Berkley Vanish Leader Line vs. Mainline [Abrasion & Knot Strength Test Results]

By: Luke Simonds on August 6, 2018
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berkley vanish leader line and mainline

I’ve always wondered what the difference is between fluorocarbon leader line and fluorocarbon mainline and whether one would outperform the other on the water.

If the lines are the same material and the same pound test, shouldn’t they work the same on the water? I use Berkley Vanish leader line for most of my fishing rod setups and wondered whether I could get away with using Berkley Vanish mainline instead.

The Berkley Vanish leader line is about five times more expensive than fluorocarbon mainline that is the same pound strength, which can really add up if you’re buying lots of leader line all the time.

I decided to test these two Berkley Vanish line types against each other to see how they would hold up on the water.

To come to my conclusion, I tested the lines against each other using two criteria:

  1. Knot Strength
  2. Abrasion Resistance

For each test criteria, I tested 20 lb. Berkley Vanish leader line vs. 20 lb. mainline to see which line type performs better. I also tested 15 lb. Berkley Vanish leader line vs. 20 lb. mainline to see if the lighter leader line is stronger than the mainline.

berkley vanish leader lines and mainline

My guess was that the leader line would outperform the mainline because the leader line has a slightly thicker diameter than the mainline.

Note: Salt Strong is not sponsored by any fishing line manufacturers (this all is funded by the Salt Strong Fishing Club members), so there is absolutely no bias at all in these tests.

Our goal for these tests is to see which line is the most cost-effective and best-performing on the water.

Knot Strength: Berkley Vanish Leader Line vs. Mainline [Video]

For the first test, I decided to test the knot strength of Berkley Vanish leader line against the Berkley Vanish mainline.

The first test put the 20 lb mainline against the 20 lb leader line, and the leader line won all 3 tests.

But the leader is much thicker than the mainline, so I had to get some thinner leader line that had a more similar diameter to the mainline in order to determine if the line material was stronger or if the added diameter was the driving factor.

To do this, I tested Berkley Vanish lines of similar diameters — meaning I tested Berley Vanish 15 lb. leader line vs. Berkley Vanish 20 lb. mainline.

The diameter for each line is:

  • Berkley Vanish 15 lb. leader line — .38 mm
  • Berkley Vanish 20 lb. mainline — .40 mm

For the knot strength test, I tied the tag end of the mainline to a white swivel using a Non-Slip Loop Knot and connected the leader line and mainline using a Blood Knot. I then tied the tag end of the leader line to a black swivel using the Non-Slip Loop Knot.

You can see how I set up the test in the graphic below:

knot test berkley vanish leader line

I then attached the swivel to my scale and pulled at the connected lines to test which line broke first and what amount of force it took for it to break.

Whichever line the knot breaks on first is an indication of the weaker line.

Knot Strength Test Results

See the full knot strength test in the video below:

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I tested the knot strengths of these lines three different times with a similar result each time. My results were as follows:

  • Test 1 — the leader line loop knot broke first at just under 10 lbs. of pressure.
  • Test 2 — the leader line loop knot broke first at about 11 lbs. of pressure.
  • Test 3 — the leader line loop knot broke first at about 11.8 lbs. of pressure.

The results of this test showed that there is no benefit to Berkley Vanish leader line over Berkley Vanish mainline when the lines have a similar diameter.

Based on this knot strength test, the fluorocarbon main line is a cheaper option that performs just as well, if not better, than the leader line of a similar diameter.

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Abrasion Resistance: Berkley Vanish Leader Line vs. Mainline [Video]

For the abrasion resistance test, I made an oscillation device that simulates fishing line rubbing up against a piling or some kind of rough structure. The device works by rubbing coarse sandpaper back and forth on the two lines to see which line breaks first.

I attached the lines to two-pound weights which hung below the oscillation rod with the sandpaper — making the two lines taut over the sandpaper.

You can see the oscillation device in the graphic below:

berkley vanish leader line abrasion tests

Whichever line takes more oscillations before it breaks is the stronger line against abrasion. I decided to do two different kinds of abrasion tests:

  1. 20 lb. Berkley Vanish leader line vs. 20 lb. Berkley Vanish mainline
  2. 15 lb. Berkley Vanish leader line vs. 20 lb. Berkley Vanish mainline

Click here if you want to see our original test to see if leader line is more abrasion resistant than mainline.

