Polygon Siskiu NSMB AndrewM.JPG

Polygon Siskiu N9 160mm 29'er Review

Words Andrew Major
Photos Andrew Major (unless noted)
Date Feb 18, 2020

Polygon Siskiu N9

Polygon can't sell bikes based on a storied race history like Yeti, or from being developed with some of the most aggressive riding around in their backyard like Rocky Mountain, or because they have a massive, well established, dealer support network like Trek. Equally, they've chosen not to go the splash-the-cash route by hiring a long list of known riders like other online brands of which YT and Cube are probably the best examples.


Those straight lines come at a cost. Photo - Deniz Merdano

With the Siskiu N9, a bike that would be purchased online by the vast majority of Polygon's potential customers, there is little nuance. It's a long travel, 160mm front & rear to be precise, 29'er Enduro bike that looks pretty damn good and has neutrally-modern geometry. At 2800 USD, it sports an excellent SRAM GX drivetrain, a very well-received Fox rear shock, Schwalbe's Magic Mary tires in a soft compound, a fork with Fox logos on the lowers, and a bunch of other stuff that adds up to create a complete bicycle. Did I mention it's 2800 USD?

Manitou Mezzer (3).JPG

There are a fair few moves I ride on my personal 150mm+ 29er, a Marin Alpine Trail, that I wouldn't hit on the Siskiu N9...

Polygon Siskiu NSMB AndrewM (4).JPG

...but that came down to component choices entirely. The Polygon has amazing potential as longer travel 29er platform.

And, the Siskiu absolutely wants to go. It wants to get deep-deep in its travel, eat bumps, track through corners, and hammer up short, gnarly climbs only to dive back into tight steep rock armouring down the other side. The potential that's unrealized with this bike is both impressive at the price and depressing at the same time.

It's just that it can be a f***ing terrifying prospect trying to reign in those big wheels when the terrain gets steep and deep. Long travel 29ers, like the 160mm Siskiu, need DH brakes and aggressive rubber. Right out of the box. For me that means Schwalbe Super Gravity, Maxxis DoubleDown, WTB Tough Casing, etc. This may be an inflammatory argument, but if a rider doesn't need that much tire, they may not need this much bike.*

Oh, and before we go any further, no, no it does not fit a water bottle in the main triangle. It should, it could, and it doesn't. More on that later.

*One factor here is weight, and at 160-165 lbs, this editor is generally fine on EXO, TCS Light and other mid weight casings - Ed.

The Hot Garbage

I'm not going to dwell on how dangerous the lock-on grips are and how absolutely crotch-murdering uncomfortable the stock saddle on the Siskiu were. And I say "were" because these are absolute throw-away parts. I covered it full throttle in my Siskiu first look. I will reiterate one more time that in the case of the 'ASSault' saddle, no matter how leathery your contact patch or meaty your thigh muscles, you aren't going to want to sit on it or clamp it between your legs. Saddle spec is not hard, if in doubt just follow Rocky Mountain's lead and put a WTB Volt on every mountain bike you sell from $1000 to $11,000+ and at least a significant percentage of your customers will be happy.

Buying a Siskiu? At the bare minimum, budget to replace the contact points straight away.

Polygon NSMB AndrewM (4).JPG

These grips piss me off every time I think about them, especially since a lot of Polygon customers will likely be assembling the bikes themselves. I'd expect any shop would catch the issue but in my experience, this spec choice will put a percentage of their customers at risk of injury.

Polygon Siskiu N9 NSMB AndrewM (5).JPG

I'd challenge anyone who thinks I'm being over-critical of the Entity ASSault saddle to spend a few rides on one. I get personal preference, but I can't imagine a rider who would find it comfortable in any way even with a ham-chamois in their pants.

If The Shoe Fits...

The Siskiu platform fits my 5'9" frame really well, which leads me to classify it as more of a medium-large. As Kenny pointed out in the comments on the first look, that 470mm seat tube is not going to make every rider my height happy. I had plenty of adjustment left with the stock 150mm dropper post and could have run most of the 170mm options on the market.

I managed the shorter Reach and lower Stack of the Polygon versus my personal bikes by running a 20mm wider bar (800mm v. 780mm) with a bit more rise and achieved an excellent, modern fit. I have a good seated position for generating power on flats or climbing and only the steepest uphills had me choking up onto the rivet or standing to hump over the apex.


