Argon 18 Dark Matter Gravel Bike Review: Bent Fork Blades For Comfort?

The Argon 18 Dark Matter gravel bike once again reminded me what gravel riding is all about. While it’s not the most comfortable gravel bike out of the box – wow, it’s a fun bike.

Argon 18 is a brand that is usually associated with racing bikes or triathlons, and as a result, it’s often overlooked by those looking for an everyday gravel bike.

I actually found the Dark Matter by accident while researching gravel bikes. I remember the unique carbon fork was specifically mentioned in the article because its shape is not dissimilar to an old steel fork.

Some reviewers were saying that you could see the fork flexing vertically underneath you – which made me wonder if it would translate to excellent comfort.

I got my hands on a bike to test and the first thing I did was look down while I was riding it. Unfortunately, there was no noticeable fork deflection going on. That might be due to the supple tires and low tire pressure I use (your tires will always deform first).

But you don’t have to see the flex to feel the increased vibration damping of this fork.

I recently conducted a fork vibration comparison test where I compared Argon 18’s fork with the Lauf Grit SL suspension fork, Jamis Renegade ECO fork, and OPEN U-Turn fork. The Argon 18 fork performed very well, even beating the Lauf suspension fork on the fast gravel road vibration test!

While the unique shape of this fork translates into a comfy ride, keep in mind that the shape isn’t crucial for comfort. In my fork test, the straight blade OPEN U-Turn fork offered a very similar level of comfort.

How Comfortable Is The Dark Matter?

When I interviewed Martin Faubert, the chief designer at Argon 18, I learned that the Dark Matter frame was designed to provide stiffness, comfort, and good aerodynamics.

In this YouTube video, you can see how the Krypton frame (on which the Dark Matter frame is based) is flexing under the load. Design choices like dropped seat stays on the seat tube, and the special shape of the seat stays promote a lot of flex and increase overall comfort.

But in reality, much of this improved compliance is negated by a rather long seat tube length on each size that does allow a carbon seatpost to flex properly.

This was crystal clear when I was comparing the vibration results of the Ergon Allroad Pro seatpost on my benchmark bike and the Dark Matter. As my benchmark bike has a much shorter seat tube, I achieved much more flex from the extra exposed seatpost length.

This was a very informative lesson that showed that the lowest-hanging fruit (in terms of comfort) can often be the seatpost.

But this does not mean that the rear of Dark Matter is overly harsh. It just means that to radically improve the rear-end comfort, you will need a solution like a Redshift ShockStop suspension seatpost, which performs equally well no matter how much exposed the seat post there is (the Redshift post is a great comfort equalizer between all seat tube lengths).

How Does The Dark Matter Ride?

One of my first rides on the Dark Matter was after some long rainy days, which resulted in mud everywhere. These tricky conditions allowed me to quickly learn the true nature of this bike.

This is a fun bike to ride. Really fun! It’s not only confidence-inspiring to ride but the quick steering makes it feel very playful. And what surprises me the most is that the quick steering does not result in nervous, twitchy handling down steep forest trails.

The well-balanced, playful handling could be due to the rather steep head tube angle (72 degrees) combined with the 49mm fork offset. Or perhaps it has something to do with a rather short chainstay length (428mm). Or maybe it’s the modest BB drop (70 mm) that does not make the bike feel too ‘planted’ like the Specialized Diverge.

Realistically, it’s a combination of all of these things.

Love At First Sight?

Not at the start. The first thing I noticed was how tall the front of this bike was.

On my medium test bike, the head tube measured 171mm, and it also had a special 30mm rise headtube spacer. This means that the headtube effectively measured over 200mm. This is a lot for a medium gravel bike and is in the territory of the very tall Specialized Diverge.

For me, the bike was a touch too high, but luckily a 0mm headtube spacer is available which would get my handlebars back to the height I prefer.

Combine this with my eternal issue of being in-between sizes of bike frame (on this occasion between S and M) and I needed to make two changes: I swapped the 100mm for a 90mm stem, and I slammed the stem down to -6 degree to compensate for the high front end of the bike.

After those two changes, I could focus on the ride without any discomfort coming from the riding position.

Argon 18 vs My Benchmark Bike

For the vibration test, the Argon 18 Dark Matter used its standard carbon fork. It was fitted with Challenge Gravel Grinder 700C x 42mm tires running at 25 psi, or Soma Cazadero 700C x 50mm tires at 21 psi.

I also tested it with the following saddle and seatpost combinations:
(1) Prologo Scratch RS + FSA K-Force carbon
(2) Brooks C17 + Ergon Allroad Pro
(3) SQlab 612 + Redshift ShockStop suspension

My benchmark bike (Jamis Renegade) used a Lauf Grit SL suspension fork, Redshift ShockStop stem, and Soma Cazadero 700C x 42mm tires at 25 psi.

I also tested it with the following saddle and seatpost combinations:
(1) Brooks C17 saddle + Ergon Allroad Pro seatpost
(2) SQlab 612 saddle + Redshift ShockStop suspension seatpost

Vibration Test Results

You can see my vibration measurement procedure & outdoor test courses HERE.

At the rear of the bike, the Argon 18 was reading rather high vibration numbers for both the bumpy forest trail and fast gravel road. Using the K-Force seatpost and Prologo saddle, there were approximately 24% more vibrations than on my benchmark bike with the Redshift ShockStop seatpost.

The vibrations on the Argon 18 were reduced a bit when using the Ergon Allroad Pro seatpost. But interestingly, they did not reduce as much as on my benchmark bike – I suspect this is due to the Argon 18’s longer seat tube length which prevents the seatpost from being able to flex as much.

It was only when I installed the Redshift suspension seatpost on the Argon 18 that I could reach great levels of comfort – the same vibration levels as my Jamis.

The front end of the Dark Matter was proving to be quite comfortable from the start. From my previous carbon fork field test, I knew the Dark Matter fork offered great compliance.

When I put a 50mm Soma Cazadero tire on the front of the Dark Matter (21 psi), I was able to improve the front comfort by 7,5% on the bumpy forest trail and 10,5% on the fast gravel road. But keep in mind my benchmark bike with all the comfort accessories was still significantly more comfortable… even with 42mm tires (14,5%).

On the fast gravel road, the Dark Matter with a 50mm tire at the front (21 psi) was actually slightly better at absorbing high-frequency vibrations (2,7%) than my benchmark bike. This is despite the benchmark bike using a suspension fork and suspension stem!

The last thing worth discussing is that the stock Challenge GravelGrinder tires on the Dark Matter seemed to offer a very high level of comfort (similar to the Soma Cazdero).

Would I Buy The Argon 18 Dark Matter?

For the sheer fun of the ride – yes! But only if I could afford to own two gravel bikes instead of one…

The Argon 18 Dark Matter makes a very good first impression that stays with you – it makes you want to ride gravel for pure fun and enjoyment. This could easily be the only bike you need.

The Dark Matter is fast and it’s comfortable. The fork offers a lot of compliance, and if you find yourself wanting more, you can easily fit a front 700C x 50mm tire to get the smoothest possible ride.

In terms of rear-end compliance, I’d definitely recommend a Redshift ShockStop suspension seatpost to reduce vibrations coming up from the road or trail. This is partly because the seat tube is long for its size, and will not allow you to achieve the right amount of flex from a carbon seatpost.

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