TESTED: 2024 Polygon Siskiu T6E trail e-bike

Polygon have long been known for delivering high-value bikes in Australia via Bikes Online. The recent updates to many models in their range have been greatly appreciated. We recently tested the Polygon Collosus N8E 160mm travel 29er eMTB, and Ryan praised the balanced ride it had. He's also since tested the Collosus N7 enduro bike, which delivers incredible performance for just $3299. In spring I was sent the new Polygon Siskiu T6E trail eMTB to review, one of two models in Polygon's trail eMTB range.

Photographer: Gerard Lagana
Tester: Mike Blewitt
Riding Experience: Lots of travel to ride, race and explore places by bike
Generally Rides: Factor Lando XC, Trek Fuel EX
Height: 178cm
Weight: 72kg
Bike Test Track: Brisbane trails

As part of the Siskiu T (trail) line up, the T6E is a 29er trail bike, with 150mm fork travel and 140mm of rear wheel travel. Polygon use a Shimano EP600 system for the bike, with a full 85Nm of torque and E-tube customisation options, powered by a 504Wh battery. With a Shimano Deore 11-speed group set, SRAM Code brakes and SR Suntour suspension, the T6E sells for $5499 – an incredible price for the bike you get. If you're after a higher-end build, the Siskiu T7E uses the same frame, but has the EP801 motor. This has the same 85Nm of torque but a higher 600W peak power (compared to 500W) plus it's about 300g lighter and has a 630Wh battery. You'll also get 12-speed Shimano SLX and higher quality SR Suntour suspension units, all for $6599.

Polygon are just about playing in their own space with the Siskiu eMTB range. Giant sell the Stance E+ for $6299 although it is shorter travel with less torque, more battery power and therefore range. Trek's Rail 5 is longer travel with 12-speed components, but has a similar output via a Bosch system, for $7499. perhaps the closest competition comes from Marin, also sold by Bikes Online. The Rift Zone E is a 140mm travel trail bike using Shimano EP6, plus a 10 speed Deore group set. It sells for $6499. Polygon call the Siskiu T6E a playful shredder. It hits a very sharp price and looks to have the bases covered in terms of pedal support and features.

Initial Impressions with the Polygon Siskiu T6E

Like any bike from Bikes Online, the Polygon Siskiu T6E was delivered to my front gate by a friendly courier. As a direct to consumer business, you buy your bike via the Bikes Online website. This means you choose your size, any accessories, pay your money and away you go. Given this means your opportunity to test ride is not the same as at your local bike shop, Bikes Online do have a 30 day free returns policy if you unbox the bike and realise it's not for you. More details are on their website.

I have tested a number of bikes from Bikes Online, and I think this was the easiest to build yet, and none have been hard. I put the handlebars in the stem, the dropper lever on the bars and plugged in the EP600 controller and head unit. The Polygon comes with the tools required plus some alloy platform pedals – although I fitted my own clipless trail pedals. All I had to do was set up the cockpit, saddle height, tyre and shock pressure and then plug the EP600 system in to charge, which takes about 4 hours from flat. The bike weighed 24.73kg including the XT trail pedals, so 24.3kg without.

The Siskiu T6E comes stock as a 29er, however a different shock mount location on the link allows a High or Low setting. The Siskiu T6E ships in Low, but High should be used if you opt to put a 27.5” rear wheel in for a mullet setup to maintain bottom bracket height and pedal clearance. 

In the stock Low geometry setting, our large test bike has a 485mm reach with a 65 degree head angle and steep 77 degree seat angle. The chain stay is a reasonably short 445m, which is quite impressive for an eMTB, and should lead to a balanced ride. As the shock is in the middle of the triangle only the 425mL Polygon bottles will fit in the provided cage.

To deliver an eMTB at $5499 does involve some smart parts choices, and one of those is the SR Suntour suspension. The 35mm legged Zeron RC fork uses an air spring and has rebound adjustment and lock out. I found the rebound damping quite effective, and the air spring makes getting it setup for your own riding very precise – you just need a good shock pump. For the rear shock the same applies, although the lockout is replaced with a compression damping adjustment that firms it up, but doesn't lock it out. Given I rarely reach for a lock out on an eMTB this shouldn't pose a problem.