I was very happy with the fit of the size large Siskiu but it is indicative, with modern geometry, of how necessary it is for companies to add more sizes as the range of optimum stem lengths has really shrunk to 35mm-50mm stems.

When standing in attack position, I had lots of room to move around and never felt like I was fighting the bike in either slow technical or faster descending situations. If I was building a custom frame, it would have a 30mm longer wheelbase which I'd accomplish through slightly longer chainstays, a slacker headtube angle (HTA), and only a touch longer top tube.

In my personal purchase history I have had very mixed experiences with the concept of 'test ride and then decide' when it comes to choosing bikes I love. It usually takes me months to get my rigs working optimally so love at first pedal doesn't necessarily mean happy ever after. Still, I think for a lot of riders it is a good phrase to live and shop by. The Siksiu however, is an internet purchase in most places and that's going to require very carefully comparing geo charts to make the right buy.

Dear Polygon,

You're not alone in the bicycle world by any means, but there are two issues with the Siskiu build that would be easily resolved at your end, are expensive to resolve at my end, and which both point to the fact your product manager either doesn't ride long-travel 29ers or, unfortunately just as likely, chooses not to spec bikes for customers as they would spec them for themselves.

Both come from the fact that this is not a 130mm travel trail bike. The Guide-esque power of the TRP Slate brakes and the unsupportive but relatively grippy Magic Mary tires wouldn't be at all out of place on an aggressive trail bike build, although even in that instance I'd be running bigger than the spec 180mm rotor on the brakes.

Polygon Siskiu NSMB AndrewM (5).JPG

The Slate brakes, as advertised, may be suited to 130mm trail bikes but they have no business being on a 160mm travel 29'er. DH stoppers or don't make the bike is par for this category.

Polygon Siskiu NSMB AndrewM (6).JPG

I'd prefer to see 29 x 2.6" rubber, but even staying with the narrower rubber, the Siskiu is beyond worthy of tires with better sidewall support.

In TRP's defence, they bill the Slate brake as being for 'Trail' usage and Polygon has done them a disservice by selling them on a 160mm travel 29'er. Especially with the mid-sized rotors. Even with TRP's DH level Quadiems I jacked the front rotor up to 203mm and installed some sintered Shimano pads.

Put another way, if Polygon is going to spec TRP brakes then the Quadiems are mandatory on a 160mm travel bike. But, given the full GX build, the Siskiu would be an excellent candidate for the newest Code R brake from SRAM and at the risk of tarnishing my min-maxing reputation I question why they didn't just go full SRAM-duro with a Yari up front, a Super Deluxe in the back, and - yes - a Reverb dropper post.

Polygon NSMB AndrewM (2).JPG

I don't have any issues with TRP rotors but the stock brake pads suck. Non-finned Shimano sintered metal parts are the best answer I've found to maxing performance.

I recognize that I was quite conciliatory to the tire spec in my Siskiu first look but it's either been a long time since I rode Schwalbe' lighter-casing Magic Mary on a long travel bike or Schwalbe has toned down the sidewall support a great deal. I like the Magic Mary, I don't even mind the Soft compound v. the Super Soft, but please give me the support of that Super Gravity sidewall.

One way to improve traction and comfort with a less capable fork spec is to upsize the tires and I think there is a strong argument for a 2.6" Magic Mary on at least the front of this bike. Take that with a grain of salt though as my preference is for Plus or +/- tires but a 2.35 Super Gravity Mary may be your cup of tea.

Mountain Bikers v. Industrial Designers

There is a vocal majority of riders who want the option to carry a bottle inside the front triangle of their frame and those riders are automatically going to scratch the Siskiu off their list because it has no bottle mounts and no room to add them. These folks do not care that industrial designers like the look of straight tubes. They killed Kona's unique looking, and awesome riding, 'Rocker' suspension Process lineup. They mean business.

The Siskiu is a great looking rig, and it wouldn't look as good without the straight downtube, but I'm sure as heck not trading a water bottle for a cosmetic upgrade. I suppose Polygon could contact Trek about licensing KnockBlock but there's a much simpler way to fit a reservoir shock and water bottle into the front triangle with pretty much any suspension design. It's just a bit kinky.

