Bike test: Polygon Siskiu T8
From relative obscurity a handful of years back, Indonesian-based Polygon has come charging through the pack to become a definite player in the mountain bike scene. Recently I tested the top-spec carbon Xquareone EX9 and, despite coming from a less well-known brand and its premium price tag, I consider it one of the best, if not the best, bike I’ve ridden to date.
The Xquareone was a ground-up new design, and the same could almost be said about the Siskiu T8 on test. Okay, so the name isn’t new - I rode and reviewed the Siskiu D8 two years ago - but apart from the name, the T8 shares virtually nothing in common with its namesake.
Where the earlier Siskiu D rolled on 27.5-inch wheels, it was dated in its geometry and spec, and was more aimed at the XC side of mountain biking. The new Siskiu T is another beast entirely.
There are two variants of the Siskiu T; the entry level T7 costs $2299, while our more premium offering, the T8, is priced at $2999. Both share the same 6061 aluminium frame, the same wheels and the same dropper post; both also run a 1x drivetrain. However, the T7 uses a 10-speed set-up, compared to the 11 speeds on offer with the T8.
The geometry of the Siskiu T8 is quite modern without being extreme. Our size Large test bike has a reach of 450mm, fairly short 435mm chainstays, a low 337mm bottom bracket height, and a decidedly slack head angle of 66.5 degress. Polygon has also gone for a scaled approach to wheel sizing, with Small and Medium bikes shod with 27.5-inch wheels, while Medium (as an option), Large and XL bikes come with 29-inch hoops.
This concept isn’t new, of course, but it does mean that the wheel size is more proportional to rider height, which helps to keep ride feel consistent across all sizes… and if you fit a medium you get to choose which way you want to roll!
Travel-wise, the Siskiu 27.5 offers 150mm of squish front and rear, while the 29-incher loses 10mm at both ends.
Put that all together and it’s clear that the new Siskiu has completely shed its XC heritage and is very much intended as a rowdy trail bike, able to hold its own with longer-travel rigs in the rough while not feeling overgunned when distances are long and the trails are groomed.
In the Stand
Polygon has obviously put a lot of thought into the aesthetics of the Siskiu T8, and I think it’s hit the nail squarely on the head. The matte black frame with its orange and turquise highlights looks classy and understated. The lines are clean and the frame build looks beefy and ready to rumble. Welds aren’t quite as clean as on some other bikes I’ve seen, but they’re certainly not terrible, and it’s also nice to see solid pivot points with laser etched torque values on them, too.
The internal routing for the shifter cable and dropper post are tidy, but the ports are tiny and will make future cable changes a bit of a nightmare. ISCG tabs are present for those of you who want to run a chainguide, and the threaded bottom bracket will keep mechanics happy. The direct-mount rear derailleur hanger helps keep shifting precise - but it does mean you’ll be stuck with Shimano - and there are no water bottle mounts at all so you’ll always need to carry fluids on your body somewhere.
Polygon has imbued the Siskiu with plenty of tyre clearance, even with the 2.35-inch Schwalbe tyres fitted as standard, so you’ll be able to experiment with semi-fat 2.6-inch tyres should you so desire.
It’s wonderful to see a set of wheels with a 29mm inner width fitted by Polygon, too; wide rims and wide tyres are definitely the way to roll, and the rims can be converted to tubeless with a bit of tape and sealant. It’s also unusual – and welcome - to see Schwalbe’s top tier casing and rubber on a bike at this price.
The 780mm handlebar and short 50mm stem speak to the intentions of the Siskiu T8 as a descender, although I did find the bar a little flat and straight for my tastes; I prefer more sweep to take pressure off my old and damaged wrists, especially on a wider bar. The non-series Shimano brakes worked reliably; however, they did lack a bit of overall bite. Bigger rotors and/or better pads are a recommended upgrade down the way if you ride in steep terrain.
And then we come to the sliding bits; the dropper seatpost and suspension. It’s great to see a 150mm dropper post on a bike at this price (even the T7 gets the same dropper); there’s no excuse for a modern mountain bike, especially in a larger size, to have any less drop than this.
The Rockshox Deluxe shock is an excellent and proven performer and, given that you’ll often see the same shock on bike three times the price of the Siskiu T8, the Polygon team has chosen wisely. Likewise with the fork, the Rockshox Revelation might use the simpler Motion Control damper, but the chassis is the same as the highly regarded Pike, and there’s precious little difference in performance between these two stablemates.
I have to hand it to the Polygon design team; they’ve designed a very good looking bike with modern geometry, and have spent their money wisely when it comes to the parts hung from it. The Sub-$3K pricepoint has always been hotly contested; it’s where many buyers will shop for their first serious mountain bike, and bikes at this price have to perform reliably on the trail while foregoing all the bling parts and their associated price.
Going up against established heavyweights like Giant’s Trance 3, Trek’s Fuel EX7, the Specialized Camber and even the Canyon Spectral 6 is no easy task, but the Siskiu T8 is a very, very strong contender indeed, and in many ways is the pick of this bunch.
