The nomenclature and descriptions of both spin fishing and fly fishing equipment can be confusing and sometimes even misrepresentational. Before trying to translate your ultralight spin tackle experience into its fly rod counterpart, it's important to define exactly what ultralight spin tackle is.
Ultralight spin tackle could mean two things, depending on what you are fishing for and where. Ultralight spin tackle for bass generally falls into a category of rods that are 6-7' long and are in the 1-6 pound line weight and meant for efficiently casting smaller baits and lures in the 1/64 to 1/4 oz. weight. Much like fly rods, ultralight spin tackle can vary greatly and you could have a 3'6"-4' long rod for tiny trout streams or a 7' long 8 pound rod for bass and they are both still considered an ultra-light spin set up.
- The size and strength of ultralight spin tackle comes very close to that of a mid WT range fly rod. In fact, many ultralight spin anglers like to fish with nymphs or heavily weighted streamers.
- If you like ultralight spin tackle for bass fishing, then it's probably in the 6-8 pound range.
- 5-6 WT Fly Rods match the strength of a 6-8 pound spinning rod.
- You'll have the same issue you would with a fly rod that you do with the spin rod. Trying to cast larger lures that are heavier than your spin rod can handle is inefficient and messy. It's the same for a fly rod. Try to cast larger flies than your 5 or 6 WT rod can handle, and it gets to be pretty difficult.
- 2-3 WT fly rods are more meant for tiny trout streams, creeks, and brooks. An ultralight spin rod in the 1-4 pound range is closer to the strength of a 2 or 3 WT fly rod.
The Simple Answer
For the same experience as bass fishing with an ultralight spin rod, choose a fly rod that's in the 5-6 WT range. That's the best match to the same type of presentation and lure selection. Bigger bass can be tough to corral when using light rods, so it's a much tougher battle when you can't horse a big bass so it won't run into a log or under lily pads. The upside is that big bass on light tackle is a thrill; you just may lose a fish or two more than with a more equally matched rod.
If you want a wider range of possibilities in so far as fly selection when bass fishing, then you would be better suited to use a fly rod in the 6-8 WT range. This grants the ability to fish stronger leaders and to pull fish from structure and weeds.