As examples, Guerrilla Gravity and Cotic Bikes both present possible bottle locations that Polygon could R&D that wouldn't require them to change to the Siskiu's vertical shock orientation.

Polygon Siskiu NSMB AndrewM (1).JPG

I didn't care much in the past, but I'm using a water bottle these days and I wouldn't buy a bike that couldn't take one in the front triangle.

Polygon Siskiu Water Bottle NSMB AndrewM.JPG

Guerrilla Gravity and Marin demonstrating mid-sized bottle carrying with a couple of different shock orientations.

I fully support the shock orientation of the Siskiu, mind you. It drives the shock beautifully with no mechanical redirecting of forces and I think there's a strong argument that Polygon could have gone with a less advanced shock than the Fox DPX2, spent the money elsewhere on the build, and still come away with very impressive performing suspension for their price level. I'm thinking RockShox Deluxe here, but there are a number of options that cost less than a DPX2 and are quality shocks.

Going Up

Moving on to the good stuff, the Polygon Siskiu uses its DPX2 rear shock beautifully with a smooth-off-the-top shock activation thanks to the shock orientation. The bike has both premium traction and decent support with the shock wide open without the harshness that can accompany bikes with more obvious anti-squat.

I'm happy to use a Climb Switch for longer uphill efforts, and I certainly did, but if you hate fiddling with knobs but want traction for technical climbs and a buttery ride when descending technical trails then this is actually a tough package to beat.

It's a 160mm 29'er so it doesn't exactly leap forward with every touch of the pedals but I've never ridden a bike that could deliver the best of both worlds with most longer travel machines either feeling a bit harsh off the top or requiring the use of some kind of damper support (Climb Switch / ProPedal / etc) to be rideable up steep grades.

Polygon Siskiu NSMB AndrewM (9).JPG

Traction and support. I regularly used the Siskiu's shock platform for long climbs, but the bike is surprisingly proficient going up with the DPX2 shock wide open considering how plush it is descending.

Climbing out of the saddle, the Siskiu tends to use its travel more freely than other 150mm+ 29'ers I've ridden but I've thrown it out there on a few group rides and I'm apparently in a small minority of folks that care. The DPX2 has three modes for compression and either option other than open made a big difference out of the saddle but not to the extent that it was worth engaging it and losing traction seated in technical climbing situations.

Back to that 75° effective seat angle for a moment. I'm happiest in the 75-76° ballpark on a full-suspension bike so it's no surprise that it worked really well for me. I would like to see every company going to size-specific seat angles that get steeper as they go up in size but until that pipedream becomes reality I hope at least a few companies don't jump on the 77-78° bandwagon for M-L sized frames. I find 75-76° allows power on flats and regular climbs and then bending my elbows and sliding forward on the saddle gives me the extra power I need when the grade is closer to ascending a wall.

Polygon Siskiu N9 NSMB AndrewM (6).JPG

I really have nothing to add to all the ink that's been spilled over SRAM GX. Well, except I wish this was the new 5-spd version. It's the baseline drivetrain against which all SRAM, and maybe even all ShRAMano drivetrains are measured.

Polygon Siskiu N9 NSMB AndrewM (7).JPG

I laughed at DUB 28.99mm cranks too, but the bottom bracket life is killing anything SRAM was doing with 24mm or 30mm spindles. It's a positive improvement for anyone buying an Eagle equipped bike.

I think Cam did a great job of highlighting the GX Eagle package, so I'm going to say it shifted very well in all situations, although I always try not to shift under heavy loads, and I think that, while I'm not creating a lot of black and white over it, it's the highlight of the N9 in terms of presenting value in a 2800 USD bike.

If it was my own bike I'd be investing in a fast-engaging, high quality, rear hub ASAP because that's what I like and I find it makes a big difference to my climbing and technical-gnar riding. For the price, I have no qualms with the wheels other than they didn't come taped for tubeless.

Coming Down

The Fox Rythm fork was okay at best and the brakes were under-gunned even with a 203mm rotor and a significant pad upgrade but the Siskiu's potential still shone through on every ride. If it took a water bottle in the main triangle I'd be all over using it as a test mule because with the right component choices and a 170mm dropper for the steepest stuff, it has the potential to be one of my all-time favourite suspension bikes. And hey, look at all the upcoming reviews it could have been in. For those that don't care about a water bottle, the answer to your next question is no, it is not available as a frame only.