On the Trail
Not so long ago cheaper mountain bikes used to feel cheap, but not so with this latest Polygon. The thing that struck me about the Siskiu T8 almost immediately is just how much it feels like a much more expensive bike; it’s an incredibly neutral and intuitive beast to ride, with no learning curve or weird handling traits at all. Set sag (30 per cent rear, 22 per cent front) and rebound, and hit trails; that’s it. It pedals surprisingly efficiently even with the shock fully open, and it responds quite enthusiastically to pedal input.
On steep climbs the Siskiu sits quite deep into the rear travel which makes it light on the front end, so I deferred to the middle shock setting most of the time when I wasn’t pointed downhill. Pedal kickback is noticeable especially on square-edged steps, so some finesse is required to clean tricky climbs if you’re not clipped in. It’s not a deal breaker by any means, and no worse than a lot of other bikes on the market.
The bottom bracket height is very much at the low end of the spectrum, so I suffered a lot more pedal strikes than usual when climbing on the Siskiu T8; the trade off is in better handling through corners and more stability at speed.
In the open setting, the rear suspension strikes a good balance between suppleness and support; it doesn’t feel harsh at all, but it doesn’t use travel unnecessarily, either. The overall suspension feel is linear and progressive; in general trail riding situations it’ll rarely use the last 15-20 per cent of the shock’s stroke, and it’s only when you start hitting drops or gaps that you’ll see the travel indicator pushed to the end of the shaft. If you were hitting downhill lines regularly you might want to add a volume reducer, but otherwise the rear suspension is pretty much sorted straight out of the box.
At the other end of the bike I found the two air volume reducer tokens fitted to the fork made it almost impossible to access the full 140mm of travel, and I’d probably recommend removing at least one of them. Otherwise, the Revelation does a very good job of matching the performance of the back end, and in all but the most extreme (for this bike) or extended descents would you be able to pick a difference between it and the pricier Pike.
The only other point to note about the suspension is the slight amount of stiffening under brakes. This is common to most linkage-driven single pivot bikes, and you do get used to it quickly, but you can’t just come screaming into a corner full of braking ruts, grab a fistful of brake and expect to pull up smoothly.
Some might question why Polygon didn’t go with a Horst Link style of rear suspension (fitting a pivot at the rear of the chainstays) now that the patent has expired, but the advent of single ring drivetrains has made it easier to optimise the performance of a single pivot, and having one less moving part between the cranks and the rear axle makes for an inherently stiffer rear triangle. Swings and roundabouts…
It’s worth noting that the geometry of the Siskiu feels just about perfectly balanced for an all rounder mountain bike; it’s spacious enough for extended climbing, whippy enough for tight trails and stable enough to feel confident on the steep and relatively gnarly stuff. It corners very predictably, no doubt helped by the low bottom bracket, and it’s plenty stiff enough to track wherever you point it. It may well be a budget bike, but it certainly doesn’t feel like one once you get it rolling.
Polygon is like the musician who spends 10 years playing in pubs and clubs before becoming an “overnight” success. For 25 years Polygon has put in the hard yards, and suddenly the company has hit its stride. And everyone should sit up and take notice.
The Siskiu T8 comes in at a price that is very much at the entry level of the mountain bike spectrum, yet despite some budget parts it has no obvious chinks in its armour. It’s not perfect (see sidenote), but it looks good, it’s generally well built, has great geometry, excellent suspension, a good mix of totally functional parts, and there’s really nothing more you need to spend on it in order to get out on the trails.
Polygon blew my mind with the XQUAREONE, redefining the notion of the most capable mountain bike on the planet. Now it’s done the same thing with the Siskiu T8; it’s arguably the best performing bike on the market for the price, and probably better than a lot of bikes costing $1000 more. If you’re looking for a genuine, do-it-all mountain bike on a modest budget, this deserves to be at the top of your wish list.
MBA Extra: Cost cutters
In order to get such a great performer so well specced at this price, any manufacturer is going to have to cut corners somewhere. Cheaper parts are frequently made to lower tolerances, or from cheaper materials, or simpler designs, and there are a few parts I had issues with on account of this.
Firstly, the Tranz X dropper post kept losing air and needed to be pumped up before every ride. I know of other people who’ve had no issues with these posts, so likely this one was a Friday afternoon special.
Secondly, the upper headset bearing was so loose in the cup that no amount of tension on the star nut could stop it from knocking, and I had to fix it (temporarily) by wrapping electrical tape around the bearing before refitting it.
Lastly, the rear hub made a few pinging noises over the course of the test period. It never failed, but I’m no wattage monster, and strange noises from a freehub usually don’t bode well for longevity.
Of course all of these issues will be covered under warranty (a year on parts and five yeaers on the frame), but you’ll need to send it back to Polygon or go to one of the brand’s appointed service centres for a fix . Lower prices can come at the cost of service convenience; whether this trade-off is worthwhile is a question only you can answer.
NAME Steven Hinchliffe
RIDING STYLE Tech up and down, and flat pedals all the way
HOME TRAIL Southern Illawarra NSW
SIZE TESTED L
SUSPENSION PRESSURES 55PSI (full open rebound, 2 tokens on Revelation RC), 130PSI (full open rebound, RS Deluxe)
TYRE PRESSURES 25psi/22psi (f/r)
Excellent all-round geometry
Outstanding value for money
locked into shimano drivetrain
In the stand 8
On the trail 7.5