Does String Get Thinner Under Tension?
The other day, a customer told me he was sure the string in his freshly strung tennis racket looked thinner than the string straight off the reel.
I was sceptical. So I decided to test it.
Out came the micrometer – the same one I’ve had since my engineering apprenticeship – and I measured the string straight off the reel: 1.27mm.
Then I clamped it under load – 52lbs, a common string tension for tennis rackets. Measured again: 1.26mm.
So, fair play – he was right. The string does get thinner under tension.
But here’s the thing – 0.01mm might sound like a big deal, until you put it into perspective.
For comparison, I measured a hair (yes, from my belly – don’t ask) and that came in at 0.04mm. So the change in string gauge is about a quarter the width of a human hair.
Perceptible to the human eye? I don’t think so. But technically, yes – the string does get thinner when pulled tight.
It’s one of those moments where I’m glad I work alone in the shop. But also a reminder that there’s a lot of science in a good restring.
