At the product launch in Oregon, USA, the enduro bike had to show what it can do.
My pulse is racing, my thighs are burning and a glance at the GPS heart rate monitor on my wrist confirms it: I have just ridden 650 metres uphill. And over a distance of less than nine kilometres and on narrow paths. Not an extraordinary achievement in itself - but I managed this climb on the Square One EX. This newly developed enduro bike from Polygon offers a whopping 180 millimetres of suspension travel at the front and rear. And yet it didn't show any weaknesses on the climbs, but always shone with great traction. In disbelief, my gaze wanders over the striking main frame to the voluminous, raised swingarm and on to the bottom bracket area of the Square One EX.
This is the centrepiece of the R3ACT kinematics, which the Naild development office has been working on for ten years (see interview with Darrell Voss). The front, short lever of this four-bar linkage is located far in front of the bottom bracket. The second lever runs partly on an oversized piston rod, called a slider, which has two functions: The position above the bottom bracket and the angle of the slider ensure that the rear triangle is largely decoupled from impulses from the rider. Even on steep ramps or when pedalling out of the saddle, the rear triangle does not buckle. Thanks to the generously dimensioned stanchion tube diameter of 43 millimetres, the slider also contributes greatly to the rigidity of the frame.
After half of the climb, a twisty section with constant ups and downs awaits. Here, the Square One EX feels efficiently like a twentyniner with 120 millimetres of travel. The rear wheel maintains contact with the ground at all times and therefore provides plenty of traction without completely isolating the rider from the ground. A little more physical effort is required in tight bends, but the new enduro bike from Polygon can hardly be pushed to its limits downhill: The faster the pace on the trails through the rainforest in the Cascade Mountains, the smoother the bike seems to run. On two days, none of the test riders managed to get the rear end to bottom out - not even the two Polygon team riders Mick Hannah and Kurt Sorge.
Because the riding position is also suitable for long tours and the weight is not too high at just under 14 kilograms, the Square One EX is not only suitable for pushing your own limits and chasing the best times. This enduro bike actually climbs far too well for its downhill qualities. Polygon now has a real all-rounder in its quiver.
Conclusion by Laurens van Roojien, test author:
Laurens van Roojien, test author Weighing a good 14 kilograms, the Square One EX is no climbing specialist. But for an enduro bike with 180 millimetres of travel, it offers amazing qualities on the climbs, and thanks to the efficient R3ACT kinematics, all-day tours are easily possible. As the Polygon leaves nothing to be desired on the descents, the bottom line is an extremely wide range of use.
Technical data
Weight 13.4 kg
available at Specialised trade
Price is not yet fixed
Front / rear suspension travel 180 mm / 180 mm
Material / Sizes Carbon / M / L / XL (46.5 cm)
Weight o. P. / frame 13.4 kg / 2750 g (without damper)
Fork / damper Fox Factory 36 Float / Fox Factory Float X2
Cranks / gears Sram XX1 Eagle / S. XX1 Eagle, 12 gears
Gear ratio / handlebar width 32; 10-50 / 800 mm
Brake system / Disc Sram Guide Ultimate / 180/180 mm
Telescopic support Kind Shock SIO Offset, 150 mm
Impellers E13 TRS Race Carbon Boost system wheels; Schwalbe Magic Mary 27.5 x 2.35 tyres
Reach / Stack / BB-Offset 462 / 602 mm / -3 mm
You can read this article or the entire BIKE 7/2017 issue in the BIKE app (iTunes and Google Play) or buy the issue in the DK shop reorder:
Darrell Voss: Four questions for the founder of Naild
BIKE: What distinguishes the R3ACT kinematics from other designs?
DV: Up to now, almost all considerations regarding kinematics have been based on motorbike know-how. This only makes sense to a certain extent, as the differences are huge, from the quality and quantity of the power steering to the ratio of rider weight to vehicle weight. We took this into account right from the start when designing the R3ACT kinematics: We balance the forces that occur in order to prevent unwanted movements of the chassis. In doing so, we do not rely on damping, as this inevitably leads to a loss of energy.
What is the biggest advantage of your suspension system?
We designed the suspension from the ground up: the key to optimum control is to keep the wheels on the ground or to guide them over obstacles as efficiently as possible - and not to isolate the rider from the ground. We call this ground tracing: the tyres should follow bumps as precisely as possible. Because the slider is part of the swingarm and not the main frame, our rear suspension also works very evenly over the entire suspension travel.
Explained in two short sentences: What is the slider for and what is it not for?
By balancing the resulting forces of the drive and the rider's acceleration, the slider reduces the required compression damping by around 40 per cent. In addition, the slider makes a decisive contribution to the rigidity of the chassis and therefore to precise handling, as it ensures that the long swingarm is guided cleanly. The slider is not a shock absorber, is not pressurised and only contains a little oil for lubrication, but none for damping.
Is the R3ACT kinematics suitable for all applications and driving styles?
The rear triangle construction can utilise its advantages in all disciplines - from marathon and cross country to enduro and downhill. At Naild, we are currently working with various manufacturers to develop other platforms with a narrower range of use than that of Polygon's Square One EX.
You can read this article or the entire BIKE 7/2017 issue in the BIKE app (iTunes and Google Play) or buy the issue in the DK shop reorder:
