Line Weight and Rod Rating- Can I deviate?

I have a Cabela's Traditional II 9' 5wt rod, a White River 7'6" 5wt rod, a Cabela's RLS2 5wt reel and a White River 5wt reel and I am wondering if i can use a 4 weight line or maybe even a 3 weight line in these. Would there be any types of problems using a lighter line then the rod and reel are rated for?

This is because i dont have enough money to purchase any new rods or reels at the moment and I have realized that a 5wt line is a little heavy for the size of the fish that I catch around here.

No problem. Lots of folks line up or down a weight or two. You'll have to adjust your casting stroke accordingly for the lighter weight line.

The line weight has very little relationship to the size of the fish you are catching. Once the fly has been delivered it is not nearly as important as the tippet. While you can cast a lighter line with your rods it will not make the fish feel like they are bigger. Using a lighter line may help you make less splash when you deliver the fly but you will still be playing the fish with the same rod.

If you haven't bought your lines yet, get a 5 wt line for the reel that you want to put on the 9 foot rod, then try it on both rods and see if you like it or if you don't, then get a cheap 4 wt to try. You don't need a $60 line to have fun, try the lines from Hook and Hackle, they're very nice. Your 5 wt reels can work very well with the 4 wt lines.

because of how far out the fish have been I triedmy 4wt line on my 6wt rodand found it easier to keep control of more line out in the air overthe lake. could just be a head game too. I tend to do that a lot to myself.

Rainbowchaser has it right.

You fight the fish with the rod so going down in line weight will NOT make the fish "feel" any differently. BUT it will make it more difficult to make shorter casts. On casts shorter than about 45 ft (9 ft rod + 30 ft line + 9 ft leader) you will have underweighted the 5 wt rods with the lighter lines.

Beginners generally do better with heavier lines because they can feel the rod bend more easily. Unless you are a proficient caster, I think you will find the lighter line more difficult to cast. So I would not go out and buy a line.

From what you have said about your outfit being too heavy for the fish you are catching, this is what I would do. I would not go to a lighter line. I would actually go to a lighter rod and use the same line. Try to borrow a lighter rod such as a 4 wt and put your 5 wt line on it.

You can cast any line with any rod. The line numbers are based on the idea that this rod will load properly with 30 feet of this line out. Papagus demonstrates this by having enough #4 line out to make his #6 rod perform better for him. In that situation, the rod would be overloaded with a #6 line.

On the other hand, if you are doing a lot of short, under 30', casts on a small stream, line that #3 with a #4 line. The rod will load better and perform better for you.

This is why they make spare spools. :)

I've caught fish no longer than my little finger on flies big enough that it was hard to imagine how the little sucker managed to get a-hold of the thing. You are safe with a 5wt line.

There are some considerations underliing: WF lines are a problem false casting once you get the head out of the tip top. The running/shooting diameter line will not control the head and timing becomes critical to a fault because you have to be pulling the weight of the head at precisely the right time to load the rod. Add wind and you are toast assuming that you lined down to a 4wt or 3wt from 5wt, and much beyond a breeze will cause enough trouble with the 5wt line which isn't all that heavy itself. So if you want to underline and still have control on casts longer than 40' the DT and TT lines will be less frustrating, and of those two the TT would be the least trouble since the butt of that taper will always be heavier than the tip.

If you are not fishing far enough away to worry about getting the head of a WF line out of the tip top, then go with a longer/lighter compound leader not a lighter line. There are also furled leaders that act much like a triangle taper fly line and will help the leader act much like a very light fly line rolling out, and that will work fine with your 5wt

Much of the pleasure of fly fishing (for me at least) is the sensation of the rod working with the line while casting. When you under line your rod much of that enjoyable sensation is lost. The lighter the line the greater problem with wind spoiling your efforts in general and more so with underlining in particular.

Underlining is the kiss of death for a spey set-up.

What's a compound leader?

Compound leaders are made up of segments or "compounded" of pieces of different diameters to achieve a particular casting result. A tapered leader is an example of a "compound" leader, compounded of segments that are decreasing in diameter. If you make your own leaders you can control the decrease or increase in size of and length of the segments. You can thereby create different rates of turn over and various loop sizes etc. Here is a place to start into the wide world of leaders:
http://www.flyfishusa.com/tackle-tip...t-leaders.html

Google the topic and spend as much time as you wish surfing leaders. :-)