Head to head

Genesis Black Magic 16 (1.29) vs IsoSpeed Black Fire 17

They split the measurements 3–3. The widest gap is ball bite, where Black Magic 16 (1.29) is 60 percentile points ahead. Every figure is a testing-machine result at a fixed reference tension.

Measured, side by side

Genesis

Black Magic 16 (1.29)

Polyester · 16 ga

IsoSpeed

Black Fire 17

Polyester · 17 ga

Stiffness lower = softer, kinder on the arm
20875th pct
20573rd pct
Tension loss lower = stays where you strung it
3660th pct
3966th pct
Energy return higher = livelier, more free power
8629th pct
8733rd pct
Spin potential higher = more spin off the string bed
6.282nd pct
5.671st pct
Ball bite higher = grabs the ball harder
0.49475th pct
0.38616th pct
String friction lower = strings slide and snap back
0.08024th pct
0.0694th pct

Bars are percentile against all 791 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 Black Magic 16 (1.29) at 52 lb

String Black Fire 17 at 52.7 lb 23.9 kg

Coming from Black Fire 17 at 52 lb

String Black Magic 16 (1.29) at 51.3 lb 23.3 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.

Black Magic 16 (1.29) mains / Black Fire 17 crosses

Stiffness74th pct · 1 measured
Tension loss63rd pct · 1 measured
Energy return30th pct · 1 measured
Spin potential80th pct · 1 measured
Ball bite69th pct · 1 measured
String friction18th pct · 1 measured

Black Fire 17 mains / Black Magic 16 (1.29) crosses

Stiffness74th pct · 1 measured
Tension loss64th pct · 1 measured
Energy return32nd pct · 1 measured
Spin potential74th pct · 1 measured
Ball bite25th pct · 1 measured
String friction6th 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.

Black Magic 16 (1.29)

~22 hours of play

Black Fire 17

~20 hours of play

Both strings in full

Every published measurement
StringGaugePriceStiff lb/inLoss %Power %SpinBite COFFriction COF
Genesis Black Magic 16 (1.29) Polyester16find20836866.20.4940.080
IsoSpeed Black Fire 17 Polyester17find20539875.60.3860.069

Add a third string Black Magic 16 (1.29) in full Black Fire 17 in full