Head to head

Babolat SpiralTek 17 vs Tourna Quasi-Gut Armor 17

They split the measurements 2–2. The widest gap is ball bite, where Quasi-Gut Armor 17 is 55 percentile points ahead. Every figure is a testing-machine result at a fixed reference tension.

Measured, side by side

Babolat

SpiralTek 17

Nylon · 17 ga

Tourna

Quasi-Gut Armor 17

Nylon/Polyester · 17 ga

Stiffness lower = softer, kinder on the arm
14912th pct
1447th pct
Tension loss lower = stays where you strung it
178th pct
1810th pct
Energy return higher = livelier, more free power
9381st pct
9381st pct
Spin potential higher = more spin off the string bed
5.671st pct
5.671st pct
Ball bite higher = grabs the ball harder
0.41836th pct
0.54890th pct
String friction lower = strings slide and snap back
0.07411th pct
0.09759th pct

Bars are percentile against all 788 strings, and the marked side is the one that measures better, which is not always the one you want. A firmer bed is worse for your elbow and better for your control, and no measurement knows which of those you came for.

Which one wins, by problem

Each string's standing on the site's rankings, out of every measured string in the database. This is where a comparison stops being arithmetic and starts being a decision.

Swapping between them: what tension?

Bed stiffness is published at one reference tension, so the only honest conversion is to scale it. These are starting points from 52 lb, not prescriptions. The calculator takes your own tension.

Coming from SpiralTek 17 at 52 lb

String Quasi-Gut Armor 17 at 53.9 lb 24.4 kg

Coming from Quasi-Gut Armor 17 at 52 lb

String SpiralTek 17 at 50.2 lb 22.8 kg

Hybrid: what if you used both?

Estimated, not measured. No hybrid combination has been tested as a bed. These figures are the two strings' own lab measurements weighted by how much of the bed each one actually is. Treat them as a guide to which way a pairing moves, never as lab data.

SpiralTek 17 mains / Quasi-Gut Armor 17 crosses

Stiffness10th pct · 1 measured
Tension loss9th pct · 1 measured
Energy return81st pct · 1 measured
Spin potential71st pct · 1 measured
Ball bite49th pct · 1 measured
String friction22nd pct · 1 measured

Quasi-Gut Armor 17 mains / SpiralTek 17 crosses

Stiffness9th pct · 1 measured
Tension loss9th pct · 1 measured
Energy return81st pct · 1 measured
Spin potential71st pct · 1 measured
Ball bite86th pct · 1 measured
String friction48th pct · 1 measured

Open this in the hybrid builder

Which goes dead first?

Estimated from tension loss, which is the only thing the database measures about ageing. This is when the bed stops playing the way you strung it, not when the string breaks.

SpiralTek 17

~38 hours of play

Quasi-Gut Armor 17

~37 hours of play

Both strings in full

Every published measurement
StringGaugePriceStiff lb/inLoss %Power %SpinBite COFFriction COF
Babolat SpiralTek 17 Nylon17find14917935.60.4180.074
Tourna Quasi-Gut Armor 17 Nylon/Polyester17find14418935.60.5480.097

Add a third string SpiralTek 17 in full Quasi-Gut Armor 17 in full