What is Stroft GTM tippet?
Stroft GTM is a monofilament tippet or leader material made from polyamide alloy and has a near transparent clear-blue-grey colour. According to Stroft, it's "the most successful fishing line worldwide" and is both strong and soft - hence the name "Stroft". In fact, it seems to be particularly strong for its diameter and feels much more supple than some other tippet materials, so it can be a particularly good choice in certain fly fishing situations.
The GTM part of its name comes from the German phrase "Getempertes Monofil" which means "tempered monofilament". Basically, it undergoes a really clever heat treatment process, along with some similarly complicated chemistry stuff. Stroft's boffins say this has helped it improve breaking strain, hardness, smoothness, elastic limit, stretchiness, feedback, memory and softness, among other things.
What breaking strains are available?
Like a lot of other specialist tippet materials, Stroft is sold more on the diameter rather than the breaking strain. This is because you're really supposed to match the diameter of the line to the size of your fly to achieve the best turnover. There are a massive range of lines available from the smallest at 0.25kg (0.55 lbs) which has a diameter of 0.030 mm, right up to 28 kg (61.7 lbs) which has a 0.60 mm diameter.
Obviously, I can't test any fishing line claims as I neither have the expensive machinery required nor the physics knowledge to interpret the results, but other independent tests have found this to be a very high performing line - the best in the test, in fact. It's also one of the few tippet materials I've seen which has the European Fishing Tackle Trade Association (EFTTA) logo on it which apparently proves it's been tested to its claims.
Stroft doesn't use the X rating system so it's a little complicated to directly compare it to other lines, so I've estimated the X rating myself below to give you a rough idea of how it compares to your current line of choice.
Obviously this is comparing apples to oranges, but compared to popular premium fluorocarbon tippet materials such as Fulling Mill Masterclass and Airflo Sightfree G5, Stroft GTM seems to be a bit thinner and a bit stronger in most sizes.
As a randomly picked example, Fulling Mill Masterclass 3X has a 0.196mm diameter and a 3.23 kg / 7.12 lb breaking strain; Airflo Sightfree 3X has a 0.203mm diameter and a 3.81 kg / 8.4 lb breaking strain, while Stroft GTM in approximately 3X has a 0.200mm diameter and a 4.22 kg / 9.26 lb breaking strain.
|Diameter||Breaking strain||Approx. X rating|
|0.030 mm / 0.0012"||0.25 kg / 0.55 lb||9.8 X|
|0.040 mm / 0.0016"||0.35 kg / 0.77 lb||9.4 X|
|0.050 mm / 0.0020"||0.50 kg / 1.10 lb||9.0 X|
|0.060 mm / 0.0024"||0.65 kg / 1.43 lb||8.6 X|
|0.070 mm / 0.0028"||0.80 kg / 1.76 lb||8.2 X|
|0.080 mm / 0.0031"||0.95 kg / 2.09 lb||7.9 X|
|0.090 mm / 0.0035"||1.20 kg / 2.65 lb||7.5 X|
|0.100 mm / 0.0039"||1.40 kg / 3.09 lb||7.1 X|
|0.110 mm / 0.0043"||1.60 kg / 3.53 lb||6.7 X|
|0.120 mm / 0.0047"||1.80 kg / 3.97 lb||6.3 X|
|0.130 mm / 0.0051"||2.00 kg / 4.41 lb||5.9 X|
|0.140 mm / 0.0055"||2.30 kg / 5.07 lb||5.5 X|
|0.150 mm / 0.0059"||2.60 kg / 5.73 lb||5.1 X|
|0.160 mm / 0.0063"||3.00 kg / 6.61 lb||4.7 X|
|0.170 mm / 0.0067"||3.30 kg / 7.28 lb||4.3 X|
|0.180 mm / 0.0071"||3.60 kg / 7.94 lb||3.9 X|
|0.190 mm / 0.0075"||3.90 kg / 8.60 lb||3.5 X|
|0.200 mm / 0.0079"||4.20 kg / 9.26 lb||3.1 X|
|0.210 mm / 0.0083"||4.60 kg / 10.14 lb||2.7 X|
|0.220 mm / 0.0087"||5.10 kg / 11.24 lb||2.3 X|
|0.230 mm / 0.0091"||5.40 kg / 11.90 lb||1.9 X|
