Atherton AM.150
A Unique and Unclassifiable bike!

March 15th, 2023

Simon Andre from VTT magazine knows his stuff. As well as 15 years in the bike industry including time as a product developer and 6 years as VTT’s tech editor he’s a National and World Cup level racer in XC, DH and Enduro … and a current French Enduro National Champion in Masters. He rode the AM.150 in size 480mm (470 was probably his ideal size but our demo fleet is still limited!) and he thoroughly tested it “on the typical anti-flow trails of South of France” as well as at French Alpine Bike Parks. It’s fair to say that Simon loved the bike, “one of my favourites” and was pretty sad to have to send it back to us!


First Impressions/ Need to know

Simon Andre: The AM.150 doesn’t look like other frames; in fact, the round tubes and rather bulky lugs rather remind me of the first carbon road bikes from the 80s. Except that on the Atherton, the technology used comes directly from aeronautics and F1 car racing and the connecting parts of the frame are 3d printed in titanium...

At Atherton Bikes, the most important thing is performance… design decisions are all governed by function. Personally, I rather like the aesthetic because it stands out, but what really blew me away is how the bike performs.

The brand offers 22 sizes, so to avoid confusion the website has a “Fit Calculator” that takes into account your height, your crotch and also your arm span. If 22 sizes aren’t enough, there is also a custom sizing option; it’ll cost you a little more, but it’s mm perfect…

The AM.150 is built upon the DW6 suspension platform developed by American expert Dave Weagle. The “6” in the name refers to the 6-bar linkage. At first glance, it’s not very different to a simple “four-bar” linkage like we see a lot on the market, but a four-bar system doesn’t have the same level of refinement, or the same ability to tune ride characteristics. To remedy this, Mr Weagle had the idea of adding two small links at the joint between the chainstays and the front triangle. This separates the dynamic braking and pedalling forces so that there’s no compromise between pedalling efficiency and braking control.

We don’t have numbers on the ratio curve, but you can tell from the rear shock stroke that we are on a fairly low suspension ratio because there’s no less than 60mm of travel in the shock for 150 mm at the rear axle. Many competitors swing between 50 or 55… We will come back to this later but this kinematic is intriguing.

In terms of geometry, we’re on values ​​between a big trail bike and a pure enduro bike. The chainstay length increases according to the size chosen to offer an optimized mass distribution. The front triangle is relatively long but mostly high, with a slack but not overly slack head angle. In terms of assembly, we have the choice between two component kits. The product offering is less exotic than the chassis design, but it's still focused on quality components. It is also possible to choose the frame alone but in this case, the price is relatively high compared with the value offered by the full builds. As a small company, Atherton will be as flexible as you could ever want, even offering upgrades and substitutions on any part of the builds.


The Field Test

In the field, if I had followed the recommendations of the website, I would have needed size 11 with 470 mm of reach, unfortunately, this size was not available in the fleet of test bikes. So I adjusted the length of the stem and the position of the saddle to find the same distance between the contact points while having a larger wheelbase. The suspension was adjusted following the recommendations of the brand. The pedalling position is very nice, high enough up front without sagging in the rear. The suspension is at the crossroads between a trail bike and an enduro bike. The size of the machine and the weight of the whole could well make us lean into the world of pure enduro but I feel that’s is mainly due to the wheels and the fitting of the tyres, we are wearing very sturdy shoes... 

It must also be said that Dave Weagle has a vision of mountain biking that shows up on many bikes on which he has collaborated, and you can certainly feel that influence here, but I love it… Simply put, the AM.150 is a bike that adapts to your pace.

Of course, this machine is not going to turn into an F1 driver. But what I mean is that this bike allows you to ride at your own pace without feeling stuck, when you need to accelerate the response is quick and precise. The chain effect is easily noticeable. The pedalling position is also essential in unlocking the bike’s capability, simply moving a little further forward allows you to quickly pick up speed or compress the suspension. The efficiency is such that we rarely need to adjust the platform leverage but it is sometimes possible to optimize the bike's trim on steep, smooth climbs.

We were amazed at the bike’s capability on steep and very technical climbs. Here we were able to measure the difference with a big enduro which is sometimes hard work, while the AM.150 remains a much more economical bike. We are in the realm of pure all-mountain biking. We can easily rack up the kilometres and hours in the saddle without tiring.  There can be some pedal kickback on big hits, we've seen more neutral bikes, but that's also what makes it accelerate so well. The chain effect fully plays its role when it comes to having fun with the bike or picking up speed.

The frame is not sensationally stiff laterally, especially around the bottom bracket.  The addition of the lower links has a certain impact, as does the structure of the bike itself, those round tubes have been designed to have compliance. Ultra-powerful mountain bikers might feel it but it’s not necessarily a fault for a bike that is mainly all-terrain and a very good descender. The AM.150 is perfectly suited for those who like to tear themselves away from Earth's gravity but on the other hand, it’s way more fun than you’d imagine on twisty trails! It is precise and very predictable in almost any situation. I could maintain speed easily, I felt well balanced and didn't struggle to retain front or rear-wheel grip and I have rarely had a bike of this size so easy to place. The slightly lower lateral stiffness (compared with some carbon frames) is a great help on certain terrains… assisted by the stable and efficient rear suspension.

Downhill DNA

The AM150 is a bike that wants you to push hard, its downhill heritage is clear to see. That’s no surprise, of course, given who designed it.

The bike offers much more descending prowess than your average trail bike. It absorbs impacts really well and doesn’t fall apart when the terrain becomes chaotic and fast. Its stability is incredible due to the perfect-fit sizing and relative length of the front triangle and the rear suspension kinematic feels very progressive to the point of never feeling it lose traction. The front stiffness is also important, it felt like the frame had more to give, I’d have liked to try it with Fox 38s. The AM.150  gives you the confidence to attack but it does require you to be physically present, especially since the rear tends to stay quite high in the travel. Fortunately, the braking is perfectly managed and we can brake really late and hard when the need arises. After a certain speed, the bike has to be held firmly and you have to crash into it like a real racing bike, I certainly reached my limit more often than the machines…

Finally, the AM.150 is pretty minimalist. There is no storage box or even support for a tool holder.  It has slim and minimalist frame guards.  The bikes do have port-to-port cable routing though some purists may be disappointed not to have an external routing. Still, you won't fall for an Atherton if it's just to look like your buddy. 

This bike is a kind of mellowed prototype which offers impressive behaviour somewhere halfway between an enduro bike and a big trail bike. It’s easy to handle and allows you to have fun on a wide variety of terrains, whatever your riding level. Ok, it has a weakness for the descents, but without penalising you on the climbs. This is a bike for all-day adventures with the robustness to go anywhere, but many enduro competitors will also be seduced. This machine caught my eye and it is with great regret that I had to return it… 



Size: 12 (480 R)
Top tube: 620mm
Seat tube: 415mm
Headset angle: 65°
Seat tube angle: 78° Tube height: 125mm
Chainstays: 438mm
Total wheelbase: 1246mm
Bottom bracket height : 342mm
Reach: 480mm
Stack: 641mm


Efficiency 4/5
Comfort 4/5
Handling 4/5
Stability 4.5/5
Price/equipment 4.5/5
TOTAL: 16.8/20