Using a 4 Wt line on a rod designed for 5 wt

[mcneishm]

I have nearly always 8.5" bought rods that used a 5 or 6 wt line, mostly 5 wt. I was recently given a reel that already had a 4 wt line on it. Can anyone provide what the possible effects of using a 4 wt on a rod designed for 5 wt?

 

[TimMurphy]

Dear mcneishm,

The effects will be minimal unless the rod is an older extremely slow action rod, or a newer extremely fast action rod.

Dropping down a line size generally has the effect of making the rod seem a little faster. This is due to the fact that the lighter line doesn't load the rod as much until you get 40 or 50 feet of the line in the air.

Lefty Kreh often recommended using a size lighter line to combat windy conditions. Having done that I tend to agree with him.

I can tell you that if you practice a bit you'll probably find that most of the fly rods you use are capable of casting a size lighter or a size heavier line than they are rated without too many ill effects.

Try your new reel and line in your yard, if you feel like it works there it will also work on the stream.

Regards,

Tim Murphy

 

[Swattie87]

Yep...in general you will need more 4wt line out to "load" the rod to the same degree than you would with the heavier 5wt line. For making long distance casts "underlining" the rod like this may actually be beneficial for this reason...you're hitting the sweet spot in terms of load on the rod with more line out. On the other hand, for shorter casts you may find it a little more difficult to load the rod with the lighter line. Depends on what kind of fishing you're going to do. I generally overline my small stream (short cast) rods, and fish my other rods at their rating. That said I would definitely consider underlining a rod if I was anticipating making repeated long (40-50ft + casts) that day...I just don't fish in those circumstances very much.

In the end, I agree with Tim though...for most rods with just some mild casting stroke adjustments you can probably fish +/- a line size without too much difficulty.

 

[mcneishm]

Since I'm primarily a nymph fisherman and seldom do 40-50 foot casts, it looks like the 4 wt. might present some problems. I'm going to give it a shot nonetheless. The reel is nice - Orvis Clearwater - better quality than I would ever have bought for myself. If the line doesn't do well on my 8.5' Sage, I'll put a 5 wt. on the reel and find someone who wants the 4 wt.

 

[pcray1231]

It's not optimal, but I'm betting you'll find that the difference isn't all that much.