StringSpec
String finder

Browse all 789

Kirschbaum

Pro Line I 18L (1.15)

Polyester Gauge 18L 1.15 mm In production

Lab measurements for Kirschbaum Pro Line I 18L (1.15), ranked against all 789 strings in the database. Every figure below is a testing-machine result at a fixed reference tension, not a playtest opinion.

Measured values

Stiffness

189lb/in

lower = softer, kinder on the arm

Tension loss

50%

lower = stays where you strung it

Energy return

85%

higher = livelier, more free power

Spin potential

4.4

higher = more spin off the string bed

Ball bite

0.377COF

higher = grabs the ball harder

Snapback

0.086COF

lower = strings slide and snap back

How it ranks against all 789 strings

Stiffness 189 lb/in · 57th pct

Stiffer than 57% of strings tested.

Tension loss 50 % · 89th pct

Sheds more tension than 89% of strings tested.

Energy return 85 % · 16th pct

Livelier than 16% of strings tested.

Spin potential 4.4 · 40th pct

More spin potential than 40% of strings tested.

Ball bite 0.377 COF · 11th pct

Grips the ball harder than 11% of strings tested.

Snapback 0.086 COF · 36th pct

More string-on-string friction than 36% of strings tested.

Strings that play like this

Closest matches across stiffness, tension loss, energy return and spin potential.

Alien Black Diamond 16 96% match Gosen Polylon PolyBreak 17 (1.24) 95% match MSV Co.-Focus 16L 95% match Gosen Polymaster I 16 95% match Klip Hardcore 16/1.30 94% match Gosen Polylon SP 16 (1.30) 94% match

More from Kirschbaum

What these numbers mean

Stiffness · lb/in

How much the string bed resists deflection. Higher plays firmer and more controlled; lower plays softer and easier on the arm.

Tension loss · %

Share of the reference tension the string sheds under a fixed test protocol. Lower means the bed stays where you strung it for longer.

Energy return · %

Share of impact energy handed back to the ball. Higher plays livelier and more powerful.

Spin potential

Ball friction divided by string-on-string friction. Higher means better bite with a cleaner snapback, so more spin.

Ball bite · COF

String-on-ball friction. Higher grabs the ball harder through the brush.

Snapback · COF

String-on-string friction. Lower lets the mains slide and snap back into place after impact.

Compare Pro Line I 18L (1.15) against 789 strings Find the right string for me