So…I’ve been told many times that casting a large fly rod, like my 8 wt, is considerably different than casting a small trout rod. Not knowing the difference, I thought, “Sure…ok…can’t be that hard.” I had only ever cast an 8 wt until this spring. I bought anew trout rod so I’ve been casting a 7.5 ft 5 wt all spring and have had no time to practice with the 8wt salmon rod. I get 2 hrs to try and hook a salmon, step out onto the bank, string up the 8 wt and proceed to cast like I have a wet noodle on the end of a broomstick. It was both frustrating and embarrassing at the same time and I caught nothing except trees. The moral of the story is if anyone gives you advice, at least try it before you dismiss it. If I had taken a 1/2 hour to do some lawn casting before I went (as I had been told many times to do) I would have had a much more enjoyable time on the river. Yield to experience…it will usually yield good results
Hi Brad,
Just remember that ANY new rod can take some getting use to. Don’t give up on the eight weight just because it was different. A little change in your timing and you will be throwing some real distance with ease. There is nothing inherently evil about a heavier rod; it’s just different and takes some adjustment on your part. The same thing would have happened if you had started with the eight weight first and then switched to a five weight—it wouldn’t have felt right. Hang in there. 8T 
I enjoy casting rods of different speeds and seeing how long it takes me to fish them. I have always fished a realatively fast rod. I had a slow action rod that I bought for one of my kids and fished with it all day and it was fun to try a different action in that I really had to wait on the cast to develop before I rushed it. I fish 4 to 8wts on a reg basis. What I think that many speak to, is the great difference between casting your salmon rod or an 8 wt and a saltwater 12 wt. I think that difference would be much more drastic than me changing from my 4 to one of the 7s or the 8 wt rod.
I sure wish that I lived next to the salt to give it a go though. Maybe one day will try it out. I fish the 4 wt on small spring creeks for trout and the two 7s and the 8 are for my steelhead/salmon/carp outfits. By the way carp are my favorite and if you haven’t tried them, that is one sure fire way to have fun and develop your skill with a little heavier rod than the small spring creek rods and the opportunities are usually close to home.
Rick
It happened to me when but more of the opposite. Casting and fishing a 9ft 8wt graphite and then immediately switching to a 7’ 5wt glass rod…it was very disorienting but after a bit it made sense.
Anytime you change rod weight, rod action, lines etc, there is going to be an adjustment period where things are just not going to feel right and your casting is going to “off” for a while. Even fly changes can mess up a caster, particularly a newbie caster, for some period of time. Watch someone who is use to dry flies trying to cast a heavily weighted nymph or a Clouser Deep Minnow. It all requites changes in timing, power and stroke. Experienced casters (like our Uncle Sam) adjust quickly so that you hardly notice, the rest of us… 8T
The good thing that happens with learning on a heavier rod is that you build up hand and arm strength and its easier for a beginner to “feel” the timing better.
After “working out” with a 12 wt (false casting while carrying a lot of line and extending it everyday) til my hand got tired, I could cast a 8wt or a 6wt all day in any conditions. The loop control and timing has helped me greatly in my short range accuracy and im ok blind casting clousers in saltwater with shooting heads.
The lessons learned help with adjusting to different rods or more importantly they help to select a rod to fit your particular style —always try it before you buy it!
The good thing is that you will recognize a rod that doesnt work for you and you wont waste your money adding it to your closet collection.
When I am on the river in a drift boat I have three rods rigged and ready to go.
My nymphing rig is a fast action 11 foot Sage XP 6 wt and or my 11 foot Sage Z-Axis 6 wt.
My dry fly rig is a true medium action Sage rod, the 9 foot, 5 weight VPS Light.
For streamers I have one of several Sage 9 foot 6 weight medium action rods that I will bring along on the trip.
Anytime I switch from one rod to the other I have to take a moment and think, "This is the ‘… rod’ and cast accordingly. When I don’t take that moment and try to cast my medium action rod like I do my fast action rod, the cast is horrible. That reminds me to take a moment and think.
Oh yea, by the way, I like Sage rods.
Larry 
—sagefisher—
This brings up an important point. So many times I hear guys talking about selecting a rod that fits your style and casting it first. While I agree that one should know what you are getting into, I think that we should be able to cast any thing with some skill. I definately have a preference for faster rods for the majority of my fishing but stepping out of my routine, I find helpful in keeping that flexible skill set.
I fish many St. Croix rods. The 3 Legend Elites are fast, the Legend Ultra is slower and the Avids seem slower yet. I can fish and do fish them all in a single weekend.