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What it is
Leadcore and trolling lines are specialty lines built to do one job: sink your lures deep behind the boat without downriggers, divers, or heavy bottom weights. The most common is lead-core line — a soft lead wire wrapped inside a braided Dacron or nylon sheath. That lead center makes the line heavy, so the more you let out, the deeper your lure runs. It is purely a trolling tool, fished on trolling reels and trolling rods and used only for trolling.
Lead-core’s signature feature is that it is color-coded, changing color every 10 yards. Each 10-yard segment is called a “color,” and you count colors as you let line out to estimate — and then repeat — your depth. A rough rule of thumb is several feet of depth per color at normal trolling speed, but that number shifts with boat speed, lure size, and how much line is out, so treat it as a starting point and confirm with your own results. Because the line is thick and visible, you finish it with a long mono or fluoro leader to the lure.
When to reach for it
Reach for leadcore when you want to fish a specific mid-depth zone and you do not have downriggers, or you want a simpler, cheaper way to get down. It shines on open water for suspended fish — this is classic Great Lakes gear for walleye, salmon, and lake trout, where running lures at a repeatable depth is half the battle. If you mark fish at 25 feet, you let out enough colors to put your lure there, then duplicate it on the next rod.
For water deeper than leadcore comfortably reaches, anglers step up to copper line, which sinks faster and deeper for its diameter — great for very deep presentations, though it takes longer rods and bigger reels to handle. Weighted or lead-impregnated trolling lines are close cousins, adding sink without the bulk of full leadcore.
How to choose
Pick your line by breaking strength and rig it on a line-counter reel so you can measure exactly what you let out. For most walleye and salmon work, 18 lb leadcore is the do-everything choice — enough sink without excessive bulk. Lighter 12 lb runs a little deeper per color; heavier 27 lb handles big lake trout lures.
Back the leadcore with mono or braid on the reel spool — a few hundred yards of 20-30 lb backing is plenty — and tie a long leader off the front. Run 10 to 30 feet of mono or fluorocarbon, with fluoro preferred in clear water for its low visibility. Connect leadcore to leader and backing with back-to-back uni knots or loop-to-loop connections so the joints pass cleanly through the guides. For a full primer on how leadcore fits alongside braid, mono, and fluoro, see the line overview.
A practical starting setup: one full spool of 18 lb leadcore (10 colors, 100 yards) behind 20 lb backing, finished with a 15-foot fluoro leader, on a line-counter trolling reel.
Brands worth knowing
Sufix 832 Advanced Lead Core — a tight, abrasion-resistant braided sheath that holds its color coding well and trolls smoothly. The go-to for serious Great Lakes trollers. Mid to premium price tier.
Cortland Lead Core — a long-trusted, dependable workhorse leadcore at a fair price. A solid first spool if you are just adding leadcore rods to the spread. Budget to mid tier.
Mason Leadcore — a no-frills, consistent leadcore that many veteran walleye and salmon anglers have run for years. Reliable color marking and easy to handle. Budget to mid tier.