The fork just never felt right, which has been my experience with Fox Rythm product. It was sticky off the top and never seemed to break in. I had an impossible time finding the right air pressure to balance support and bump absorption. Swapping forks doesn't make financial sense, so if this was my bike I would have had the Rhythm serviced and then installed a set of the better Fox/SKF seals that come with their Performance and Factory forks and that would have made a big difference. As it was, out of the box I ran the low-speed compression open all the time, the rebound fairly slow, and the big WTB Vigilante made a significant difference for traction.

Polygon Siskiu NSMB AndrewM (3).JPG

I ended up running PNW Loam grips, my Moon saddle, my P321/Race Face ARC 40 wheel and a 2.8" WTB Vigilante up front and a 2.6 Vigilante in the rear.

Polygon Siskiu NSMB AndrewM (2).JPG

Normally I'd be quite satisfied with a 2.6" tire, but the 2.8" rubber helped make up for the suspension fork's 'meh' performance.

With my litany of 'blahs' all accounted for ,the Siskiu was a capable descending bike but it only truly shined, compared to modern 120mm to 140mm 29'ers I've ridden, in the roughest not-too-steep straightaways or on hits that took me deep into its travel as I was never fully comfortable opening the bike up for fear of not being able to slow it down or get the support I wanted out of the fork without having it feel overly harsh in other trail situations.

And then every once in a while when a solid run-out presented itself, which is less common on the Shore than anywhere else I've ridden, I'd get off the brakes roll into something janky and the rear suspension would squat into its pocket and give me the confidence to ram through a section of trail. And then I'd end up reconsidering how negative I felt about certain elements of the bike.

Polygon Siskiu NSMB AndrewM (11).JPG

Loving all the fresh, and fresher, wood on Boundary Trail. Would love it much more with more aggressive brakes.

Polygon Siskiu NSMB AndrewM (12).JPG

Speaking of, there's a lot of folks riding Boundary these days. If that's you, and you love it, please consider kicking in for some more fresh wood. $2130 raised directly for Boundary to date.

I like the stability of the 440mm stays and combined with the 65.5° HTA the platform is nicely balanced. That's not the same thing as saying I wouldn't love to try an Angleset in there just for sh*ts-and-giggles, but set-up with around 23% sag front and 28-30% sag rear the geometry is Shore-worthy.

Between my setup, the big wheels, and the rear suspension, I found the Siskiu to have a very planted ride, which I like being someone who tends to keep my tires on the ground. It is one of the machines I've ridden lately that has me thinking that for local riding I'd prefer either a shorter-travel 29'er or a similarly-suspended 27+ bike but that's maybe for another article.

Polygon Siskiu NSMB AndrewM (13).JPG

The cables are a bit a mess as the bike was routed British style originally. It would be a very easy to clean up if I had spare TRP brake fittings.

Wrapping Up

I came to a point where I had simply invested all the time I was willing to put into this bike; however, if the rear brake was externally routed I wouldn't have been able to resist a stopper swap because with my Vigilante up-front I think that would be the difference that pushes the Siskiu into being one of the best buys under 3K USD.

There's a bunch of caveats to list from after sale support to getting the bike properly set up at a dealer, etc. But just comparing metal-to-metal with me assembling any bike in my basement, with my knowledge, with my tools, the potential v. price is full show if not full go. Beef up the tires and brakes and service the fork and this is potentially an entirely different review even with having to wear my Camelbak.

Polygon Siskiu NSMB AndrewM.JPG

So. Much. Potential.

I can't recommend the Siskiu without some component swaps and, as it comes out of the box, many riders will be much happier on a shorter travel trail machine with modern geometry numbers. But, at 2800 USD, with a full GX drivetrain, and looking at what else is out there, it's quite possible that a smart home wrench can pick up the Polygon, service the forks with fresh seals, swap to a set of powerful brakes, and install their preferred beefy rubber option and still make out with a lot of bike for the investment. It doesn't measure up to their claim that it's designed to be "ridden in the most demanding of conditions" but it could.

If you'll take that straight-tube aesthetic over a water bottle mount, are handy on the tools, and want to be shifting GX for the least outlay, then the Polygon Siskiu N9 is worth a look.

