Polygon's Square One will be the first bicycle to feature the Naild's R3act rear suspension system, and the reason you need to know about this truly new design is that it rides like no other dual-suspension mountain bike you may have experienced. Big statement? Perhaps, but I have had the opportunity to trace the development of R3act 2 play, the first production version of the design, for three years running, and during that time, I watched some of the sport's heavy hitters scratch their heads in awe after riding the prototypes. More recently, I was given production-ready machines for final evaluation - an experience that made me wish I had not worn the words "groundbreaking" and "revolutionary" into cliches, because I have a proper use for them now. The Square One EX9 we introduce here has 180 millimeters of ultra plush rear suspension, but unless you were told, you wouldn't know that fact until you dropped into a rowdy descent. More about that later.
Where Did R3act Suspension Come From?
Today, we classify trail bikes by the amount of suspension travel that they possess. The reason is simple: as dual-suspension designs gradually progressed from 100 to 170 millimeters, riders either happily or grudgingly accepted a number of compromises between pedaling efficiency and suspension performance. Even with the addition of technological band-aids like anti-squat kinematics, pedal platform switches, remote travel adjustments, lockout levers, inertial controls and reactive electronics, experience has taught us that, at various waypoints, we trade pedaling efficiency for a more technically capable (and heavier) chassis, and we have names for those benchmarks of compromise: cross country, trail, all-mountain, and enduro.
Designer Darrell Voss thinks otherwise. "I don't believe that suspension travel should necessarily be part of that equation," says Voss. "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?" Voss spent the past nine years working on a suspension system that erases nearly every downside of long-travel rear suspension. Heard that before? Yeah, probably from me, among others. Voss, who is a ripper downhiller, wanted an 180-millimeter-travel trail bike that pedaled as well as the best 120 bikes, but with a suspension that could track the ground like his DH machine. It took him a while, but he figured out a way to do it. It's called "R3act" - a tribute to Newton's third law - and it looks like it was derived from part of an alien space vehicle.
|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?—Darrell Voss|
I'll forgive you for not knowing Voss. He's about as enigmatic as a six-foot, seven-inch-tall genius who has a zillion bicycle related patents can be. Soft spoken, he prefers to work behind the curtain, beginning his engineering and design career with Klein Bicycles in the late 80's, which led to a series of design partnerships and manufacturing operations
in Asia that ranged from bicycle construction, to suspension products, key components, and even a magnesium forging facility. Voss's wide range of experience and tenure in the mountain bike world affords him a broader view of the sport. He lives on the vanguard of technology, but he becomes much more animated when the conversation shifts from extolling the virtues of the latest ten-thousand-dollar superbike, to how it may be possible to squeeze all that performance onto one that only costs only five thousand - which is why he founded Naild, and why Naild's first major project was R3act suspension.
R3act is designed to be a complete rear suspension system that Naild plans to sell to bike makers, along with any assistance necessary, to help them integrate it into their own frame designs. Presently, two bike brands have signed on. Polygon, and another well-known brand that will be debuting its version shortly. The basic suspension configuration is adapted to incorporate variations in suspension travel, wheel diameter and frame sizing. The design of the frame's front section, its geometry, components, and the bike's intended use are left to the customer.Why Elevated Chainstays?
Naild's carbon monostay swingarm is simply the most efficient way to provide an ultra-rigid structure that can incorporate the suspension's tubular sliding element. Shut your eyes and think "bicycle" and you will probably imagine a classic double diamond frame, garnished perhaps, with bits that relate to your style of riding. That's what a bike frame is supposed to look like, right? And, if you were making a frame from steel or bamboo, the double diamond design would be the best possible, time-proven way to build it. The addition of long-travel suspension, however, and the availability of engineered materials, like heavily manipulated aluminum or carbon composites, encourage designers like Voss to deviate from accepted fashion in order to solve new engineering challenges in more effective ways.
No Fuss Suspension
And, the Sliding Element?
