Tips & Tactics #7 – What is all this X business?

Whoever came up with this diabolical method of classification was surely trying to keep the common man out of this sport. Like the secret password to get into a private club or the handshake that identifies you as a member, the X system of classifying tippet material is designed to be secretive. Members only!

But not to worry.  Here is the key to the lock; the code you need to get into the club:

The diameter added to the X factor will equal 11.

The diameter of 3X is  .008 inches. If you add the X factor of 3 to the diameter factor of 8 you get 11. What is the significance of 11? Damned if I know, but that’s how it goes.

4X – .007 or 7 + 4 = 11

5X – .006 or 6 + 5 = 11

6X – .005 or 5 + 6 = 11

I know, its nuts, but there you have it.

Why do you need to know the diameter? You don’t. You just need to know that a 5x is thinner than a 4x and that a 6x is thinner still. The thinner the material the less the fish is likely to detect it. The thicker the material the stronger it is likely to be.

You need to figure out the compromise between visibility (as well as delicacy of presentation) and strength that you are willing to gamble on. You will develop a feel for what size tippet is likely to be required given the type of fishing you are doing.

When “chucking and ducking” weighted offerings to Steelhead you may want a 1x or 2x leader (thicker and stronger) while a fussy Brown sipping spinners may require a 6x or 7x (thinner and less strong).

Also smaller flies will require smaller leaders just to get through the eye of the hook. Size 24 Adams on the San Juan will catch a 24 inch Brown but you need to figure out how to do it on a 6x tippet.

And remember – drag-free drifts no matter what tippet size!

(Read about my San Juan River adventures in Letters to Mack, Book One.)


For more information on the basics of fly fishing for trout go to How to Fly Fish for Trout, the FIRST Book to Read.

Tom's Fishing Stories

If you are enjoying these posts, please “like”, “share” and “retweet” them. Thanks for the support!