The Shimano 11-speed Deore group set has a wide 11-51t range and combine with SRAM Code R 4-piston brakes and 203mm rotors for all the stopping power you will need. Kudos to Polygon for the 35mm wide Entity rims and 2.6” Schwalbe Hans Dampf tyres with Super Trail casing – these are a truly capable combination in a place where some manufacturers are still choosing options that aren't truly setup for eMTB use.

My first driveway tests on the Siskiu gave a bit of top out from the fork and the back end was pushing into its travel a little more than I expected. I did settle at 90psi and 200psi front and rear before hitting the trails.

On The Trail

The Polygon Siskiu T6E is the first bike I have ridden with Shimano's EP600 motor, which has some slight changes from the EP6 – and I wouldn't have picked that it wasn't their EP800 system as I first set out for a ride. The dynamic Trail setting feels just as supportive, and the Boost setting gives you faster access to up to 500W of power when you need it.

The fit on the T6E was spot on for me, with a 485mm reach paired with a short stem the bars fell exactly where I wanted them to be. The steep 77 degree head angle meant that whirring away up the first climb was a very balanced affair. With a 65 degree head angle stability on descents is assured, but I found thanks to a fairly low head tube the slack front end wasn't unweighted, and didn't wander around on the climb. Polygon should be applauded for speccing 160mm cranks, helping with pedal clearance while keeping the EP6 system buzzing. On the ups I found plenty of traction, the rear suspension is suitably active to keep the rear tyre digging into dirt, but not so much that I bothered increasing the compression damping. I climb seated for the majority of the time on an eMTB unless there are major ledges and step ups, and the suspension was spot on at keeping the traction going to make the most of the assisted ascension.

While the reach number is about right for a modern trail bike in a large, thanks to a modest 445mm chainn stay length and the steep seat angle it translates to a very balanced ride, and this really helps the handling of the bike. It remains maneuverable on the trail while still promising stability at speed and in dicey terrain. The first descent I rode has a fast start with some pedalling, plus a rough chute and a few faster corners that get tighter – a perfect way to get your head around how a bike is handling. The stability that the Siskiu T6E exhibited was fantastic. It is easy to launch into a descent on a bike built to a price point and feel uncertain about the tyres, wheels or suspension. And while I'd had a couple of minor concerns about the SR Suntour fork, this trail showed they weren't needed. Not only did the Siskiu stay the course through fast hits, it easily popped through the corners at the bottom that get increasingly tighter, without wanting to push wide or exhibit any sign of uncertainty through the frame or wheels.

After a few more rides over the coming weeks, I did find on flatter descents I was stalling a little in some tighter corners. While this is mostly a sypmtom of my riding, I had been looking at the option to run the geometry in the High setting. I changed the setting on the shock mount with a 6mm allen key, making the head angle 65.9 degrees, the seat angle steeper at 77.9 degrees, and extending the reach to a huge 495mm while cutting a few millimetres off the chain stay length. Overall it is a subtle weight shift forward, and as I was still finding the back end a bit soft, this also settled that setup as well.

The change was exactly what I was after, suiting my riding and the generally flatter nature of the trails around Brisbane. Sure, we have steep trails too but on the whole the average gradients are pretty mellow. I found no disadvantage for my riding, with the whole bike feeling more agile and fun to move through corners and work through rougher sections of trail.

Around the same time I did jump into the E-tube app and change to the 7 modes of assistance. While I was typically riding in the Trail or Boost setting, this does give more Trail settings, and I find it helped me with a set and forget setting depending on whether I was riding to and from the trails, or doing repeated runs where I wanted a bit more support for steeper climbs.

