2020 POLYGON SISKIU T8 REVIEW
TESTING THEN UPGRADING A BUDGET-MINDED BIKE
The Polygon Siskiu T series bikes are some of the best looking, affordable dual suspension mountain bikes on the market and we get lots of questions about them. Several months back we actually made a really fun and detailed Budget Bike Shootout where we gave away all five bikes in the test. But that only opened the floodgates to more questions coming in. For this review we wanted to take a look at another model in the Polygon Siskiu line up and take it a step further as we discuss the process of upgrading that bike as you progress as a rider. And now that we’ve had the time to test this bike in its factory spec, upgrade the suspension as a rider would as they progress and grow, it’s time to report our findings and give this bike away as well as the stock Fox suspension it came with and a set of Schwalbe tires!
THE LAB
Available in either a 27.5” 140mm version or the 135mm 29er version that we tested, the Polygon Siskiu T8 retails for $2,299 and comes spec’d with some decent components. This bike will certainly get you out on the trail and having a good time. However, after some initial test rides and group chats, we felt that the stock suspension was really holding the bike back.
The frame is aluminum and utilizes the Faux Bar linkage design, which is a one-piece pivot bridge that reduces the linkage weight and improves stiffness compared to older models. The suspension curve is in the middle of the pack regarding design. It has a linear curve until the end of the travel, where there is a moderate amount of ramp. We conducted no technical analysis, but anti-squat felt moderate, with some bob on pedal force and lower levels of pedal kickback. What stood out most with the OE Fox suspension spec was the harsh feeling to get the shock to open up and absorb that initial hit.
The Siskiu T8 comes with a Fox 34 Rhythm Boost 140mm fork and a Fox Float DPS custom tuned shock with 135mm rear travel. The T8 build also features a Shimano SLX drivetrain, Polygon’s in-house Entity alloy bars and stem, aluminum Entity wheels, a 150mm Tranz-X dropper, and Tektro HD 4 piston brakes, which we didn’t love but will address below. Some Schwalbe Hans Dampf tires provide ample traction and are definitely a nice part of the build.
We can’t discuss the T8 without mentioning the paint. The deep metallic purple with a color changing downtube hints make this bike stand out without being too flashy. The finish is ultra high quality and definitely makes the T8 look like it costs way more than $2300.
On our size large, the head tube angle is 65.5 degrees, reach is 460mm, wheelbase is 1,193.5mm, and the seat tube angle is 76.5 degrees.
THE DIRT
Before we changed anything on the T8, we had a couple riders spend some time on the stock build. As we said above, the bike rode well but had some major issues that we believe stemmed from the rear shock.
On the climbs, the T8 has a slight amount of pedal bob that is solved with a flick of the climb switch. The 65-degree head tube and nice seating position allow the rider to navigate both steep switchbacks and long road climbs comfortably but it’s certainly not a high performance climbing machine. Descending is balanced and the geometry makes the bike feel confident and stable, but we found the end of the suspension very quickly and felt that the rear end was harsh on square-edge hits and roots. We set the suspension up with 28-30% sag, which is usually the sweet spot for our whole test crew, but we could never seem to dial the Siskiou T8 in to balance big hits or high speed chunder.
While the suspension feedback and harshness gave us concern on rough trails, we enjoyed the stability and balanced feel of the Siskiou T8 on faster flow and jump trails. It was here we realized that this bike had the potential to be a lot more, it just felt constrained by the rear shock tune. All of our testers enjoyed jumping, manualing and slashing the bike around, so we reached out to SR Suntour to see if they’d be interested in joining our experiment.
Many times when people upgrade their bikes they feel they need to go all out, or spend a lot of money to get performance gains. Having spent a lot of time on SR Suntour products, we knew that we could get a solid upgrade without spending Factory Kashima money. The theory was that a cost effective SR Suntour Auron fork and TriAir shock would save us hundreds of dollars and still offer better performance than the stock Fox Float dampers and leave us cash to upgrade the brakes, another Achilles heel of the bike.
The change was instantly noticed as we tackled rocks and roots with the SR Suntour TriAir rear shock. We have positively reviewed the Auron and TriAir before and this experience reinforces our suggestions to not discount SR Suntour when it’s time to upgrade your ride. The Auron fork gives a much more supported feel with a proper 30% sag dialed in, kept calm on the rough and reduced our divey 34. No harsh bottom out is felt even when taking it into steep and big terrain. Similarly, the TriAir woke the rear end up, allowing the rear tire to move out of the way of obstacles without that harsh feedback we had with the Fox. The feeling of overdamped rebound to make up for sub-par compression was gone. The TriAir with three volume spacers is the ticket to make the T8 compete with bikes that cost twice as much. It pops off jumps, handles high frequency bumps with ease, and even takes drops without a hiccup.
What would be our next upgrade? The brakes. While the Tektro four-pistons have plenty of power, the levers are reminiscent of 80’s cantilever levers, making lever feel non-existent. On top of that there’s a lot of dead stroke where you’re pulling this big, long lever and nothing happens. We found ourselves riding with the brakes half in just to feel the bite point. While they are rideable, we would most definitely opt for another four-piston trail brake with some more modern levers.
The Wolf’s Last Word
It’s a shame that two major spec choices detract from what could be a really bad ass bike. Don’t get us wrong, for $2,300 the Siskiu T8 is a solid contender in the budget market and it does perform fair, but with bikes from Marin and Canyon having slightly better functioning components at similar price points, these are things we have to point out. That being said, after upgrading that rear shock, riders will have a beast of a bike that’s ready to get rowdy! It has a spec that will let you grow into your skills and even support some serious shredding before you find the limit, but we’d love to see better brake levers and shock tune in the future. It has the geometry to hang with any trail bike out there and a beautiful paint job to have you feeling proud at the trailhead. If you are willing to do a shock upgrade, or don’t live in an area full of roots or sharp rocks and prefer smoother trails or jumps, then this bike could be your new entry to the world of shred. We had fun on this bike and are very pleased that with some easy upgrades we can extend its lifespan as riders grow and push the limits over time. 
Price: $2,299
Website: Polygonbikes.com
SPECIFICATIONS
CHASSIS
Frame: ALX Trail 140mm travel (27.5”) / 135mm travel (29”)
Fork: Fox 34 Rhythm Boost, 150mm (27.5”) / 140mm (29”) Travel
Shock: Fox Float DPS Special Tuning
COCKPIT
Brakes: Tektro HD-M745 4-Piston
Shifter: Shimano SLX
Handlebar: Entity Xpert, Alloy 800mm
Headset: ZS 44/28.6 | ZS 56/40
Stem: Entity Xpert, Alloy 35mm
Saddle: Entity Xtent
Seatpost: Tranz-X 150mm (S-M) 170mm (L-Xl), 30.9mm
WHEELS
Wheelset: Entity Xl2 Disc 27.5″ / 29″
Tires: Schwalbe Hans Dampf Evo 27.5×2.60″ / 29×2.60″
DRIVETRAIN
Bottom Bracket: BSA Threaded
Cassette: Shimano CS-M7100-12 SLX 10-51T
Cranks: Shimano FC-MT510-1 Boost 32T 170mm (S-M)/175mm (L-XL)
Derailleur: Shimano SLX
We Dig
Capable geometry
Playful and confident
Beautiful paint
Fair Value
We Don’t
Shock tune
Brake levers
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