Strings Quality Control

A few friends whom I string for regularly usually keeps a reel or two with me.

Right after playing with a fresh stringjob, this friend called and asked if I had changed anything, or pranked him (link).

I assured him I did not and did exactly what he instructed. But he claimed the strings played very differently.

My stringing mentor used to say, "When in doubt, check EVERYTHING!" So I did:
- Correct strings used --> ok
- Racket dimensions before and after stringing --> ok
- Clamps slippage --> ok
- Dropweight tension alignment --> ok
- Tension settings --> ok

He claimed the strings played a little dead, like it was over-tensioned.

So I asked:
- Did he leave the newly strung racket in a parked car?
- Did he change to a different brand of tennis balls?
- Was he playing in a different tennis court?
- Was he playing with different partners?

Strangely, everything was the same. Even his regular buddies commented how poorly he delivered all his shots that session!

Then I checked the strings. It was from a new reel he just bought from a very reputable online shop, exactly the same source as the previous reel. So it seemed legit.

Everything appeared in order when comparing the logos, fonts, packaging, string colour, texture, etc.

Out of curiousity, I measured the string diameter and found it 0.03mm thinner than the leftovers from the previous reel! Aha!

Samples of both were cut out, labelled carefully and tested for its elongation properties on the stringing machine, like this.

Then the answer came!

At the same tension, both fresh pieces of string differed in their stretch by almost 20%. This is a huge difference by itself, and together with the 0.03mm thinner diameter, it could totally be passed off as an another string! 

Either the QC was off, or the string factory had labelled and packaged the strings wrongly. Or the formula was tweaked! 

If you check online forums, this seemed to happen once in a while. Reports of different coloured strings playing differently were more common.

To save on shipping, my friend bought 3 reels of this premium string. The total amount spent was more than enough to pay for three brand new Babolat rackets! 

Thankfully, after sending photos of the diameter discrepancy, the shop offered to grant a full refund via credits, less shipping. The downside was, the 3 reels must be shipped back at our costs.

As for me, it was a great relief to be vindicated.