Most tents available today are made of synthetic lightweight fabrics like nylon or polyester.
The difference between 10D through 40D nylon fabrics is the thickness of the thread used in the tent sheet fabric. Whereas 10D nylon threads only weigh 1.1g/Km, 40D nylon is four times heavier at 4.4g/Km.
Nylon is the superior fabric when compared to polyester as it is lighter and stronger for the same weight. However, polyester also has its advantages for tents, which you can read more about in my post comparing nylon and polyester for tents.
Due to the lightweight and strength of nylon, most modern lightweight tents are made using nylon fabric for the flysheet, inner tent, and bottom.
Whereas the outer layer, or flysheet, is often made from the materials that I am going to write about in this post, the floor/bottom of a lightweight tent is often also made from even thicker nylons or polyester versions e.g. 70D or 100D.Material Grams/1000m
threadAvg. Fabric density Water resistance
(Hydrostatic Head)7D Nylon 0.8 19 g/m² 1000-2000mm 10D Nylon 1.1 25 g/m² 1000-2000mm 15D Nylon 1.7 30 g/m² 2000mm 20D Nylon 2.2 34 g/m² 3000-4000mm 30D Nylon 3.3 47 g/m² 4000-5000mm 40D Nylon 4.4 54 g/m² 5000mmm 210D Nylon 23.3 70 g/m² >15000mm
The thinnest nylon material is 7D nylon, which is extremely light at 19 grams per square meter for tent sheet fabric.
The diameter of 7D thread is around the same as that of silk!
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So what exactly is nylon?
Nylon is a synthetic fabric made from the chemical extrusion of polyamides.
The initial idea was to make a soft but strong material, which succeeded quite well. In fact, it was originally made as an alternative to silk fabric for clothing!
What is Nylon and Polyester?
However, today it is commonly used for clothing, ropes, tents, sleeping bags, and also for parachutes and hot air balloons due to its lightweight and high strength!
The thicker nylons such as 210D, 420D, 600D, and up to 1680D are extremely strong and durable and are therefore used in backpacks and durable outdoor clothing.
Compared to polyester, nylon is more stretchable and lighter for the same strength. Depending on the coating, it is as waterproof and abrasive resistant, but also more expensive.
Polyester, on the other hand, is more heat and UV resistant and does not expand when wet.
Most modern nylons are made with the so-called rip-stop technique, which means that strong threads (thicker than the main material) are woven into the fabric at regular intervals.
Nylon is the material of choice for weight-critical products such as ultra-light camping tents. This is because it can be made down to ultrafine threads that allow for the very thin fabric to be made.
However, if you are ultra serious about weight and strength, you should check out the Dyneema (cuben fiber) material!
What is 10D Nylon?
10D nylon, next after 7D nylon is the thinnest nylon material that can be made for reasonable use in tents. It is extremely thin, quite transparent to light but also very lightweight – weighing less than half that of a typical 20D nylon material.
The D in nylon designations stands for “denier”. And Denier is the number of grams that 9000 meters of the fabric thread weigh.
This means that the 10D nylon is woven from a thread that weighs 1.1g per 1000m in length.
What is 10D ripstop nylon?
Rip-stop is a method used when weaving the 10D nylon fabric that ensures that any tears of the thin main fabric do not propagate along and end up tearing the whole sheet apart.
Ripstop is done by integrating thicker threads e.g. of 30D nylon into the thinner 10D material.
These tinner nylon materials are often used for ultralight sleeping bags and down jackets because they are also softer in feel and durability is not as high a priority as e.g. for tents.
The 10D nylon Outdoor Vitals Down TopQuilt
Is 10D Nylon durable?
Being thin and light, 10D nylon is naturally not the most durable material out there. However, I own a tent with a flysheet of 10D ripstop nylon, and it has survived numerous camping trips so far.
It even tolerates the placement of heavy (and sometimes sharp) rocks in the corners of the tent to stabilize under hard wind conditions!
How waterproof is 10D nylon?
10D nylon is usually rated at 1000-2000mm hydrostatic head pressure tolerance. The exact number depends on the coatings, and some brands treat their fabric with both PU and SI coatings can achieve even higher, but at the expense of weight and functionality.
Tens made from 10D nylon
A good example of a tent using 10D nylon in its flysheet is the newest version of the Naturehike Cloud Up tent 10D.
