Polygon Siskiu T8 Review

Should I Buy This Bike?

The 2021 Siskiu T8 is an impressively well-rounded mid-travel trail bike offered at a very competitive price. Polygon is a consumer-direct brand, and their bikes are sold and distributed by BikesOnline.com in the US. Polygon can offer a price-to-build ratio that only fellow consumer-direct brands can compete with, thanks to the consumer-direct sales model. That said, the components on the Siskiu T8 are just one of the reasons this bike performs so well on the trail. The 2021 Siskiu T models have a completely redesigned frame with several improvements and geometry tweaks that align with all the modern geometry trends. It may look a lot like the previous version, but suspension kinematics have been tweaked slightly, and it was given a healthy dose of the long and slack treatment. It is still a versatile ride that performs well in all situations, but now it feels more confident and composed at speed and in steep, rough terrain. Despite the recent updates, it retains the responsiveness, agility, and playful demeanor that were the hallmarks of the previous version. Our testers were thoroughly impressed with the Siskiu T8, and we feel it is an excellent, do it all, mid-travel trail bike for the rider on a budget. You could always upgrade with more expensive bike components, but we were happy to ride it out of the box.

Fun Factor

The Siskiu T8 proved to be a blast on the trail. Fortunately, Bikesonline.com has a very user-friendly unboxing process, and we had the T8 ready to roll in about 30 minutes with no adjustments to the drivetrain or brakes. Tools were included, and the process was very simple, so we could get on the trail and start having fun. We felt comfortable when we threw a leg over our test bike. It was intuitive and felt like meeting up with an old friend. There was no awkward getting used to it, period; it was just game on from the start.

One of the things we liked so much about the Siskiu T8 was how natural it felt. Climbing or descending, high or low speeds, it just felt right. The 135/140mm of rear/front travel is ideal for many riders and locations. It's that perfect middle ground that's still lively and efficient, but it has your back when things get rough and nasty. The updated geometry also does wonders for this bike's descending prowess. It still feels relatively nimble and responsive but doesn't falter when speeds increase or flinch when the trail gets steep and rocky. At the same time, it climbs like a goat with loads of traction, responsive handling, and a steep seat tube for direct and efficient power transfer. It's not the most playful nor the hardest charging bike we tested, but we find the versatility, well-rounded performance, and user-friendliness of the Siskiu T8 to be loads of fun.

Downhill Performance

Compared to the previous version, the new Siskiu T8 is more capable and confidence-inspiring on the descent. This is due mostly to the updated geometry, which includes a longer reach, wheelbase, and slacker head tube angle. Minor changes to the rear suspension adjust its kinematics and performance. While we liked the previous Siskiu T8, we feel the recent updates have helped make it a more well-rounded and competent descender.

When Polygon redesigned the Siskiu models, they gave the frame a serious overhaul that brought it in line with today's modern trail bike geometry "standards." This includes extending the reach by 25-30mm across all sizes, up to a roomy 480mm in the size Large we tested. The head tube angle has also been slackened by a full degree to 65.5 degrees. The extended reach and slacker headtube resulted in a longer wheelbase, now 1220mm on the size Large. The added length of both the wheelbase and reach has done wonders for this bike's stability at speed, and the slacker headtube helps make it feel more confident when dropping down steep or chunky sections of the trail. One might think that the added length or slackness might make the Siskiu feel more sluggish or less agile in tight terrain, but we didn't find that to be the case. The 430mm chainstays are relatively short for a 29er and help to keep the rear end of this bike feeling sporty and easily maneuverable. We wouldn't say it's the poppiest or most playful bike we've tested, but it still had us looking for side hits and trying to manually every trail dip.

The Siskiu T8 has a Faux Bar suspension design and a linkage-driven single pivot. The main pivot is on the seat tube a couple of inches above the bottom bracket. The pivots on the seat stay just above the rear axle, and it has a one-piece rocker link attached about midway up the seat tube. The one-piece rocker link is claimed to add rigidity and lateral stiffness, and it directly drives the seat stays to compress the rear shock. Adjustments to the suspension design have supposedly resulted in increased anti-squat for improved pedaling performance. The Fox Float DPS shock also comes with a light custom tune to make it supple in the initial part of the stroke and have a more linear curve. We found the suspension to feel quite supple over small and mid-size chop and chatter, and there was still enough progression towards the end of the stroke to prevent harsh bottoms outs on larger hits. Anyone seeking more ramp-up at the end of the stroke can easily add volume spacers to the rear shock.