|0.240 mm / 0.0094"||5.80 kg / 12.79 lb||1.6 X|
|0.250 mm / 0.0098"||6.40 kg / 14.1 lb||1.2 X|
|0.260 mm / 0.0102"||6.70 kg / 14.77 lb||0.8 X|
|0.270 mm / 0.0106"||7.00 kg / 15.43 lb||0.4 X|
|0.280 mm / 0.0110"||7.30 kg / 16.09 lb||0.0 X|
|0.290 mm / 0.0114"||7.70 kg / 16.9 lb||-0.4 X|
|0.300 mm / 0.0118"||8.10 kg / 17.86 lb||-0.8 X|
|0.325 mm / 0.0128"||9.30 kg / 20.5 lb||-1.8 X|
|0.350 mm / 0.0138"||10.5 kg / 23.15 lb||-2.8 X|
|0.375 mm / 0.0148"||12.2 kg / 26.90 lb||-3.8 X|
|0.400 mm / 0.0157"||14.0 kg / 30.86 lb||-4.7 X|
|0.425 mm / 0.0167"||15.7 kg / 34.61 lb||-5.7 X|
|0.450 mm / 0.0177"||17.5 kg / 38.58 lb||-6.7 X|
|0.475 mm / 0.0187"||19.2 kg / 42.33 lb||-7.7 X|
|0.500 mm / 0.0197"||21.0 kg / 46.30 lb||-8.7 X|
|0.525 mm / 0.0207"||22.7 kg / 50.04 lb||-9.7 X|
|0.550 mm / 0.0217"||24.5 kg / 54.01 lb||-10.7 X|
|0.575 mm / 0.0226"||26.2 kg / 57.76 lb||-11.6 X|
|0.600 mm / 0.0236"||28.00 kg / 61.73 lb||-12.6 X|
What are the spools like?
Stroft spools are available in several capacities. I'm using the 25m ones, which are smaller than most others on the market but are actually quite a practical way to buy tippet if you use lots of different diameters. However, the most commonly sold sizes are the standard 50m ones and the larger 100m spools. Stroft makes these with and without a built-in tippet cutter, but you tend to see only the regular spools on sale commonly in the UK, probably because they're a little cheaper to buy. As Stroft GTM is also used as a fishing line, massive bulk spools are also available, though they're not really ideal to stick in your vest pocket.
Do the spools come with bands?
Yes, but rather than the usual rubber band or elasticated strap, Stroft instead uses a very soft ring of expanded foam. This actually works quite well and stops the line unravelling from the spool too easily, so you shouldn't waste too much tippet if the spools are attached to your lanyard or spool tender. The minor downside is that it can be a bit of a challenge to find the end of the tippet beneath the foam if you inadvertently lose the end.
What is Stroft GTM like to use?
This stuff is strong and soft and much thinner than I thought it would be based on the breaking strain, so if you specifically want tippet of a certain diameter to aid fly turnover or minimise dropper tangling, then I'd definitely recommend you choose on the diameter rather than the breaking strain.
I've been using a number of different breaking strains and all of them performed very well. With a grinner or uni knot and a bit of salivary lubrication knots pull down tightly and neatly and there's no pig-tailing. Water knots and double surgeons' knots work well on droppers and hold well.
All of the lines I tested were very strong and I experienced no breakages or snap-offs. The softness of the line also lets your flies present very naturally, especially on droppers, so I can really see why this line is so popular. Like any mono, it doesn't sink as well as fluorocarbon so does need a bit of degreasing with mud if you're fishing dries.
How much is Stroft GTM tippet?
Stroft GTM is actually surprisingly good value and not as expensive as I thought it would be. The 100m spools are by far the best value for money. You can pick up the 50m spools in the UK for around £4.49, but the 100m spools are available for only £5.99, so you get twice as much for only a fraction more. That makes this a really good value line, especially given the quality. I found it thin, strong, supple and reliable and think you'd struggle to find a better value tippet material for the money.
More information: WAKU GmbH