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Kirschbaum

Pro Line I 17L (1.20)

Polyester Gauge 17L 1.21 mm In production

Lab measurements for Kirschbaum Pro Line I 17L (1.20), 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

195lb/in

lower = softer, kinder on the arm

Tension loss

52%

lower = stays where you strung it

Energy return

84%

higher = livelier, more free power

Spin potential

3.9

higher = more spin off the string bed

Ball bite

0.351COF

higher = grabs the ball harder

Snapback

0.089COF

lower = strings slide and snap back

How it ranks against all 789 strings

Stiffness 195 lb/in · 63rd pct

Stiffer than 63% of strings tested.

Tension loss 52 % · 92nd pct

Sheds more tension than 92% of strings tested — goes dead fast, expect frequent restringing.

Energy return 84 % · 12th pct

Livelier than 12% of strings tested.

Spin potential 3.9 · 27th pct

More spin potential than 27% of strings tested.

Ball bite 0.351 COF · 3rd pct

Grips the ball harder than 3% of strings tested — slick against the ball.

Snapback 0.089 COF · 44th pct

More string-on-string friction than 44% of strings tested.

Strings that play like this

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

Ashaway MonoGut 17 96% match Gamma Zo Tour 17 (1.25) 95% match Gosen Polylon PolyBreak 17 (1.24) 94% match Kirschbaum Pro Line I 17 (1.25) 94% match Gosen Polylon SP 16 (1.30) 94% match Prince Tour 17 93% 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 17L (1.20) against 789 strings Find the right string for me