Question 1

Why does this web app exist?

Accepted Answer

Major companies rarely release objective, quantifiable data about their tennis strings, instead relying on vague marketing terms like 'soft', 'hard', or 'responsive'. I built this app to provide transparent, measurable hysteresis data so players can compare strings based on actual physical properties rather than marketing hype.

Question 2

How do you measure the strings?

Accepted Answer

I use a Stringway T92—perhaps the only stringing machine capable of this specific test due to its permanent, precise pull and the ability to adjust tension seamlessly mid-pull. I measure elongation with a high-precision caliper (0.01mm accuracy). The base string length at 10kg is roughly 20cm, ensuring a high-resolution measurement (longer is better for accuracy).

Question 3

Are there ads or trackers on this site?

Accepted Answer

No. This website has absolutely zero ads and zero tracking. It is built to be a clean, privacy-respecting tool for the community. If you appreciate the ad-free experience and the effort put into testing, you can support my work via Ko-fi!

Question 4

How can I request a specific string to be tested?

Accepted Answer

Buying and testing strings takes time and resources. If you want a specific string tested that isn't on the list, the best way is to commission a test by supporting me on Ko-fi.

Question 5

What does a wider hysteresis loop mean in the graph?

Accepted Answer

The graph shows a hysteresis curve: tension starts at 10kg, goes up to 30kg, and drops back down to 10kg. A wider loop means the string suffers from higher tension loss (plastic deformation) after a severe impact. Strings with a narrower loop maintain their tension and playability longer over time.

Question 6

What does the slope of the curve tell me?

Accepted Answer

The steepness of the curve correlates directly with the string's stiffness. A steeper curve means the string stretches less under higher tension, feeling stiffer upon impact. This usually translates to more control but less power and comfort.

Question 7

How many strings have you tested, and which brands are included?

Accepted Answer

As of 2026, I have tested 100+ strings from 6 brands: Pro's Pro, Wilson, Solinco, Luxilon, Yonex, and Babolat. Tested in Finland. I plan to expand coverage to Tecnifibre, Head, Kirschbaum, and more.

Question 8

Does polyester string cause tennis elbow?

Accepted Answer

While technique is the primary cause, stiff polyester strings transfer more shock to the arm. You can see this in the graph: stiffer strings like Luxilon ALU Power have steeper slopes. Using softer alternatives like Yonex Poly Tour Pro or Solinco Hyper-G Soft can help mitigate arm issues.

Question 9

What is string tension loss and why does it matter?

Accepted Answer

Tension loss happens when a string is stretched during impact and doesn't fully recover its original length (plastic deformation). In the graph, this is the 'hysteresis loop' width. Strings like Babolat RPM Blast lose tension differently than Wilson Natural Gut, affecting long-term playability and control.

Question 10

Which string should I use for a hybrid setup?

Accepted Answer

A popular hybrid setup uses a softer multifilament or natural gut in the mains for comfort, and a polyester in the crosses for spin and control. You can compare the stiffness of different strings in this app to find the perfect pairing.

Question 11

What is the difference between polyester, multifilament, and natural gut?

Accepted Answer

Polyester is stiff, durable, and offers maximum spin. Multifilament is made of thousands of micro-fibers, offering a soft feel and power similar to gut but at a lower price. Natural gut offers unparalleled comfort, tension maintenance, and power, which you can visualize in our elasticity graph.

Question 12

How does string gauge affect performance?

Accepted Answer

Thinner gauges (like 17 or 18 / 1.20mm or 1.15mm) offer more spin and a softer feel, while thicker gauges (like 15L or 16 / 1.35mm or 1.30mm) provide more durability and control. You can use the gauge toggle in the app to compare.

Question 13

What tension should I string my racket at?

Accepted Answer

The average ATP tour tension is around 23-24kg (~52-54 lbs). The reference tension in our algorithm is built around this average to provide realistic stiffness metrics, but your ideal tension depends on your racket and playing style.

Question 14

What is the best arm-friendly tennis string?

Accepted Answer

The most arm-friendly strings are natural gut (like Wilson Natural Gut) and soft multifilaments. If you prefer polyester, look for 'soft' variants or co-polys designed for elasticity. You can search 'soft' in our app to see the most comfortable strings based on lab data.

Thanh's String Elongation Lab