I’m wearing an old pair of tennis shoes and they’re at the point when the shoelaces always come untied for no reason. Why do they do that? New shoelaces don’t seem to ever just come undone. I’m guessing the fabric wears off and they have a harder time “clinging” to each other. But it seems like there should be more to it. Am I overthinking it? Stupid shoelaces.
My guess is that you have an incorrect knot.
A “square knot” is inherently unstable, and scorned by the knot expert websites.
It may hold when there is a lot of friction, but when slack, as you have surmized, it tends to twist and unravel.
If you Google on “knot tying pictures” you will find several good sites that go through the specifics.
Since I modified my shoe-tying technique approximately 10 years ago, I have never had my shoes come untied on their own. The only difference is when you go to loop around your thumb and index finger, you go around twice. The trick is to make both loops tightly around your fingers. The rest of the knot is the same as usual. It won’t undo itself but it will come undone if you pull on the laces.
The above was from some book like “Knot tying for klutzes”.
He’s not trying to haul a human up a mountain or secure a motorcycle into a pickup. A square knot (with loops on each end) is just fine for shoelaces, and has been the standard shoe tying knot for untold decades.
Now, it may well be that an incorrect knot is part (or all) of the problem. The typical incorrect knot in this case is the granny knot .
Well, what I was getting at is why the laces seem to lose their power to stay tied the older they get. I never have trouble when they are new but over time they just give out. I don’t think I’m the only one to have noticed this. Maybe I am. I was hoping for a scientific explanation for this phenomenon.
I do appreciate all the knot links though.
Guesses:
- Grime makes them slicker
- Having been stretched tighter, the weave of the threads will be sticking out less so there is less friction, as well as the angle steeper so when the threads slide over another surface they will be less likely to catch (i.e. less friction.)
I tried doing some searches on ropes, and I get the impression that there have been lots of studies done–but that finding one would be difficult unless you were in the rope industry or a have lot of time to spend with google.
I have heard that coating them with a little shoe polish can help the knot stay tight (although you might need to wear gloves when you tie them…).
I’ll cast my vote in the “fibers getting older and more supple” camp.
For this reason, I always tie double knots on my running shoes (just like mom did when we were kids) – after a few months, the shoes develop an annoying tendency to untie themselves a few miles into a perfectly decent run.
On top of that, the type of lace seems to be a factor. All the running shoes I use seem to have a kind of plump tubular lace instead of the traditional flat (but still tubular) lace. These plump laces don’t seem to hold as well.
Certainly the laces may be getting slicker as the smaller fibres wear off the outside and you are left with the ‘core’ of the lace. Washing them might help.
I do have to agree with the previous posters who suggest it is the knot that is the culprit. Check out Ian’s Shoelace Site for some alternative ways to tie your laces. He also has a brief section on why they come undone. Chances are that you are creating a granny knot rather than a square know (as suggested earlier). The easy way to tell is to look at the bows after you have tied the knot. If they lay across the shoe then you shouldn’t have a problem, but if the bows lay up your ankle and down the lace, then it is tied incorrectly and will likely come undone.
It could be my knot-tying technic, I’m not ruling that out but what I’m getting at is why does this happen. My shoes are 3-plus years old and I’m just now having these untying problems and it happens to most of my shoes over time. The question really wasn’t “help me with this problem” but “why does this happen over time”.
And for seosamh suggestion about coating the laces with shoe polish, you know, I really appreciate your help, but if I get that hard up, I’ll just buy some new ones. And please don’t take this as an insult. Just thinking about going to all the trouble to apply shoe polish to my laces really strikes me as funny. But this could be good advice for new laces that keep coming undone (I never had that problem however).
As for relearning to tie my laces, I’m just too old for that. It would be like relearning to wipe my butt. I’m just set in my ways. Especially for something that isn’t a problem (if you could call it that) until my laces are several years old.
As others have stated, the shoelace smoothing out and losing friction is probably a factor. Also, maybe the lace in the knot section has been compressed and stretched enough so that it doesn’t re-expand slightly like it used to when released. Such re-expansion would help keep the knot tight.
I tied my shoes with a granny-type loop knot until I was an adult (I learned wrong and finally figured out the right way), and my knots stayed tied. However, I started having problems a while ago when I bought a style of shoe that uses a slightly waxed lace. After a couple of years, to keep the knots tied I have to tug on the shoe end of the loops with extra firmness and actually work the lace from side to side a bit.
I’m sorry, I didn’t mean to ignore all the other posts. I’m sure it’s a combination of several factors. I never thought of the knot section being compressed over time and not being able to re-expand enough to hold the knot. For some reason, this really strikes me to be the main reason. It just makes sense.