Polygon's 180mm-travel Square One EX9 doesn't resemble anything else out there, and it features the novel looking R3ACT suspension layout that is claimed to allow the bike to defy expectations of how a long-travel machine should perform, especially in terms of pedaling efficiency. ''The Square One EX Series is a departure from the old way of classifying bikes and creates a new paradigm where travel no longer determines discipline,'' Polygon says on their website, which is a pretty bold claim, even in our little cycling world where every brand says that their creation is the latest and greatest.
So, can an all-mountain sled with 180mm of travel really feel like an efficient trail bike? And even if it can, does that make it the "one bike" that other testers have said it could be? Let's find out.
The angular shape of the tubing makes the EX9 look as if it belongs in a Ridley Scott sci-fi movie.
With a carbon fiber front triangle and swingarm, carbon wheels from e*thirteen, an XX1 Eagle 12-speed drivetrain, and Fox's high-end suspension, the 27.5'' wheeled EX9 model tested below sits at the top of the two-bike range and goes for $8,499 USD. A bare Square One EX9 frame and Fox Factory Float X2 shock sells for $3,499 USD, should you want to assemble your own to have it come in under our test bike's 32lb 5oz (with the 2.5'' Magic Mary tires that it showed up with) weight.
Where to start? There's a lot to talk about with the EX9, that's for sure, but it also has a marmite thing going for it - people seem to either love or hate the bike's polarizing appearance. I think it looks like an e-bike without a motor (aka the best kind of e-bike), but there are some angles, especially the three-quarter view from behind, that make it look simply awesome. Then I take a gander from a different angle and it seems as if it may as well belong in a Ridley Scott sci-fi movie, and I don't mean that as a compliment. One thing's for sure: it's unique, which is a good thing in my books.
All lines run inside the frame, with internal guides making maintenance easy.
The frame is carbon fiber front to back, and I suspect that it's probably easier to build the EX9's complicated shapes, especially down by the bottom bracket, out of carbon rather than aluminum. The frame tubes sport a boxy shape, while the dropped top tube provides more than enough clearance for even the stubbiest of riders. The elevated swingarm (who remembers the Trek VRX?) is utterly massive in places to supply ample rigidity, bulging inward towards the wheel where clearance allows and also being home to internally routed shift and brake lines.
A dual-action, Boost-sized 12mm thru-axle ties the back of the bike together, and a bolt-on fender gives the EX9 a very moto-esque appearance. Another guard on the underside of the down tube wards off pointy things that are looking to cause damage.
The massive swingarm and bolt-on fender might have some riders looking for the engine.
A set of ISCG tabs around the PressFit bottom bracket shell means that you can run anything from no guide to full-guide, and the KS dropper post's cable is routed internally from the bike's head tube. One thing that I can't get past is the lack of a water bottle mount. Sure, there isn't room inside the front triangle, but what about one on the underside of the down tube? No luck, unfortunately, which is a shame given that the EX9 is such an impressive pedaling beast. So, if you're considering this bike, also consider that you'll need to wear a pack of some sort during the majority of your riding.
The EX9's 180mm of rear wheel travel is controlled by Darrell Voss' novel R3ACT suspension design.
The EX9 has 180mm of rear wheel travel, a number that's typically the domain of heavy hitting freeride bikes rather than a machine designed to be pedaled around in an efficient manner. But that's exactly what the big Polygon is made for, regardless of its generous and extremely forgiving suspension. The idea is that travel shouldn't define the ride: "I don't believe that suspension travel should necessarily be part of that equation," says Darrell Voss, the brain behind the EX9's unusual looking rear-end. "Let's face it. Most riders are out there to have fun, and they can only afford one bike. If it pedals efficiently, what is the downside to having more travel?"
But that's the trick, isn't it; to make a bike with 180mm of gushy, ground-hugging travel pedal without making the rider feel as if he's skipped leg day for his entire life. And that's exactly what Voss believes that he's come up with.
The nearly hidden stanchion is completely empty, but there is an air bleed button in case any pressure gets built up inside of it.
