt and oil likely to get on my string at work could potentially yield different results.


The red string, starting at approx 45 inches stretched almost 3 inches by the end of the week.
The pink string, also starting at approx 45 inches, stretched just over 2 inches by the end of the week.
And lastly the green string, starting at approx 44 inches, stretched only just over an inch by the end of the week. I feel it is also worth mentioning the green string could still be played longer, and could potentially stretch some more by the end of another week of play.

In conclusion, the Zipline string held up better throughout a week of play, and stretched the least distance. The bulk poly Buddha XL string would probably have gotten changed already if I wasn’t doing this little experiment, having stretched the most over the course of the week.



Also we need some NYLON people to run this test! Your potential prize for your scientific effort is, as per the above, one (1) mint Shutter.