OK, here's the nerdy part: Voss admits that the basic concept is not new, and sources two bike designs that used sliding elements to help isolate the suspension from pedaling-induced chain tension: Paul Turner's Maverick and the evolution of Yeti's sliding carriage and present sliding column suspension. His version, however, takes the concept further. The heart and soul of his R3act suspension is a large stanchion tube that pivots near the bottom bracket that the monostay swingarm slides on. The stanchion tube is angled precisely to direct chain tension to counter suspension bobbing, and also to provide an "anti-squat" vector that, unlike the present dual-link suspension designs, remains very consistent through the bike's gear range and suspension travel.
Voss' ace in the hole is that the sliding member apparently balances opposing pedaling and suspension forces so well that a small impact can activate the system. That, and the fact that shock damping is reduced to the absolute minimum, allows the R3act system to track rough or uneven the ground with uncanny accuracy.
What that mumbo means to normal people is, you can pedal the bike in or out of the saddle and as hard or as softly as you want, and it will keep the tire hooked up without having to care about or compensate for what the rear suspension is doing. And, it accomplishes that without the need to engage platform levers, use electronics, or employ damping filters.
Voss would be angry if I continued to baptize readers with suspension kinematics and techno-sermons about R3act. He's spent a measure of his life attempting to debunk the hocus pocus that marketing and media hacks have heaped upon a mechanism that he believes should be a simple to operate. "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."
Truth is, that's all there is to it. No rubber bands in the air can, no knobs to fiddle with. In fact, Voss had to work closely with Fox to provide an X2 shock with almost no rebound and compression damping to optimize its performance. After testing, Polygon deemed the shock's platform lever unnecessary and eliminated it entirely. Voss calls it "Ground Tracking" suspension, because the way that R3act uncouples braking and pedaling forces allows the wheel to follow terrain so closely that most riders initially think something has gone wrong back there.
Polygon Team rider Mick Hannah said, "At first, I thought the rear brake wasn't grabbing. If I wanted to slide around, there's just so much more grip available, I had to use more lever to break traction. I found I could brake much later because of it." Indeed, the Polygon stays composed under braking, and it can level just about anything a proper DH bike can - better in situations like braking bumps - and it somehow manages to perform those tasks regardless of speed. Go figure.
|If I wanted to slide around, there's just so much more grip available, I had to use more lever to break traction. I found I could brake much later because of it.—Mick Hannah|
Presently, R3act swingarms are made from carbon, which is probably the best use of that material. To boost stiffness, the monostay structure is intentionally boxy where space or clearance is not a concern, so the large, hollow part lends itself well to carbon composite manufacturing techniques. The shock is driven by an aluminum yoke that pivots on plain bushings. Lateral forces on the swingarm are controlled by an aluminum rocker link near the mid-line of the swingarm that controls braking inputs and counters lateral forces. The sliding element is a large-diameter hard-anodized aluminum tube which pivots on ball bearings inside a pocket, forward of the bottom bracket. There is no spring or damping assembly between the swingarm and the stanchion tube, it is simply a sliding interface that telescopes as the suspension cycles.
Both the rear derailleur housing and brake hose are routed internally through the Boost-width swingarm, and its 12-millimeter quick-engagement through-axle is Voss' own design. Protecting the swingarm's moving bits from weather and mud is an integrated plastic fender, which came in handy during winter testing. Protection is also provided in the form of a thick screw-on plastic bash guard that is intended to ward off rock strikes where the chassis protrudes forward of the bottom bracket housing. The guard was missing from our Polygon test bike, which resulted in an ugly, but only cosmetic impact crater on the corner of the frame. A second, unnamed test bike had the guard installed and suffered similar impacts without damage.