Abrasion Resistance Test Results

See the full abrasion resistance test in the video below:

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For the first trial, I tested the 20 lb leader line vs the 20 lb. mainline. I tested the lines two different times and switched which side of the device the lines were on for each test. I then did the same using the 15 lb. leader line. My results were as follows:

 20 lb. Berkley Vanish Leader Line vs. 20 lb. Berkley Vanish Mainline

Line diameters:

  • 20 lb. Berkley Vanish leader line — .45 mm
  • 20 lb. Berkley Vanish mainline — .40 mm

Test results:

  • Test 1 — the Berkley Vanish mainline broke two oscillations before the Berkley Vanish leader line.
  • Test 2 — the Berkley Vanish mainline broke four oscillations before the Berkley Vanish leader line.

15 lb. Berkley Vanish Leader Line vs. 20 lb. Berkley Vanish Mainline

Line diameters:

  • 15 lb. Berkley Vanish leader line — .38 mm
  • 20 lb. Berkley Vanish mainline — .40 mm

Test results:

  • Test 1 — the Berkley Vanish leader line broke one oscillation before the Berkley Vanish mainline.
  • Test 2 — the Berkley Vanish leader line broke one oscillation before the Berkley Vanish mainline.

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Berkley Vanish leader line vs. mainline

The main takeaway I got from these tests is that there is not much difference between the Berkley Vanish leader line and the mainline.

The aspect that had the biggest effect on how strong the lines were for both tests had to do with how thick the diameter was. The thicker diameter lines were stronger in each test regardless of whether the lines were leader line or mainline.

So this proved that the mainline can be just as effective as a leader line as long as the mainline has the same/similar diameter as the leader line.

Berkley Vanish mainline is about five times less expensive per yard than the Berkley Vanish leader line, making it the obvious choice for me.

If you have any questions about these tests or have a suggestion about how to improve them, let us know in the comments below.

Tight lines!

Related Posts:

1. Is Fluorocarbon Leader Really Stronger Than Main Line? [Test Results]

2. Is Fluorocarbon Leader More Abrasion Resistant Than Traditional Mono Leader?

3. Berkley Vanish vs. Seaguar Blue Label Fluorocarbon Lines [Abrasion Test Results]

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Luke SimondsDavid JohnsonRandyMikeThomas Horsch Recent comment authors
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David Johnson

Thanks Luke!
A few questions.
Would results be the same for monofilament leader and mainline?
Is there a difference in sink rate/buoyancy between same diameter leader line and mainline?
Is there a difference in visibility between same diameter leader line and mainline of mono or flouro?
Thanks again
Tight lines
David Johnson


I’m landlocked in KY but I’ve been using Berkley Vanish mainline for leader material a long time. I use it for swimbait fishing. I came to know that it works so well because I ran out of leader line. I just grabbed the Vanish mainline. Haven’t bought leader line since. One of my swimbait combos is for medium swimbaits. You wouldn’t believe how hard I’ve pulled when snagged with 17lb Vanish. I was actually shocked. . Although I use 65lb braid and 17lb leader (backwards to saltwater) with Bloodknot connection. Think I’m gonna go with the FG knot a while. Your video sure made me feel good lol.


I meant Yo Zuri Topknot Leader vs Mainline in 20#


Can you test Yo zuri tooknot leader vs mainline in 20lb?

Thomas Horsch
Thomas Horsch

Love your site and YouTube videos for all the great fishing info. Wish I could find a similar source for freshwater fishing since I’m landlocked here in the middle of VA near Richmond. But still get a lot of good useable information from you for general fishing knowledge. Thanks again!

Teresa McCullough

I have been using Brekley Vanish Main Line for the past two years here in NC and love it but your test proves it even more. Thanks for proving it and now I know I did the right thing is switching to it. Great video and update.

Dave Otte

Luke, since we don’t have snook here in Pensacola, my leader has been 15 lb. Seaguar (.013″). I want to start using Vanish main line as my leader and save $$. Based on your results, would you use Vanish main line 20 lb (.016″) or 14 lb. (0.13″) for your leader?

This is awesome, you are creating extra value for us insiders! Thank you for your diligence!

Guy Leveille

My wallet loves the results of your comparison test! Not sure Berkeley is too happy though! Haha
Thanks again Luke!

James Woodmansee

Luke, thanks so much for conducting these tests. It looks like I will buy Vanish mainline in 25lb test (if they make it) to use as my “20lb” leader from now on.