Related Stories

Trending on NSMB


+2 Andrew Major Pete Roggeman
Rob Gretchen  - Feb. 18, 2020, 6:17 a.m.

I think I am worthy of the Entity ASSault saddle challenge!!    I get teased as I only ride Selle Italia SLR XCs on all my bikes.    Bring it on!!


+1 Rob Gretchen
Andrew Major  - Feb. 18, 2020, 7:04 a.m.

I rode a Ti-railed SLR - no cutout - for years high posting a hardtail and never felt ASSaulted.

That said, I did wear a chamois way back then.


+1 Andrew Major
Rob Gretchen  - Feb. 18, 2020, 7:44 a.m.

What can I say.... it somehow works for this 230lb aSS... Ha ha.....


+2 Pete Roggeman Andrew Major
Merwinn  - Feb. 18, 2020, 8:18 a.m.

Nice wrap up and recommendations needed for a machine that can machine it's straight ahead plowing potential.


+1 Andrew Major
Morgan Heater  - Feb. 18, 2020, 8:51 a.m.

Can you replace the rhythm damper with a grip2 damper?


+1 Pete Roggeman
Andrew Major  - Feb. 18, 2020, 9:49 a.m.

You can absolutely. If I was going to pay for a damper upgrade from Fox it would be FIT4. A bladder-style sealed damper (RockShox, Manitou, Cane Creek, DVO, etc) makes more sense in my experiences. Mind you, I’m not a professional racer (or a racer at all).


Mammal  - Feb. 18, 2020, 9:24 a.m.

Any plans to review the Ripmo AF Andrew?


Andrew Major  - Feb. 18, 2020, 9:51 a.m.

AJ reviewed the Ripmo for NSMB in 2018. I don’t know if there are any plans to review the AF.


+1 Andrew Major
Mammal  - Feb. 18, 2020, 10:04 a.m.

OK, makes sense. With updated geo/leverage and 3K USD starting point including good suspension, I figured it would fit right in with some of these recent lower-price-point reviews. Loving mine so far.


+1 Mammal
Andrew Major  - Feb. 18, 2020, 2:55 p.m.

Definitely, they even pre-min-maxed the suspension spec over drivetrain! Geo looks good.


+1 Andrew Major
Mammal  - Feb. 18, 2020, 5:21 p.m.

Yes, very pleased with the DVO kit so far. Waiting on metallic pads for the the Guide T's for the final verdict, but the brakes may be the only item that needs to be swapped in the end. The 170 KS post it came with works quite well so far.


+1 Mammal
Andrew Major  - Feb. 18, 2020, 6:03 p.m.

Yeah, that’s a beyond lame spec choice that makes you wonder if anyone at Ibis rides those bikes as intended. Same story as the Polygon.

Now you’re on the hook for a pair of brakes where it would have cost almost nothing to get Code R brakes with the bike. Not that they’re my favourite or anything, but there’s no reason to swap out Codes if your bike comes with them.

+1 Andrew Major
Cr4w  - Feb. 18, 2020, 11:24 a.m.

It's like a bad dream remembering when buying a new bike meant getting rid of half of the stock spec because It was so utterly Insufficient for actual riding.


+1 Andrew Major
UFO  - Feb. 18, 2020, 9:58 p.m.

FWIW I was happy with my set of Slate T4s even on the stock red pads, they were better with Shimano metal pads -- think Zee like power with more linear delivery and modulation; better than Guide R and T I've tried in the past.  I had a second set of these brakes come OEM on a bike that was not good at all (especially the front), even with known 'good' pads and a full brake fluid purge and bleed.


Andrew Major  - Feb. 18, 2020, 10:34 p.m.

Not the first time I've heard a similar thing about TRP brakes in general (Quadiems particularly a few folks mentioned it to me). These were just meh and it would be surprising that the QC/QA would be such that there's that much variation - but also not surprising.


UFO  - Feb. 20, 2020, 1:46 p.m.

That's a real odd thing because the systems should be 'simple'. The bad set had a good firm bleed at the levers. Ran pads from my good set so I knew it wasn't issue with the pads. I even swapped the master cylinders around with no change so that would infer that it was a caliper issue. All pistons seemingly extended and retracted with no issues, but there was just no bite.


Please log in to leave a comment.