3 Questions: Zendy Meidyawan Renan - Polygon Product manager
Square One EX Geometry
The Square One EX's offset seat tube and unusual bottom bracket support structure give the impression that the chassis has a very slack seat tube angle, but that is not exactly the case. Measured in a straight line through the saddle to the bottom bracket axle, the Polygon's effective seat tube angle is 73.5 degrees with the stock, set-back KS LEV dropper post, and one degree steeper with a conventional zero-offset post in place. Polygon's reluctance to join the steeper is better seat tube movement is its only nod to conservative all-day trail riders. From there, the Square One's chassis reflects contemporary enduro numbers with a generous reach, a sufficiently low bottom bracket good stand-over clearance and a 66-degree head tube angle.
What motivated Polygon to partner with Naild and adopt the R3act Suspension System?
We decided to expand our market internationally, and we wanted to look for something new and innovative. In our mind, we wanted to keep our company progressive. We saw Naild bring in a technology, totally outside of the box - genuinely - which solved the very basic problems that keep happening in the development of suspension technology for bicycles. In the end, Polygon and Naild have the same simple goal which is, to make people happy when they ride
Why did Polygon decide to drop the shock's pedal platform lever?
We found how well the bike suspension system works with all the damping controls being completely open, and with all of the testing we did, there was no single occasion where our test riders thought they needed to switch off or tweak any setup on the shock, on the fly.
Can the Naild system be adapted for aluminum construction?
It has the potential to go that direction. Seeing how this system works - there is so much potential that we can explore, and to bring it to a more affordable level, surely is one of them. How soon? ...Let's say we have several projects with Naild ahead of us.First Impressions:
|It has been a while since I've seen an innovation as relevant to the moment as Naild's R3act suspension system, and the fact that Polygon is the first to launch it, underscores the possibility that Darrell Voss's invention may fall directly into the hands of riders who need it most. The present enduro/all-mountain bike has evolved to the point of near perfection, but at a cost. Its pedaling efficiency, climbing ability, and edgy performance is dependent upon sophisticated suspension, the lightest construction methods and the best drivetrain parts. Here is a suspension system that can deliver better pedaling, superior suspension action, and greater versatility - and it requires no special components - at least for the rear suspension. |
At a moment when the sport is choking on carbon caviar, Voss and Polygon offer a simpler alternative: How about we skip the science class and ride one bike that can do just about anything we'll ever need a mountain bike for? The Square One EX 9 is not perfect, but it's darn close, and it's a first try. R3act suspension, and the bicycles that are built around it, are only going to improve, which is bound to light a fire under the butts of some of Polygon's very conspicuous competitors. Just when we thought that trail bikes couldn't get much better, Voss and company leave the industry with no other option.—RC
Polygon: Hold my beer....
Ugly? yes, but if it makes me faster then my buddies will be the ones looking at the ugly back end of it while I'm up front. No loss there.
My next ride wasn't as flashy, had way better performance and almost zero maintenance.
Wish I would have married her!
Anyway I think it's a solution to a problem that doesn't exist!
Transition = great looking 4 bar
YT = also good looking 4bar
Canyon = much the same again
Specialized = for the most part, sweet looks
Ellsworth = vomit in mouth 4 bar
My initial point is what you have confirmed in your second statement. The IC or VPP moves along an arc through out the travel of the bike.
What is cool/different about this design is: you are basically getting a double action out of the rear suspension. It is moving a lot more dynamically than a regular single pivot based linkage.
"provide an "anti-squat" vector that, unlike the present dual-link suspension designs, remains very consistent through the bike's gear range and suspension travel"
You don't want anti-squat to be consistent through the suspension travel! Ideally it should fall off in the deeper travel, in order to minimize pedal kickback.
Where's the leverage curve? And pedaling is not the only issue with longer travel: there is also bike weight and suspension feel (poppiness). You ignore those for most of the article.
The split seat tube is also a con, limiting seat post insertion.
Undertstanding anti-squat and leverage curves is not mumbo jumbo. It's not even hard to understand. Or at least it wouldn't be if journalists didn't constantly talk circles around it. We're mountain bikers... if we're here reading an article on the internet about a new suspension design, you don't need to play dumb and apologetic with the "nerd" talk. Your audience isn't stupid, go ahead and get technical because that is what actually matters. Designing stuff might be hard, but the measurements are not hard to understand.
