Polyfibre Cobra 17/1.20 vs Polyfibre Viper 17/1.20

Measured, side by side

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.

• More spin and shape

  Cobra 17/1.20605th

  Viper 17/1.20530th

• Easier on my arm

  Cobra 17/1.20319th

  Viper 17/1.20335th

• More control, less launch

  Cobra 17/1.20481st

  Viper 17/1.20469th

• More power and depth

  Cobra 17/1.20522nd

  Viper 17/1.20568th

• Plays the same for longer

  Cobra 17/1.20778th

  Viper 17/1.20783rd

• Lasts longer before it breaks

  Cobra 17/1.20550th

  Viper 17/1.20551st

• Best feel and touch

  Cobra 17/1.20520th

  Viper 17/1.20568th

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.

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.

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.

Both strings in full

Add a third string Cobra 17/1.20 in full Viper 17/1.20 in full