The EX9's massive carbon fiber swingarm is attached to the front triangle by way of three elements: the aluminum clevis that drives the bike's custom tuned Float X2 shock, a short link at the head of the swingarm and, most interestingly, a sliding element that's nearly entirely hidden from view. This sliding element acts as a short link but is also more dynamic than a link could ever be, extending in length as the bike goes through its travel.
The swingarm slides in and out on this hard anodized stanchion, and while it may look like a pint-sized shock, it's actually completely empty. Its job is to counter unwanted suspension movement, and also to provide an anti-squat vector that, unlike the present dual-link suspension designs, stays relatively consistent through the bike's gearing and travel. In order to do this, Voss has positioned and angled it precisely to balance suspension action and pedaling forces, but the system should still feel active under even the smallest of impacts at the rear wheel.
All of the above requires a proprietary Fox Float X2 shock with extremely low amounts of damping - no, you can't go and put any other shock on the EX9 and expect the bike to work as intended. Voss also found that the design is so efficient that there's no need for a low-speed compression pedal assist switch as many all-mountain and enduro sleds make use of, despite the Polygon's 180mm of travel. Setup is also said to relatively simple: "Sure, R3ACT's kinematics are complicated to describe," says Voss. "But, the rider should never have to think of that. Set the Square One's sag at 25-percent, get the low-speed rebound close and go ride. There is nothing else to do."
So that's exactly what I did, and below you can read the results.
The EX9's unusual suspension system requires an equally unusual approach to setup, but it's one that I suspect a lot of riders will be happy about. First, set the Float X2's spring rate to twenty-five percent sag, a number that's a touch lower than a lot of modern all-mountain rigs. Next, fiddle with the rebound but let it return quicker than you think is correct. Oh, and pretend those two compression dials on the X2 don't exist - you pretty much don't need them. So while the design may look complicated, setup is anything but. My settings were as follows: 165 PSI, high-speed rebound 23 clicks out, low-speed rebound 19 clicks out, high-speed compression 23 clicks out, and low-speed compression 19 clicks out. In other words, nearly wide open all around.
I generally prefer slower, more controlled low- and high-speed rebound settings, especially on a bike with a boatload of travel like the Polygon. But what I like and what Voss says to do are two different things. I trusted Voss on this one - you know, because he designed the damn thing - and, after balancing the 180mm-travel 36 to match the rear-end, headed out for what was an eye-opening first ride. And second ride. And also third ride. Actually, all of my time on the EX9 was eye-opening.
As it turns out, the interesting looking bike delivers equally interesting performance that's unlike anything else out there.
I'd heard from other testers that the EX9 does pedal as well as Voss and Polygon claim, but having a bike actually live up to the hype attached to it isn't possible, right?
Well, it almost never is, except for this one time. The Square One's pedaling efficiency shouldn't be possible for a 150mm-travel bike, let alone one that sports 180mm of extremely active, supple suspension. Yet that's exactly what's happening with the big Polygon. Despite all its travel, the green machine actually does move forward very much like a short-stroke trail bike, albeit a chunky trail bike. You need to try it to believe it.
The Float X2 shock is remarkably and unbelievably still under pedaling loads - remember that there's no pedal-assist crutch, either - with it barely moving into its stroke under even the hardest burst or my efforts to turn the cranks over in squares rather than circles. Sure, the rear-end will feel open when you start throwing your body weight around, but the Polygon will blow your mind if you pedal like a sane person. I feel like I might be over-selling the efficiency but, in nearly twenty-five years or riding, I can't recall a bike that's surprised me as much as this thing; it's that impressive.
Forget your assumptions about suspension travel and pedaling efficiency - the two can be separated, it seems. The 180mm-travel EX9 pedals like an efficient trail bike.
All of the above is all well and good, but no amount of pedaling competence is going to change the fact that the Polygon is an all-mountain bike that weighs close to some feather-weight downhill sleds. Get trucking up a gravel access road and the bike will move forward with astounding brilliance, but the trail bike efficiency isn't matched by trail bike acceleration or handling manners when it comes to a set of tight switchbacks or a tangled mess of a climb. It isn't a handful, mind you, and maybe it's just because the green machine is such a good pedaling bike that my expectations were a bit high when it came to tricky singletrack climbs, but it's not a breeze to get the Polygon up chunky, slow-speed pitches, even compared to longer and more relaxed bikes like the Rocky Mountain Slayer or Ibis HD4. The EX9 isn't too slack or too long (it's actually steeper and shorter than many other all-mountain bikes) but I often had the feeling that the bike had a massive presence on the trail, much like you're trying to thread a loaded dump truck through tiny side streets.