It's only taken 20 years but folks are finally starting to realize a bike's characteristics need not be black magic. A bike rides largely as per it's kinematics and geometry...little more, little less. One doesn't have to be an engineer to make this stuff understandable to the layman.
@tigen: Spot on. I like you.
This article is an advertorial. It's disingenuous and Pinkbike should be ashamed for such a blatent sell-out - and we should be ashamed if we continue to read articles without a skeptical eye. Not that this is the first advertorial on the internet, mind you, but it's a particularly ugly one.
This linkage uses all the standard design parameters (anti-squat, anti-rise, motion ratio) in the same way as almost every other suspension system. There's nothing unique about the kinematics here. Nothing that makes it pedal any better than another design with the same anti-squat parameters (which, contrary to Richard Cunningham's nonsense, isn't completely unique, nor is is superior). No reason why it needs less damping or needs "no rubber bands in the air can, no knobs to fiddle with".
I'm sure this linkage can produce a perfectly good bike, but it won't be *because* of this suspension system.
And you're right regarding how the link can't do anything special. It can't. And touting that it's revolutionary because the anti-squat is "stable" is funny too. You can get similar "stability" with the lapierre/radon/etc four bar design. Not that a flat anti-squat curve means that the pedalling behavior is stable, or that it's a good thing. tigen already mentioned that it's better to have anti-squat dropping off outside of the pedalling area of the travel, which I agree with.
So pedal kickback (presumably at X mm of travel) is proportional to the integral of the anti-squat curve (up to X mm)? Can you gentlemen provide some source material? I have been Google searching about this with no results!
On an different point, it is clear that the anti-squat vectors shown on the diagrams labeled "Anti-squat at zero sag" and "Anti-squat at full compression" are not the correct anti-squat vectors or the EX9. Both of these vectors indicate a lesser magnitude than the anti-squat curves plotted on anti-squat chart included in the article. The shown vectors may be anti-rise vectors but they aren't anti-squat vectors.
The only similarity to Tantrums Missing Link suspension I can see is that no platform shock or lockout is needed for general pedal efficiency.
However Tantrums main attribute is the seamless change of geometry adjusted by the resistance when pedaling uphill, while always maintaining an active in suspension. No lockout levers or other manual adjustments needed. No propedal platform. No electronics or inerthia valves.
That being said, it doesn't matter how well the suspension doesn't bob when you have a 37 pound bike with DH casing, super heavy tires on the bike. Thats what all these suspension gimmicks ignore. Wheel and tire choice will have a bigger impact on how well a modern bike climbs than its linkages, no matter how complex.
@mhoshal: I own a Kona Honzo and a Devinci Wilson. I have owned a Knolly Chilcotin, a Ragley Blue Pig, a Norco A-Line, and a Diamondback Overdrive. My wife rides a Giant Cypher (maestro 5.0). The shop I work at sells Yeti, Giant, and Haro. Never in my life have I ever owned a Yeti, although I have had chances to for VERY cheap. Clearly I am not a Yeti fanboy. I simply have had quite a bit of back to back comparison of Yeti to Giant (and others) with very similar shock set ups and on the exact same trail. Giant makes a great bike. I really like DW Link. I was not stating anything about the superiority of one brand over another. Yeti bikes simply have, in my experience, more pedaling platform than the competition. Does that make them better? I let the rider judge that.
Lighten up Francis.
OH, that is so much better!!!1
Also, the "sufficiently low" BB is sky high, and there was no criticism of the seat angle being super slack.
think about it this way: antisquat/progressivity/leverage ratio graphs... these are all static and for-the-most-part two dimensional ...
the key to the design is the ability to balance both the rider's pedal input (graphs above) AND the inertia (acceleration or deceleration) of the rider ... yes it is dynamic and not easy to describe on paper or the web
the current tools of curves and ratios are insufficient to fully describe the design.
