what's the difference: polyester/Velocity nylon/ballistics?

I’m looking for a new backpack and I would like to buy the one that will last me the longest.
I’ll list the two backpacks and each of their build fabrics

Backpack 1:

  • 1350 cubic inches
  • 420-denier nylon, 1680-denier ballistics

Backpack 2:

  • 1600 cubic inches
  • 600-denier polyester, 420-denier Velocity nylon

Now, I know what nylon and polyester is; I’ve heard that generally speaking, nylon tends to be the stronger of the two fabrics.
However, I have never heard of “Velocity nylon” or “denier-ballistics” so could someone explain where those two fabrics stand in terms of their durability?


To be fair- I’ve never heard of Velocity… but here we go.

Ballistic nylon is a stronger weave of material. It also carries a lower friction coefficient thus can resist abuse of dull objects better- preferably flat. Ballistic nylon is common on softgoods that see higher abuse-esq situations… like backpacks sliding on the floor, luggage, roller hockey pants- stuff like that.

Polyester and Nylon can share very similar characteristics in fabric. Nylon is generally more expensive- and better in life changing situations… everything else in my opinion could be chalked up to preference.

Of course the difference at the “backpack” level has me thinking that this post wasn’t worth my time in cost it took to write- but I hope you liked it.

Dude- just buy the backpack.

Ok so basically backpack 1 is the stronger of the two
and more useful (due to its ballistic nylon) since I tend to throw my backpack on the ground everywhere

Thanks for the informative response.
Has anyone else heard of “velocity nylon”?

As stated, ballistic is a standard one for tough use but I also have never heard of “velocity” nylon.


There’s the link for the backpack with “Velocity Nylon”
Quite strange for such a big store to mistype something like this

Go for pack #1. 420D is still fairly burly, but much lighter weight than ballistics. I personally don’t like the look of ballistic nylon in general, but if you are looking for durability, it doesn’t get much better.

In fact, I think Timbuk2 is pretty much the only company that uses ballistic nylon well. 2007 Colors were better, though!

Is 420D Nylon > 600D Polyester?
if so, then Pack 1 it is

The denier describes the size of the yarn in the fabric. Larger number = heavier fabric.

but heavier fabric doesn’t always equate to stronger fabric
my question was if 420D nylon is stronger than 600D polyester, not the size

probably not. although nylon tends to be more abrasion-resistant than polyester, there is a big difference between 420D and 600D.

Not typically but it depends on the 600Ds backing.

Nylons are typically stronger than comparable weave Polyesters

BUT Polyesters with a 2xPU or 2xPVC backing are more durable than comparable Nylons and much more inexpensive, but heavier weight and more inflexible.

and while the difference between the 420 D Nylon and 600D poly is an extra 180 threads per inch, the backing on the poly can make a huge difference in its cost and durability.

Velocity is a generic name of a weave (like Ballistic, Twill, Oxford, Ripstop, Diamond Rip stop, Diaper ripstop etc) that can be on a bias from Ballistic (ie ballistic is vertical/horizontal, Velocity is on the 45º) and typically runs around 600D.

at least thats what the Korean sample book I have in front of me shows…

bag #1 for durability

bag #2 for weight savings

but ultimately buy the bag fits you best.