The rear-end is also somehow extremely active despite the said efficiency, and it'll take in the smallest of impacts without hanging up, so there is a massive amount of traction on hand should you need it, but the bike still feels a bit unwieldy when handling skill counts for more than horsepower. I also felt like my weight was always biased too far rearward, which was amplified as the grades got steeper. If the Square One were in my garage, I'd ditch the stock KS dropper with its set-back for a post with a zero offset head, regardless of the effective seat tube angle being 73.5-degrees.
I feel like I might be over-selling the efficiency but, in nearly twenty-five years of riding, I can't recall a bike that's surprised me as much as the Polygon; it's that impressive.
Okay, of course it's not going to be a technical climbing savant - that's not what the Square One was made to do - but I suspect that some riders considering the Polygon aren't going to give a rat's ass about this fact. For them, it's about just getting to the top, and there's no denying that the EX9 is more efficient than most trail bikes could ever hope to be. But it's not a trail bike, it's an 180mm-travel all-mountain sled that's made to go through anything and everything, and it also happens to be inconceivably efficient.
It took a handful of rides for me not to be constantly surprised by the Polygon's pedaling abilities, but it took even longer for me to wrap my head around what the bike does at speed. And, depending on what you want from your all-mountain bike, the EX9 could be either the best option on the market or far from it. Let me explain...
Traction is a funny thing; most of us don't really notice it until it disappears, and when it does it happens in a near instant. But what if it doesn't disappear? Well, that's what it's like to ride the EX9, and it's a surreal feeling at first. My test bike came shod with Schwalbe's beefy Magic Mary tires, rubber that I'm both intimately familiar with and have a healthy dislike for (there are too many wet roots and woodwork here for me to be a fan) but, on the heavy hitting Polygon, they felt like some of the grippiest tires I've ever used. And cornering, my God can this thing get around a bend. It actually doesn't feel particularly low or anything, but with traction that only seems to get better as the ground gets rougher, the Polygon feels riveted to the deck. It just never seems to get flustered, and where any other mid-travel bike is getting knocked around, the Polygon stays stuck and can hold a line through a corner regardless of roots, rocks, or off-camber anything.
Speed comes so easy on the EX9 that its 66-degree head angle often feels a bit nervous for my liking; I'd wager that this bike is well suited to a more relaxed front end, even if it did come at the cost of killing what little low-speed perkiness the Polygon possesses. The suspension and geometry feel a bit contrasting, with the former constantly yelling in your ear to let go of the brakes while the latter is asking you to pay attention. Weirdly, and completely contradictory, it's not a lively, perky bike, despite the front end sometimes feeling a touch pointy.
I've never ridden a bike that's felt so surefooted through any type of corner as the EX9.
Interestingly, it actually rides a lot like the Fox shock's rebound settings are much slower than they actually are, and I can see why Voss recommends minimal damping all around. This isn't a playful thing, and running more rebound damping will basically kill what little friskiness the EX9 has to begin with.
The bike's stability is mindblowing, sure, but I fear that it has come at the expense of a ride that feels anything but dynamic. The EX9 nearly refused to be dislodged from whatever line I placed it on, for better or worse, but certainly for the better if you're all about going as fast as possible down a war zone of a trail. I dare say that the Polygon has more composure and poise than some downhill bikes, with it simply taking in and brushing off whatever happens to be going on under its wheels. This is particularly true when on the binders. In fact, braking traction is one of the most obvious differences between the Polygon and other bikes; the suspension stays active and the bike slows down as if you've dropped a literal anchor into the dirt when squeezing the Guide brake levers.
