Head to head

Kirschbaum Helix 17 vs Signum Pro Poly-Plasma Pure 16L

They split the measurements 3–3. The widest gap is ball bite, where Poly-Plasma Pure 16L is 32 percentile points ahead. Every figure is a testing-machine result at a fixed reference tension.

Measured, side by side

Kirschbaum

Helix 17

Polyester · 17 ga

Signum Pro

Poly-Plasma Pure 16L

Polyester · 16L ga

Stiffness lower = softer, kinder on the arm
20977th pct
22188th pct
Tension loss lower = stays where you strung it
4474th pct
4168th pct
Energy return higher = livelier, more free power
8627th pct
8625th pct
Spin potential higher = more spin off the string bed
5.467th pct
5.671st pct
Ball bite higher = grabs the ball harder
0.41433rd pct
0.46765th pct
String friction lower = strings slide and snap back
0.07615th pct
0.08330th 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 Helix 17 at 52 lb

String Poly-Plasma Pure 16L at 46.4 lb 21.0 kg

Coming from Poly-Plasma Pure 16L at 52 lb

String Helix 17 at 56.9 lb 25.8 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.

Helix 17 mains / Poly-Plasma Pure 16L crosses

Stiffness82nd pct · 1 measured
Tension loss72nd pct · 1 measured
Energy return26th pct · 1 measured
Spin potential68th pct · 1 measured
Ball bite39th pct · 1 measured
String friction18th pct · 1 measured

Poly-Plasma Pure 16L mains / Helix 17 crosses

Stiffness84th pct · 1 measured
Tension loss70th pct · 1 measured
Energy return26th pct · 1 measured
Spin potential70th pct · 1 measured
Ball bite61st pct · 1 measured
String friction27th 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.

Helix 17

~18 hours of play

Poly-Plasma Pure 16L

~20 hours of play

Both strings in full

Every published measurement
StringGaugePriceStiff lb/inLoss %Power %SpinBite COFFriction COF
Kirschbaum Helix 17 Polyester17find20944865.40.4140.076
Signum Pro Poly-Plasma Pure 16L Polyester16Lfind22141865.60.4670.083

Add a third string Helix 17 in full Poly-Plasma Pure 16L in full