In terms of equipment on the bike, almost everything blended into the background. The SRAM Code brakes had plenty of power with 203mm rotors, and sintered metal pads as stock. Similarly, the chonky 35mm Entity rims proved to be a perfect match with Schwalbe's Super Trail casing Hans Dampf tyres. This is the second test bike I have ridden with these tyres this year and I'd forgotten how versatile they are. The Shimano Deore 11-speed gearing has a huge range and never missed a beat. While I didn't love the shape of the bars that's a personal fit issue and one I would happily and easily change if the T6E were my own bike. My only main concern was the suspension.

The SR Suntour fork and shock offer plenty of adjustment, thanks to air springs, rebound damping and compression damping units. I did find that if I ran the rebound damping as light as I would like I would get occasional top out. And the rear shock didn't offer the midstroke support I would have liked while still offering a plush feel for trail chatter. It certainly never felt harsh, but it did have a slightly binary feeling of either pushing through lots of the travel, or not. Bear in mind these comparisons are compared to items like a Fox X2 or Fox Performance 34 or 36 GRIP fork, which are commonplace items on eMTBs that cost several thousand dollars more than the Siskiu T6E. At no point did the SR Suntour fork, or shock, prevent me from riding the Siskiu T6E how I wanted to. Given the adjustments available, if the bike were my own I'd look at adding a volume spacer to the rear shock or just fine tuning the pressures further.

Coming into this review I wasn't sure the 504Wh battery was the right choice by Polygon. On hilly rides using Trail and Boost, I was still getting about 2.5 hours of trail time in with battery to spare, and I could use the myriad of Trail settings a lot more to increase that. The upshot is with a smaller battery the bike that stays under 25kg, and is likely perfect for riders who have a few hours of trail time and want to get more descents in when they're on the dirt.

Our Take

It should be no surprise that all of us at AMB have been impressed with the value and quality of Polygon's latest release of bikes. The Siskiu T6E is no exception, and it hits the trail eMTB market with all the features riders should be looking for, at a price that no other brand really can do battle with. This was my first time riding Shimano's EP600 system, while it has the same 85Nm torque as Shimano's top system, I thought the 504Wh battery may prove too small. But it was a great match for the riding time I had available, and the on trail performance of the support system and all componentry didn't leave me wanting. I did feel the damping characteristics of the SR Suntour suspension could use some finesse for those looking to get every bit of performance out of the bike – and Suntour do have their RC2 damper upgrade kit for the fork. This brings in high and low speed compression adjustment and greater overall performance. The rear shock's performance was fine, but spending the time getting the exact setup would prove beneficial.

If some higher performance suspension, or a larger battery is what you're after, then Polygon do have the Siskiu T7E. At $6599 you get higher-end SR Suntour suspension units, a Shimano SLX 12-speed group set, and the biggest upgrade – a Shimano EP801 motor and 630Wh battery. This gives a 100W bump in peak power to 600W, and extra range from the larger battery. Overall I have been thoroughly impressed by the Polygon Siskiu T6E. They have really hit the mark providing the right equipment choices to deliver a versatile full-power trail e-bike at $5500, this is a bike that would suit countless riders looking for an eMTB for trail use and mountain bike fun, with room for some choice upgrades in the future.

Full specs on the Polygon Siskiu T6E

From: BikesOnline
$5499
Weight 24.3kg (as tested)
Available Sizes S, M, L (tested), XL

Frame Material Aluminium
Fork SR Suntour Zeron 35, LO-R, 150mm
Shock SR Suntour Edge Plus RC, 140mm

Motor Shimano EP6, 85Nm
Battery Shimano 504Wh
Display Shimano SC-EN600
Switch Shimano SW-EN600-L

Shifter Shimano Deore 11sp
Derailleur Shimano Deore 11sp
Crank Shimano, 34t, 160mm
Chain KMC X-11
Cassette Shimano Deore 11-51t, 11sp

Hubs Shimano MT400, Boost
Spokes Black, stainless
Rims Entity XL3, 35mm inner
Tyres Schwalbe Hans Dampf EVO Super Trail Speed Grip 29×2.6”
Brakes SRAM Code R, 203/203mm

Stem Entity Expert 35mm
Handlebars Entity Expert 25mm rise, 780mm
Seatpost TranzX, 170mm
Saddle Entity Xtend