James Woodmansee

Just went on Berkley web site and made three discoveries about the Vanish fluorocarbon mainline: 1) they don’t make 25lb test; 2)the smallest spool of 20lb test is 250yds which would be 375 leaders of 2ft lengths (at 72 y ears old and fishing once a week or week and a half I may not live long enough to use them all); 3) the reviews are not great…of 61 reviews 5stars=38 (62%), 4stars=3 (5%), 3 stars=1 (2%), 2 stars=7 (12%), and 1 star=12 (20%). That’s 32% of reviewers rating it 2 stars or less. I would recommend the next test be 5 most popular brands of fluorocarbon mainline (including Vanish) against each other for knot strength and abrasion resistance. Luke, how ’bout it?

James Woodmansee

PS: I typically take 2 rods in my kayak; the “regular” rod with 10lb braid and 20lb leader and the “snook” rod with 20lb braid and 40lb leader. That’s why the 250yd spool of 20lb test might outlive me (smile).

James Woodmansee

PPS: I just noticed the pics you posted in your tests show the 15lb leader material being .016 diameter and .38mm but the 20lb mainline material being the same .016 diameter but at .40mm. How can that be? The truth is that .016 inches = .4064mm.

James Woodmansee

and 0.38 Millimeters =
0.014960630 Inches

Edward Wygonik

Nice information. I mistakenly bought Vanish FC “mainline” when I first started fishing over a year ago. I then learned that this was really for spooling and not for leaders. I was planning on switching once I ran out… but honestly I still have 2/3 of the spool I use… I think I’ll buy one or two more… might last a lifetime 🙂

Gary Rankel

Good stuff, Luke…..the relationship between line thickness and abrasion resistance makes sense. Assuming the transparency of both fluoro types is the same, there seems to be no good reason to buy the leader any longer. I’d suggest you submit an article to one of the popular sport fishing magazines outlining your findings.

Nick Strickland

Excellent test! You’ll prob laugh,but for the past 15 yrs or so the leader I use most is 20lb pink Ande main line.I know it’s a soft line but I still dont lose fish because of it. I feel lures work better because of the softness and with circle hooks the leader is usually outside the mouth anyway.i also think pink is harder to see underwater.

Good work! I haven’t started a membership yet (because ive been fishing fla for over 60 yrs and think I know it all) lol. But some of your vids are pushing me to consider joining. Love your work and dedication!

Paul Williams

Nick, 60 years is a huge amount of experience. I have about 25+ years overall fishing fresh and saltwater and have landed several nice fish in my life, but I can tell you from personal experience, that after joining Salt Strong, my fishing game has improved dramatically. I rarely catch Cat’s anymore if at all, unless it is my wife, lol, and my slams and larger fish are being landed much more regularly, all in less time on the water. I am pretty skeptical when it comes to joining anything, but this was hands down the best money I have ever spent on anything fishing related. Salt Strong team does an awesome job and they keep bringing it. My only complaint is that the more I learn or watch, it makes me wish I was on the water every day, but some how or some way I have to pay for that lifestyle!

Nick Strickland

I agree. I never miss one of their articles…and honestly since living here I have been humbled. I struggle here (anclote) with bait,reds and flounder. Trout and snook no problem but the others are baffling me.
I’m sure I’ll join…just takes me a while to warm up to anything new lol…..hey I’m old lol
Thanks for your input!

Paul Williams

Nick, I hear ya, I was kind of in the same boat, I could catch trout, the occasional Snook, and tons of Flounder but Red eluded me. Since joining, I have landed more Reds, my largest 31″ and the Snook are off the hook. The fish that I am now catching less of is the Flounder, but mainly due to my spot selection now. When I pick more sandy areas with flowing water, I tend to land the Flounders more often. Flounder in Florida are tricky especially in the warmer months. My logs show they are moving in now and I am starting to catch more regularly over 14″ vs early summer I would only catch 10-12″ max.

Walt Byrd
Walt Byrd

Thanks Luke….
A little disappointed in Berkley; but thanks for the info …. that will save us all some change for other gear. 😊

Michael Teague

Good stuff. I would really love to see side by side knot strength tests as appose to tandem to see breakinh strength of each, but nice to know that two hundreths of a mm difference is insignificant in the water but bumps breaking strength by 5 lbs.


I have been using Vanish fluorocarbon mainline for years as leader material. I have never had any issue.

Nick Nemeth

Looks like diameter is the ultimate factor in all of these tests. Can’t wait to see the video for power pro max cuatro vs regular power pro of the same diameter.

Tommy Holmes

Great information. thanks for taking the time to make the comparison videos.

Nicholas George

Will you keep us posted on whether or not you see a difference in fish catching with said main line as leader?


Love those results Luke! Thank you for the post and all the time and hard work put into the testing.