Jumping is... interesting. With the recommended rebound settings being relatively quick, and the front end set to match the rear, I was surprised by the Polygon's comparative unwillingness to leave the ground. Yes, the bike can jump, and it feels as stable in the air as it does on the ground, but I never found it as easy, or eager, to make the most out of natural take-offs as other more conventional machines. I've also never pointed a Honda Goldwing off a jump before, but I suspect that it feels similar to doing the same with the EX9.
I suspect that going for a joyride in the Killdozer would be fun for awhile, but smashing through buildings must surely get old after you've gone through a dozen or so; the same applies to the Polygon.
The flipside of what can feel like near limitless traction and the ability to plow through silly things like boulders, small cars, and also brick walls, is that the Polygon doesn't articulate to the rider what's happening between the ground and its tires. Yes, the bike's composure in hectic terrain is out of this world, but I couldn't help but always think of it as a blunt smashing tool, a sledgehammer on wheels, rather than a laser guided missile like some of today's best all-mountain bikes are. For comparison's sake, I had been swapping between the Polygon and Ibis' new Mojo HD4, a 153mm-travel bike with a slightly slacker static head angle (remember, it has nearly 30mm less travel) and an 18mm longer wheelbase than the green monster. The difference between these two bikes, as well as something like the new Slayer or Slash, and the Polygon is so pronounced that they hardly feel like they've been made to do the same thing, yet that's exactly the case.
The EX9's 66-degree head angle can feel steep at times, but I suspect this is only because the bike's suspension is so capable and there's so much traction available.
While the Slayer and HD4, or many other bikes of the same ilk, can be ridden like a monster truck if one wishes or be made to dance and play, the Polygon is far less inclined to do the latter. This is a bike that causes rocks to jump out of the way and roots to shrivel back into the ground like frightened worms, but don't mistake that for lack of character like I did during my first few times on the Square One. It's the opposite, actually, as this bike has the most personality of anything I've ever ridden. It's just that its personality isn't one that gelled with me. To get right to the point, I can honestly say that I had less fun on the Polygon than I have on other machines. I suspect that going for a joyride in the Killdozer would be fun for awhile, but smashing through buildings must surely get old after you've gone through a dozen or so; the same applies to the Polygon.
If you're familiar with my feedback on bikes, you'll likely already know that I value a lively, playful rig over one that rewards all-out speed, and that doesn't make me a great candidate for the Polygon - I'd need to totally change my riding style in order to get the most out of the bike. Actually, the Polygon and its R3ACT suspension are so different, in both good and less good ways, that I believe most potential EX9 owners would need to do the same. If there were ever a bike that rewarded a balls out, straight line, heels down approach to a trail, it's the big Polygon. And despite the bike's incredible pedaling efficiency, I don't believe that it's the right machine for copious amounts of relatively tame terrain - this isn't the "one bike" that some have said it can be - but then I could also say the same of almost any long-travel all-mountain sled, couldn't I?
This Polygon has to be one of the most charismatic and contradictory bikes of the last decade, and how it performs matches that description as well. It's a hard bike to pin down given that it pedals with the efficiency of a decent trail bike but possesses downhill rig descending capabilities. In theory, this should make it the mythical 'one bike' that so many cliches are usually attached to, but I don't believe that to be the case with the EX9. Everything has to compromise in one way or another, and the big Polygon's concession is that it's just too much of a blunt smashing tool for me to fall in love with it. But if you're the kind of rider who either has to or wants to pedal to the summit, yet also wants what is essentially a sharp handling downhill bike in disguise, the EX9 might be just the ticket.— Mike Levy
About the Reviewer Stats: Age: 36 • Height: 5'10” • Inseam: 33" • Weight: 160lb • Industry affiliations / sponsors: None • Instagram: killed_by_death Mike Levy spent most of the 90s and early 2000s racing downhill bikes and building ill-considered jumps in the woods of British Columbia before realizing that bikes could also be pedaled for hours on end to get to some pretty cool places. These days he spends most of his time doing exactly that, preferring to ride test bikes way out in the local hills rather than any bike park. Over ten years as a professional mechanic before making the move to Pinkbike means that his enthusiasm for two wheels extends beyond simply riding on them, and his appreciation for all things technical is an attribute that meshes nicely with his role of Technical Editor at Pinkbike.