In my opinion, the article seems like a conduit to what the marketing people want to say, with no real criticism or informed analysis of the suspension design.
While I'll reserve comment on real world performance until I actually ride or measure one of these up, @naild-it does actually have a valid point about anti-squat curves: the standard 2D anti-squat curves assume the rider isn't moving up and down on the bike whilst pedaling, and that the bike is on flat ground, and that the rear wheel is moving up and down rather than the sprung mass shifting relative to the ground, and that you're in one particular gear. In practice, even in a single gear there would need to be at least a 5-dimensional curve to simultaneously display all of the relevant factors so as to see a true net force in any situation. This is pretty hard to display graphically given that we only have 3 physical dimensions and your computer monitor is 2D. Weagle has made many references to this in the past and dw-link designs don't run at "exactly" 100% anti-squat at the sag point for that reason. Quotation marks because it's never exact anyway.
Note that this does not in any way mean I am somehow defending or complimenting this particular design - skepticism is never unwarranted really - just discussing these particular comments. I will say however that for any 1DOF axle path, there is nothing new here in terms of the physics involved. Using a sliding element instead of a rotating element does not necessarily generate a centre of curvature that is substantially or inherently different or superior. Migration of the CC (as opposed to the IC) coupled with gearing (chainline) and wheelbase are the invariants with regards to pedaling performance, irrespective of the specific IC location or migration. As a result, 2D anti-squat curves are imperfect (ie 100% anti-squat does not actually mean zero bob) but not irrelevant, as relatively small "fudge factors" can be applied to make them about as accurate as they realistically can be given the variable biomechanics of the rider.
Could be wrong.
I assume anti squat when mentioned in general refers to the Instant centre affect, which compares the chain pull line with the mathematical centre of rotation for the swing arms mass. I personally don't feel the Instant centre property is as hugely relevant to mountain bikes as companies like Ellsworth for instance, claim it to be, for the reasons you touched on.
It doesn't take into account inherent mechanical inefficiency built into a linkage through angular force transfer, this being what gives you reduced brake jack and/or a pedal platform built into the linkage. The actual linkage mechanics and force transfer between links can have more effect on how chain pull forces affect antisquat in pedalling than ICT kinematics do IMO. A company can design something with no ICT anti-squat but it may still have chain growth and a mechanical pedal platform to help it pedal well.
I personally believe a linkage should be designed to be as compliant as possible to bump forces, I.e., like a high single pivot and that chain growth anti-squat and proper shock damping make for a much better all round bike, more reliable, faster over bumps and consistent handling, just a pity so many people don't have proper damping with designs like Ctd's check valve instead of shims being commonplace.
Thanks in advance for any info!
So pedal hard, brake hard, no jack or bob, but hit a bump and the swing arm is free to pivot and telescope out of the the way like butter?
Some other useful references are as follows:
For a bigger picture of vehicle dynamics, read Carroll Smith's 'Tune to Win'
Motorbike suspension: Tony Foale's 'Motorcycle Handling and Chassis Design', make sure you get the second edition though (first edition has an error with regards to swingarm mounted idlers).
Also, Dave Weagle's patents are pretty informative, and my patent (US9168977) also has a ton of info in it.
@hmcleay: Many thanks to you as well!
Anyway, your thoughts on this would be welcome.
On the other hand if the bike has no rebound damping how does it behave on jumps? I would certainly not like being launched into the stratosphere after bigger landing.
This line made me think the shock is basically low-speed rebound only, which is what you would adjust for jumps.
It would be good to know more details
As others have mentioned, the Canfield CBF bikes achieve a very similar (flat) anti-squat curve. Even some dw-link bikes like the RFX can get pretty close. The Yeti Switch Infinity bikes have ~100% AS for >50% of the stroke. Depending on pivot placement, some Horst and single-pivot bikes can get reasonably close - the Trek Slash has 105% to 95% AS through its first half of the stroke. So, a flat AS curve doesn't make something revolutionary on its own.
the full dynamic package matters
the non-uniform pedal inputs and the acceleration / deceleration of the rider are the typical killer ...
the full dynamic package of R3act is what makes this ground-tracing system work
Can you talk more about the full dynamic package, explaining what does does differently than other designs on the market?
