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Head to head

IsoSpeed Professional Classic 17 vs Wilson Hollow Core Pro 16

They split the measurements 3–3. The widest gap is ball bite, where Hollow Core Pro 16 is 34 percentile points ahead. Every figure is a testing-machine result at a fixed reference tension.

Measured, side by side

IsoSpeed

Professional Classic 17

Polyolefin · 17 ga

Wilson

Hollow Core Pro 16

Nylon · 16 ga

Stiffness lower = softer, kinder on the arm
1344th pct
14710th pct
Tension loss lower = stays where you strung it
2946th pct
3251st pct
Energy return higher = livelier, more free power
9168th pct
9165th pct
Spin potential higher = more spin off the string bed
1.61st pct
2.23rd pct
Ball bite higher = grabs the ball harder
0.3211st pct
0.41735th pct
String friction lower = strings slide and snap back
0.20798th pct
0.19097th 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 Professional Classic 17 at 52 lb

String Hollow Core Pro 16 at 46.4 lb 21.0 kg

Coming from Hollow Core Pro 16 at 52 lb

String Professional Classic 17 at 70.0 lb 31.8 kg

Clamped. The proportional answer was 714.4 lb, outside what most frames are rated for.

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.

Professional Classic 17 mains / Hollow Core Pro 16 crosses

Stiffness5th pct · 1 measured
Tension loss48th pct · 1 measured
Energy return66th pct · 1 measured
Spin potential1st pct · 1 measured
Ball bite2nd pct · 1 measured
String friction98th pct · 1 measured

Hollow Core Pro 16 mains / Professional Classic 17 crosses

Stiffness6th pct · 1 measured
Tension loss49th pct · 1 measured
Energy return66th pct · 1 measured
Spin potential2nd pct · 1 measured
Ball bite25th pct · 1 measured
String friction98th 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.

Professional Classic 17

~26 hours of play

Hollow Core Pro 16

~25 hours of play

Both strings in full

Every published measurement
StringGaugePriceStiff lb/inLoss %Power %SpinBite COFFriction COF
IsoSpeed Professional Classic 17 Polyolefin17find13429911.60.3210.207
Wilson Hollow Core Pro 16 Nylon16find14732912.20.4170.190

Add a third string Professional Classic 17 in full Hollow Core Pro 16 in full