Polygon Square One - Dirt

Mountain Biking Magazine


Trail and Enduro Bikes

Polygon Square One

Polygon strides boldly into new territory

“So here’s our new 180mm all-mountain bike. You’re going to climb it 4,000 feet this morning. Oh, and you have to run it wide open and there’s no lock-out lever.” Safe to say I was sceptical at the start of the launch for Polygon’s new flagship enduro bike.

Photos: James Smurthwaite/Dennis Yuroshek

This bike means a lot to Polygon. For years, the Indonesian brand has been chasing the competition, working inside the box of the latest trends. For the first time, they want to do something new. The result is the Square One, a bike that they believe will revolutionise how we look at mountain bikes.

The concept has been in designer Darrell Voss’ (of Klein and Suntour fame) head for 25 years. When Polygon approached him to design them a bike in 2010, he found the company who could finally make his vision a reality.

It’s instantly eye catching. Chunky single stays are dominant feature along with a green-on-green paint scheme that make it look like a sci-fi military vehicle. And no, despite appearances, there’s no hidden motor in that chunky tube above the bottom bracket – more on that later though.

So what’s different? Voss thinks that the bike industry has an over-reliance on damping, claiming it looks for progress in terms of shock technology, not in kinematics. The climbing-switch is his biggest personal bug bear. He sees it as a lazy shortcut from designers who don’t really understand how to build a proper suspension platform.

Not a lock out in sight

To prove this, he has brought his R3ACT suspension system to the table (the name being an homage to Newton’s Third Law). The idea is to reduce the responsibility of the shock and instead increase traction through the balance of forces.

If you want to know the minutiae of how it works, you’re out of luck. Darrell is deliberately obtuse, even when asked directly about it. He says: “If I were to explain every detail of design or how the kinematics were tweaked, would that change your perception? I want to eliminate all this tech talk and keep it about riding. The industry has been so caught up in marketing acronyms and not wanting to miss the next wheel size variation that suspension design has stagnated and we’ve forgotten how good it feels just to ride.”

Voss has his design trademarked to the hilt – good luck copying it

In short though, it’s a modified four bar system where the secondary link is placed below the primary link. In the stay is a 43mm slider that adds stiffness but also connects the front and rear frame structures. As this slider changes angle, it keeps the rider on a plane, apparently providing a better platform from which to pedal as the head angle isn’t changing as you change gradients.

A look at the bottom of the slider on a fully compressed prototype

Novel, new and something he believes will be revolutionary. This is a man who wants to provide that “one bike to do it all” experience but is doing more than simply designing a “longer, lower, slacker” bike to do it.


So, is this all pixie dust, or is there something going on here? Well, as it stands, the bike runs the Float X2 with 60 per cent less damping than the lowest currently on offer from Fox. In fact, you could argue they should be even less restricted as we ran them wide open with no room for adjustment. It’s also worth noting that, while we weren’t on the most challenging terrain, nobody (including Mick Hannah and Kurt Sorge) bottomed out the shock on the whole trip.

There's no damping in the slider, it's just a guide
This prototype is nicknamed "big, black 1"

Up front a long travel Fox 36 handles things. We rode the 180mm version but there are plans to spec a version of the bike with a 170mm fork for those who want a little bit more climbing performance. The 36 remains one of our favourite forks, even in this long-travel guise.


Top shelf basically. Eagle XX1 drove the bike but even on the lowest spec model you still get Eagle X01. The extra range was welcome, even on a bike that climbs as efficiently as this, but we’d question the wisdom of having such a large dinner plate with a long derailleur on an aggressive 180mm bike.

The rest of the Square One is slathered in carbon. Bars, stem, wheels. The result is a bike that looks chunky but is still claimed to tip the scales at just over 30 lbs without pedals.

Finally the seatpost comes with a custom head that offsets the saddle back to retain the desired seat tube angle without having to restrict the path of the rear wheel. Neat.


If Polygon wanted a bike that climbs well, it’s safe to say it has it. I’m far from a whippet so for me to climb the height of Ben Nevis on a 180mm bike in a day and not want to throw the bike in the river afterwards, it must fit the bill. The sensation takes some getting used to as you feel you tower over the top tube while seated on steeper ascents but just keep pedalling though and the traction kicks in, pushing you up to the top – it’s a true “you have to ride one to believe it” sensation.

On the descents the bike feels bottomless and confidence inspiring. It has more usable travel than Mick Hannah’s downhill bike (when you take into account the amount that’s lost to sag) and you really do get the feeling there’s plenty of support here. It’s a plougher of a bike without question. Point it at some rocks and it feels floaty, almost too easy.

The R3ACT system is designed to push the rear wheel downwards at every opportunity, keeping the suspension noticeably more active than a lot of other bikes under heavy braking. The bike makes great use of the Fox Float X2 and you really feel the benefits of the reduced damping.

It does require some serious body English at lower speeds but get it up to 15mph plus and it starts to reward you with a more lively feel.

The trails we rode out in Oregon were probably a bit tame to push this bike to its limit but spring snowfall stopped us from accessing any of the real burly terrain on offer. We’re hoping to bring this bike back to the UK for a real shakedown in the near future.


For British conditions, I have concerns about the amount of rear wheel clearance, especially underneath the integrated mudguard. It got clogged up multiple times while pushing through snow and I also caught a pine cone in there during one run that had to be bashed out. There is currently 20mm but it’s worth saying that smaller tyres will be specced on the production model than the 2.6″ Marys we were using.

The bottom bracket is also super high at 354mm (-3mm drop) when we’re used to the corner shredding antics of bikes such as the Radon Swoop running a -21mm drop and 170mm travel.


Polygon set out to make something new and different, and they’ve achieved it – there will be no mistaking this bike when you see one in the flesh.

This is without doubt a great bike – in the first two days I played a strange game of trying to convince myself it didn’t have 180mm of travel – whether it will be the revolution that Polygon claims it will be is yet to be seen.


Price: TBC


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