The bigger issue is that other systems can also produce a flat anti-squat curve, but they choose to not do so. It's detrimental to have high anti-squat deep in the travel. Why create the pedal kick-back that is inherent to anti-squat in a region of the travel where the rider won't be pedaling (it's generally assumed a rider won't be pedaling beyond about 50% travel, as that much travel implies the rider is taking a decent impact, which is done with cranks level).
There's nothing inherently wrong with this design of a sliding element and a rotating link - it's essentially the same as Yeti's Switch Infinity, plus the ability of the slider to rotate a little - but this implementation of the design is sub-optimal. And the article is all hype and no substance.
I'm not on a crusade against this bike, only against advertorials and hype.
his very basic answer was "the more I ride it ... the better it look" ...
Big Kudos to Darrel and the Naild.it team for getting us riders what we deserve ! Proven Ready product !
This is what I have been saying for years, and why I'm skeptical of the recent trends toward lower-travel bikes. MOAR TRAVEL! 160mm+++++!
Yes, it exactly IS the case. If you are over 185cm, en EFFECTIVE seat angle paired with 425mm chainstays will not work for you on steep climbs and this will not be compensated by R3act.
mombat.org/MOMBAT/BikeHistoryPages/Klein.html See the 1989 ad. He used climbing shoes for the better grip of the rubber on the pedal back then....way before 5.10 haha
And frankly I am not so ready to believe that a 30+ pounds looking 180 travel bike pedals uphill better than anything already on the market ... it is an incredible bold statement to make (as bold as calling DW link or VPP "band aids") and it should be supported by some real data ...
There are some things data will tell you, other things it wont.
I've ridden a lot of bikes (skied on a lot of skis) that shouldn't have worked well according to the numbers and conventional wisdom however IRL performed way beyond expectation. "Feel" and "experience" in the field is another matter - Some times you have to try something and experience it first hand before you can have an objective opinion.
I get it though, this is new, and its easy for anyone to be a skeptic. However, at the end of the day, if one hasn't ridden it (this or any design for that matter) it just amounts to "talk". And, talk is cheap.
And not to be unkind but it is hard to trust Pinkbike: it sings the song of revolutionary innovation on average every 3 months!
Curious to swing a leg over it to see what RC is fussing about tho...
I wonder if a pull shock could be thrown in instead of that "sliding bearing", it could open up some valuable space for a water bottle.
The only way i can see it working descent with next to no compression damping is by using less sag and having a very progressive suspension... The sag-part seems to be true with only recommended 25% sag but there are no words about the progressivity.
But, overall its radical inovasion from Polygon. Good job!
Maybe pinkbike has a review soon
This is better than Horste link?
Better than VPP?
I wonder how many bike companies will jump on board ?
"it rides well so who cares how it looks" is a down right ridiculous comment. Do you apply that formula to everything in life?
I guess they have two design teams, one designed their SS and DH bikes and the other one designed this and their AM bike?
As a rider, it looks legit, less bearings and swingarm components than FSR/VPP and the slider is housed well compared to yeti's more exposed version. Shaft size looks substantial and it also looks like the seal head for it uses the BB tool, so disassembly should be a piece of piss. Looks good.
It just seems a little bit confused in the final geo... slack ESA, Not slack enough HA and a high (comparatively) BB, sort of the opposite of what you would expect from a 180mm bike (you would expect that much travel to be like a mini dh rig but one that pedaled wel).
Still super keen to try one if I ever see one in the flesh...
I can't help but think of the Dyson vacuum cleaner guy when I read this.
Wich one you will choose?
Polygon obviously does not know that.
i will test ride )
..can I borrow it next time you're in town? I'll give right back.
Lookn fwrd to see the 'other' companies iteration.