Astral O.N.S. Seatpost : Quick Review

Astral O.N.S. Seatpost: Quick Review – by Guitar Ted

I heard about this idea for a seatpost called the “O.N.S. Seatpost” and I thought it was a great idea. One of those “Why has no one done this before?” ideas that makes sense for certain cyclists who are – perhaps – more ‘risk-taker’ characters than others. Although, I’d wager many of us should contemplate such a device. But I’m getting ahead of myself here. Just what the heck is an “O.N.S. Seatpost” anyway, and why should you care?

Astral seat post on a bike in a rural setting
The Astral Seat Post as it appeared on Guitar Ted’s Raleigh Tamland Two gravel bike recently.

Well, the “O.N.S.” part stands for “One Night Stand”, but don’t get the idea that I’m going to get you a hot date by reviewing this item. No….. This is something quite different and unique. A ‘safety seatpost’, if you will, that has a survival kit hidden within it. It’s offered by Astral, the wheel component brand, and it follows a thread which started with companies stuffing tools in spaces unused on bicycles. Like the old Cannondale steer tube repair kit, air pumps in seatposts, or those repair kits that go into handle bar ends, or even the hollow spindles of some crank sets. Let’s take a closer look at the O.N.S. Seatpost now…..

What It Is: Outwardly, the Astral seatpost looks like any other standard aluminum seatpost. It features a black anodized shaft and clamp head made from 2014 T6 aluminum alloy and it comes in two sizes: 27.2mm (tested) and 31.6mm. The length of the seatpost is 350mm. The O.N.S. Seatpost features a two-bolt clamp and 10mm of setback as well.

Okay? So what? It is a standard seatpost, right? Yes- and no– the O.N.S. Seatpost has a hidden survival kit inside its shaft which includes the following items:

  • Space blanket
  • Mini flashlight w/ AAA battery
  • Whistle
  • Waterproof Matches
  • Fire starter materials
  • Strike paper (for matches)
  • Water purification tablets for 3 quarts of water

All that inside a seatpost shaft? Yes. How do they get all that in there? Great question. I’m not sure, and I’ve tried it on another 27.2mm seatpost. Well…..let me explain here. Once again, I’m getting ahead of myself. First let me say that the seatpost is available from Astral’s website and that it costs $99.00 USD.

Contents of the Astral O.N.S. Seatpost on a rock enumerated for ID.
Contents of the O.N.S. Seatpost: #1: Emergency whistle, #2: Strike Paper, #3: Space Blanket, #4: Waterproof Matches, #5: Fire Starter Materials, #6: Mini-Flashlight w/battery installed.

First Impressions: My contact at Astral Cycling told me upfront that he was going to send me an extra O.N.S. kit to photograph because if I pulled out the O.N.S. kit in the test post he sent out that I would never get all the things back in the post again. After getting everything in hand here, I can see that his advice was correct. It’s like those model car kits I used to buy when I was a young child. I’d pull all the parts out to look at them and then I’d almost never get them all back in the box in a way that I could close the box like it was when I purchased the kit. Those magical packaging people are true witches and wizards!

So, getting back to the O.N.S. kit, it has a lot of things in it which could become life-savers – literally – if you find yourself in an emergency situation. At the very least, there are a few things there that might come in really handy if you got lost, or were out too late, or what have you. Astral has an excellent ‘how-to-use’ site for the O.N.S. Seatpost here, so I won’t get into a long description of the how and why for the kit in this review. It bears mentioning that refill sleeves for the O.N.S. kit are available on Astral’s website. (Although, if you get one for the 27.2mm post, you may not be able to ‘re-stuff’ it!)

My take on the seatpost is that it is a decent quality post, it looks fine, and otherwise it is pretty standard fare. The idea for the stuffing of the post with an emergency kit, however, is very interesting, and I think it is compelling for certain situations and for certain riders. Of course, having a survival kit within the seat post shaft does make the entire package weigh more, but it isn’t terrible at 372 grams.

A bicycle lying against a large stone in a rural setting.
Guitar Ted did not experience the dreaded aluminum seatpost ‘zing’ with the Astral O.N.S. Seatpost.

Ride Performance: The Astral O.N.S. Seatpost is aluminum, and there really are no design details to indicate that it should be anything but a standard experience. In fact, I was expecting this post to be a bit on the harsh side. That said, I was pleasantly surprised by how it felt.

I should note that I installed an ancient WTB SST saddle on the post which I love for it’s leather cover and comfort, so the saddle is very familiar to me. While this saddle is comfortable, that doesn’t explain why I felt the saddle was actually not transmitting a lot of vibrations to my backside. Could that be because the bag holding the seven elements that make up the emergency kit was damping those vibrations? I cannot say. I can say that my Raleigh Tamland Two rides very nicely. Maybe it was just that? I don’t know, but this post felt smoother than I was expecting. Actually, it was pretty nice in that regard.

At The Finish: Okay, so having an emergency kit- is this an idea for you? That’s the number one question to answer here, in my opinion. I think that answer is “Yes” for some riders, but with some qualifications. Yes, if you are a solo cyclist. Being self-sufficient means being able to take care of yourself and your needs when and if necessary. This extends to first aid and shelter/survival. It’s kind of the Scout’s way- always be prepared – and I think it is incumbent upon anyone to consider safety who takes to the back country, the sparsely populated rural areas, and the woods, where getting first aid or rescue is difficult. Especially so if you ride solo a lot.

The bag which is inside the Astral O.N.S. Seatpost revealed and sitting on a rock.
The red cap is dislodged from the bottom of the seatpost and then the string can be used to pull the bag and its contents from the seatpost.

Now if you ride in a group, or in more populated areas, that risk is, perhaps, mitigated, and maybe then you may not see the necessity for such a component. Perhaps you get this post for the occasional longer ride, or for bike camping, or what have you, and you swap it over to the bike when you need it. Big, long distance events, where support is not easily accessed or even provided might call out for a post like this one. Swap out your regular post for the Astral O.N.S. Seatpost and there you go.

But there are a few reasons that this post might be a non-starter. First, if you must have a dropper post, well that takes the O.N.S. Seatpost off the table as a solution. If weight, or lack thereof, is a high concern, and having a survival kit is of little concern, well obviously, you don’t go here. Same for aesthetic reasons, or if you have to have a suspension post, or a flexible post. Maybe some of those reasons are petty in comparison to being able to cover emergency needs. Risk assessment….. It’s a thing.

I think this Astral O.N.S. Seatpost is a great start in providing options to cyclists for emergency survival kits within seatposts. However; I’d like to see a longer version for those who have sloping top-tube frames where there is a need for a 400mm post. Perhaps something nicer, say a titanium version, would appeal more to a bikepacker or ultra-distance rider. That said, this seems to be a solid option for those who want to conserve space and yet have that resources for an emergency there if they need it. I like the idea, and if you fit the profile for this product, it is a compelling way to fill a need for safety.

For more on the Astral O.N.S. Seatpost and other Astral products, see their website;

Note: Astral Cycling sent over the O.N/S. Seatpost for test and review to Riding Gravel at no charge. We were not paid, nor bribed, for this review and we always strive to give our honest thoughts and views throughout.


Author: Guitar Ted

Guitar Ted hails from Iowa. Home of over 70,000 miles of gravel and back roads. An inaugural member of the Gravel Cycling Hall of Fame and Co-creator of Trans Iowa in late 2004- Guitar Ted has been at the forefront of the growth of gravel events and riding since then. Creator of Gravel Grinder News in 2008, he produced the premier calendar of gravel and back road events. GT joined forces with Riding Gravel in late 2014.

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