Help - Nylon tent ratings comparison

When tents are rated 40d or 70d I am assuming the higher rating is more durable…is this correct? There are other factors to consider to such as R/S, Sil/PU, 5000mm or 3000mm, tafeta…what do all these mean?

For instance:

Which is better, or more durable?

Fly material: 40d Nylon R/S Sil/PU

Floor material: 70d Nylon 5000mm

Canopy material: 40d Nylon R/S


Fly material: 40d Nylon R/S 3000mm

Floor material: 70d Nylon 3000mm

Canopy material: 70d Nylon Taffeta

I have tried to google this stuff and cannot find anything. The two tents I am trying to compare are the Marmot Aeolos and the Marmot Bise. They can be found here:

d= denier
My dictionary defines denier as a measure of fineness. I interpret that to mean it refers to thread count. Higher numbers = finer threads = more of them per linear unit. May refer to threads per linear inch, but I am not sure of that.

Bicycle clincher tire ratings for their casings often provide such ratings as “tpi” which means “threads per inch.” In that case, the higher counts are definitely more desirable, as they indicate better flexibility.

I would not interpret denier to mean durability, though it might mean better raw ability to resist water penetration. Since all nylon tents are coated, this might not mean much in real life.

Sil = silicone coating

PU = polyurethane coating

Different coatings require different seam sealants.

Taffeta is a type of weave/surface, as is ripstop. With taffeta, all the threads are homogeneous. With ripstop, thicker threads crisscross to form a grid among the finer threads, at intervals of less than 1 cm. The reason for ripstop is to provide some means of stopping tears while allowing use of lighter fabric overall. Ripstop will still rip, but the rip is more likely to stop once it hits the thicker thread.

I have no idea what you mean by 5000mm or 3000mm, unless you are looking at linear dimensions given for non-English buyers. 5000mm is roughly 16 ft.

Thank you for the info! When I mentioned the 3000/5000mm i copied that part directly from the marmot site. It is listed below exactly as it is listed on the site.

Marmot Aeolos

Fly material: 40d Nylon R/S Sil/PU

Floor material: 70d Nylon 5000mm

Canopy material: 40d Nylon R/S


Marmot Bise

Fly material: 40d Nylon R/S 3000mm

Floor material: 70d Nylon 3000mm

Canopy material: 70d Nylon Taffeta

Thanks again for taking the time to reply!

According to #3 son, the rating is the water submergence in mm that it will take to make the fabric pass water. the higher the mm rating the more water pressure it will withstand before it leaks. Never stuck a tent under that much water.

Tent boats?
Hey, if the tent is rated to 5000mm, does that mean we can set sail in it?


Very interesting definition; thank your #3 son, please.

canopy durability
Seems others have covered threads and coatings.

The only thing I may suggest is to think about polyester tent flys. Nylon stretches when wet (thus sagging fly) and deteriorates under sun (thus shortens tent life). It is my understanding that polyester minimizes both those problems.

just my 2c…


(Denier is a rather bizarre measure of yarn size. It is the weight in grams of nine kilometers of yarn!)

One other thing
Dont buy EUREKA Tents, there are MUCH better tents that DON’T come with a jug of seam sealer that are cheaper but A TON of better quality. They dont need the SEAM SEALER cause the seams are taped from the factory.

This is personal experience talking

Tents and seam seal
To each his own, but any leak at all can make your trip less enjoyable. Take the time and seal the seams even if they are factory sealed. You’ll be happier in the end.

Not true
I have a Eureka Mountain Pass 1 XT and a Mountain Hardware Hammerhead-2.

BOTH of them came with most seams factory-taped, and BOTH advised applying seam sealant goo to the non-taped seams. Which I did, for BOTH.

More important, BOTH have been waterproof and warm. I used the Eureka tent for one month of paddle-camping in Alaska, among other trips.

I am selling the Hammerhead-2 on craigslist, but that doesn’t mean it’s an inferior tent or a superior one. It’s too bulky and heavy for my intended purposes.

Eurekas are not bad
There are lot of different Eureka tents in my collection and none of them leak at the seams. Everyone has been seam sealed and every one has been used in heavy rain and wind by less than skilled Scouts.

There are probably millions of Eureka Timbelines in use and they have more camping nights on them collectively than any other tent in existencs.

Marmot is a good high-end manufacturer and both of the mentioned tents rate well with my in-house gear guru, #3 son. He earned his way thru college working at the now defunct Tent City in Rochester, and still has contacts in the industry.

A lot of my tents are factory seconds from the Eureka factory store in Binghamton NY and none have needed any repairs outside of user abuse. 180# sleepwalkers can break most any tent. For my budget influenced purchases, Eureka always rates high.


I appreciate your experiences but
I paid 290 for a eureka tent and was dismayed when I got a bottle of seam sealer with it. I felt that they wanted me to finish production. There were seams that were not sealed. I sent it back to Campmor (what a great place to do business) and bought a Kelty for 230 that came with ALL the seams taped and sealed. I have used it about a dozen times in wet up to my you know what and have not been wet. For my money I would go with kelty in all of their products. Eureka is way out with me.

Thanks for the help
I ended up going with the Marmot Aeolos tent. Im hoping it will last many years. It was on the expensive side, but I am still trying to get my wife 100% into the kayak camping scene. The last thing I need is a leaky tent that spoils her attitude about taking 2-5 day trips.

I really like my tarptent
but your marmont will work well. Unlike the other poster it is not uncommon for you to have to apply seamsealer. I would go ahead and apply additional seamsealer…

Just a note about coyoteequip’s
comment on Nylon and polyester flies. It is true that Nylon stretches much more than polyester when it absorbs water, and Nylon also deteriorates quite a bit faster in sunlight.

I prefer polyester flies when I can get them (from Kelty, for instance), but it is hard to know whether Nylon flies will be much stretchier in rain or much more susceptible to sun damage, because of different manufacturer fabric treatments and coatings for their fly material. I never noticed wet-stretching in our ancient Gerry tent, or in our Eureka Timberline, and though we used each tent for more way more than a decade, it was the waterproof coating of the fly that gave out, not the Nylon fabric itself.

Good companies like Sierra Designs are sticking with Nylon flies. I have a SD Omega 3-4 season that I very much like for its warmth in the cold, even though I dislike the orange/blue nylon fly color. Sometimes you have to buy based on features and reputation, while trusting the manufacturer on materials.

I suspect I may
eventualy need to use seam sealer but RIGHT OUT OF THE BOX??? Also Eureka customer service leaves a lot to be desired.

I have used the Kelty on a trip where it rained every day. We packed it wet and put it up wet. It was dry inside the whole time- cant say that about the Eureka I paid more for.

seam sealing
In my experience, tents that are factory taped tend to work fairly well out of the box, but seam sealing it at home (with a quality seam sealer) is MUCH drier.

I got a Henry Shires tarptent that I had to seal every seam when I got it. No biggie…took me half an hour. I’m pretty confident that my manually sealed seams are more watertight than factory taped ones, which tend to give people a false sense of security.