This is a very lightweight tent at less than 1 kg (2 lbs) for a 2-person tent. It also comes in a 20D (3.9lbs) version and a 210T polyester (4.6lbs) version.
The Cloud Up 10D is an affordable and very lightweight 2-person tent.
If you’re curious about the top ultralight but affordable tents out there, check out my comprehensive list of 20 lightweight budget tents.
What is 15D Nylon?
15D nylon thread weighs 1.7 grams per 1000 meters and is, therefore, thicker than 10D nylon, but thinner than 20D nylon.
If woven to the same distance between threads, the fabric of 15D nylon will not be much heavier compared to 10D though, as less thread is needed to make the same amount of fabric. In fact, 15D is only around 5 grams heavier per square meter compared to 10D.
15D nylon durability
The 15D fabric is quite a lot more durable than 10D or 7D nylon and is therefore used for more products like tents and sleeping bags.
It is waterproof to around 2000mm, which is good for moderate overnight rain showers, and can be treated with PU or silicone to become even more waterproof.
15D nylon tents
For example, 15D nylon is used in more and more ultralight tents like the Big Agnes Copper Spur HV UL, the Naturehike Mongar, the Naturehike Cloud Peak, or the Lanshan Ultralight Tent from 3F UL Gear.
These are all great tents for the weight-conscious hiker on a budget. See my full list of ultralight tents here.
You can also read my full review of the Naturehike Mongar 2 tent in this post.
What is 20D Nylon?
20D nylon is a good all-around lightweight nylon fabric used for most of the lightweight backpacking tents available out there.
20D nylon weighs 2.2 grams per 1000m of thread, which is twice that of 10D nylon, but will also provide the fabric with (more than) twice the strength.
It is a very versatile fabric with a perfect balance between, weight cost and durability, which is why it is still the preferred fabric of choice for lightweight tents.
For examples of tents made with this fabric, see the majority of the tents on my 20 favorite lightweight budget tents.
The Cloud Up 20D is one of my favorite 20D tents.
10D vs. 20D nylon for tents
The difference is the thickness of the thread used to weave the two fabrics. The thread used for 20D weighs 2.2g per 1000 meters whereas the thread used for 10D nylon only weighs 1.1 g per 1000 meters.
This makes the 20D thread almost twice as heavy as 10D nylon, but also more than twice as strong! However, the woven 20D nylon fabric is not twice as heavy as the 10D fabric. In fact, it is only around 10 grams heavier.
Whereas 10D is often too fragile to be used for all-season tents, 20D is used for both flysheets and floors by many ultra-light tent manufacturers.
Whereas 10D nylon is (depending on coating) waterproof to around 1000mm hydrostatic head, the 20D is usually rated at 3000-4000mm water resistance, which is useful for even the heaviest rain. The 1000mm of 10D nylon is mostly useful for lighter rainfalls and not suitable for floor material in tents.
15D vs. 20D Nylon
There is not a huge difference between 15D and 20D nylon. Although it comes down to 0.5 grams per 1000 meters of thread used to make the fabric, that is roughly 5 grams heavier per square meter – so using 15D or 20D does not mean a lot for the final product!
For example, the Naturehike 2 person Cloud Peak tent weighs 2.2kgs in the 15D version and 2.4kgs with 20D nylon. This is a fairly minimal difference, but if weight is a high priority it is perhaps worth going for the 15D material.
When it comes to water resistance, most tents made from 20D nylon have a waterproof rating of 3000-4000mm, whereas the 15D tents are closer to 2000mm in their hydrostatic head tolerance.
Some brands treat their 15D fabric with both PU and SI coatings can achieve higher water resistance on par with 20D nylon but at the expense of weight and functionality.
Do you know the difference between nylon and polyester and that polyester is widely used for rain gear, sleeping bags, tents, and sleeping pads? And do you know how it impacts the functionality? Other materials like that of the extremely durable and waterproof Dyneema material are also used more and more in outdoor gear.
I wrote an article about the impact of the material on rain gear, on tents, and a post on sleeping pads or whether nylon backpacks are waterproof.
What is 30D Nylon?
30D nylon weighs 3.3 grams per 1000m of thread and is therefore in the heavy end for lightweight tents, but perfect for ultralight backpacks or tents in the high durability end of the spectrum.
It is, however, quite rare to see it in tents as tents with high durability requirements will rather use the cheaper and stronger polyester fabric (E.g. 210T polyester) because the weight is no longer as important.
