Almost every line commonly used for carp fishing has an under-rated breaking strain indicated on the spool or box. With a good knot, most line will always break at a higher strain.

With no international guidelines for indicating breaking strain or diameter, manufacturers under-rate lines to different degrees. A line labelled as 12lb from one Company may consistently break around 20lb; a line labelled as 12lb from a different Company may regularly break at just 14lb.

To give a better idea of the specifications of lines we sell we have tested breaking strains and diameters ourselves. We took line from different points on the spool and measured breaking strains five times using a Salter tension and compression tester, and diameters using a high quality digital caliper. Breakage tests were conducted with five turn grinner knots and a knotless knot to mimic what the average angler uses.

Braid diameters shown below are as accurate as possible, but unlike nylon lines some braids do not have round profiles. Each spool of line was tested brand new, but we accept that performance of all lines varies with age and different batches of lines supplied to shops may show slight differences in performance. However we hope the chart will provide useful general guidance.