Some ultralight tents do use the 30D nylon for floor material as it is a good material for an ultra-light fairly sturdy groundsheet. Usually, such a sheet would be treated with a PU (polyurethane) to make it sufficiently waterproof and durable as a tent groundsheet.
30D nylon is usually rated to around 5000mm with the right coating, which is sufficient for a four-season tent and most groundsheets.
20D vs. 30D rip stop nylon
30D is approximately one-third heavier than 20D nylon but almost twice as strong in most cases, so deciding which one to use will depend on your need for durability vs. weight.
20D nylon can be made quite durable using the ripstop technique and very waterproof with the right coatings (3000-4000mm). 30D is stronger and waterproof to 5000mm of hydrostatic head.
20D is by far the most popular fabric for tents because it weighs less than 30D, and in most cases, the extra strength of 30D nylon is not needed for tents.
However, for groundsheets, the 30D is often used instead of 20D and few manufacturers go lower than 20D for their groundsheets.
What is 40D Nylon?
40D nylon is a synthetic fabric woven with thread that weighs 4.4 grams per 1000m of length. This fabric is rarely used for tents as polyester is the more obvious choice if this kind of strength is needed.
With the 40D fabric weighing about 55g/m2, it is on the heavy side for tents.
However, it may be used for groundsheets in many tents of the mid-range weight classes. It is also often used for lightweight outdoor clothing, backpacks, and sleeping pads!
What is 40D Ripstop Nylon?
40D ripstop nylon is even stronger than ordinary 40D nylon as it has thicker threads (up to 80D) woven into its fabric.
If you require more strength for a piece of nylon fabric, the ripstop sewing technique is applied. This is standard for most tent materials these days.
Is 40D ripstop nylon waterproof?
Without coating, 40D nylon is considered highly water-resistant, however, if coated by PU of silicone coating it can become completely (5000mm hydrostatic pressure) waterproof. 
40D vs. 20D Nylon
40D nylon is woven with threads that are twice as thick as those used for 20D nylon. This means a much stronger fabric, but also a heavier one.
If strength is desired over weight, 40D nylons should be used but if weight is a priority, 20D nylon is better.
What is the lightest and thinnest nylon fabric?
Technically, nylon can currently be made down to a thickness of 7D, which is the lightest nylon material available.
Although rarely used, it is possible to make tents with a flysheet density of 7D. Apart from being super light at only 19 g/m² 7D fabric also packs down really small, which may also be of importance if pack space is very limited.
The material often goes under the name 7D silnylon emphasizing that it has been treated with silicon (SI) for improved waterproofing.
7D nylon is not really strong enough to be used for tents of any significant durability standard, but some brands do make extremely light tents out of 7D like the Big Agnes Scout 1 Platinum tent or the One Planet Goondie 2 tent.
7D Nylon Weight
7D weighs only 0.8 grams per 1000 meters of thread. It is the only nylon material to go under 1 gram per 1000 meters of thread! This amount to only 19 g/m² for finished (untreated) rip stop 7D fabric woven for most purposes.
10D vs. 7D Nylon Fabric
10D is slightly heavier and stronger than 7D nylon, but I think that this difference is crucial when we go down to these fabric densities – every micron counts!
The 10D fabric functions quite well for tents, and I have used 10D tents for pretty rough adventures where they have done super well.
Most 10D tents are super light and you will not gain much by going to the extreme of 7D. It will maximally save you 30% weight and at a sacrifice of more than 50% durability.
What about stronger nylons?
There are many stronger nylon fabrics out there such as 70D and up to 1680D, which you can read more about here.
The strongest nylon to be widely used, however, was the tightly woven 680D Ballistic Nylon which was used for jumpsuits and flak jackets worn by pilots during WW2.
There are also fusion materials made by blending nylon with other fibers such as kevlar or cotton to give them higher strength or durability. One such material is Cordurathat is used to construct more durable clothes.
However, these thicker types of nylon fabrics are not used for tents as they would be far too heavy and many good alternatives exist at this thickness.
Tents, after all, do not need to be as strong as ballistic jumpsuits (!) so a cheaper fabric like polyester will do for even the most strength critical tent sheets.
However, if you are really serious about strength and ultralight tent fabrics, you should consider looking into the Dyneema fabric I have recently written about. It is basically the strongest and lightest tent material out there!