The component specification of the Siskiu T8 works quite well and helps improve its downhill performance. The Fox Rhythm 34 is a very nice fork for a bike in this price range, and it easily outperforms cheaper forks on the competition. The 780mm wide handlebar and short stem provide great leverage for responsive handling, while the Tektro 4-piston brakes worked way better than we expected. The drifty feel of the Schwalbe Hans Dampf tires takes a little getting used to, but they work well in a huge range of conditions, and their 2.6-inch width has loads of air volume and a huge contact patch resulting in excellent braking and cornering traction.

Climbing Performance

The Siskiu T8 is a competent climber with comfortable geometry and loads of traction. At 32 lbs 8 oz (set up tubeless without pedals), it's not the lightest weight or zippiest feeling on the uphills, but it's certainly no slouch. It performs well in tight, technical terrain and long, steep grinds. The quality component spec, specifically the drivetrain, and tires, helps bolster its solid climbing performance.

Following recent trends in mountain bike geometry, Polygon steepened the effective seat tube angle on the Siskiu T8 to 76.5 degrees. This lines the rider above the bottom bracket for a direct and efficient power transfer down into the pedals. The steep seat tube also makes the bike's longer reach feel slightly shorter, resulting in a comfortable, relaxed seated pedaling position. The increased anti-squat of the rear suspension also helps keep the rider propped up, and it doesn't settle too deep in its travel while climbing. Despite the slack-ish 65.5-degree head tube angle and a 1220mm wheelbase, the reduced offset fork helps keep steering and handling from feeling vague. Testers found the Siskiu to negotiate technical terrain with relative ease.

The Faux Bar rear suspension platform has a nice active feel when climbing, and it smoothes over small bumps and trail chatter and helps maintain excellent traction, especially when seated. Out-of-the-saddle efforts did result in noticeable pedal bob, but no worse than most other bikes in this test. Fortunately, the Fox DPS Performance rear shock has a 3-position compression damping/climb switch to help stiffen up the suspension should you choose. Testers mostly rode in the open position but occasionally would switch to the middle position on longer climbs for a slight improvement in efficiency. The firm position came in handy for extended pavement or fire road climbs; we feel it's a nice option.

The Shimano SLX 12-speed drivetrain worked flawlessly for us during testing with crisp and precise shifting. We feel it performs much better than SRAM's low-end offerings that are common on other bikes in this price range. A 32-tooth chainring is paired with a 10-51-tooth cassette for a massive range that we found to be adequate for any steepness of hill we encountered. The big ol' 2.6-inch Schwalbe Hans Dampf tires have excellent climbing traction and hook up well in most conditions and surfaces.

Build

The Siskiu T8 frame is constructed of ALX Alloy, and it has clean lines and a stunning paint job. It comes with size-specific wheel sizes, the Large and Extra Large frames come with 29-inch wheels, the Small comes with 27.5-inch wheels, and the Medium can be purchased with either wheel size. The 29-inch wheeled versions have 135mm of rear-wheel travel and a 140mm fork, while the 27.5-inch versions have 140mm of rear travel and a 150mm fork. The frame has internal cable routing, integrated chainstay protection, and room in the front triangle for a full-size water bottle. Attached to the frame is one of the nicest builds you'll find on a bike in this price range.

Polygon has equipped the Siskiu T8 with a quality Fox suspension package that is quite impressive for the price. A Fox Rhythm 34 fork handles the 140mm front suspension in a smooth and controlled manner. The 34mm stanchions and the FitGrip damper are perfect for a mid-travel trail bike like the Siskiu, and the Rhythm 34 works well without being overly complicated. A Fox Float DPS Performance shock controls the rear travel with a custom tune, rebound adjustment, and a 3-position compression damping/climbing switch.

The Siskiu T8 is clad with several Polygon's house brand components, known as Entity, including a set of Entity XL2 tubeless-ready wheels. The rims have a 35mm internal width and pair well with the 2.6-inch wide Schwalbe Hans Dampf Addix Speedgrip tires. The Hans Dampf is a great do-it-all trail riding tire known for its somewhat drifty feel and versatility. The tires come set up with tubes, but both the wheels and tires are tubeless-ready and can be converted to tubeless in just a few minutes (and about $30) with the purchase of some tubeless valve stems and sealant.

The cockpit of the Siskiu T8 comprises mostly Entity branded components. It is generally pretty dialed, but we did take issue with a couple of things. The 780mm wide handlebar is clamped to a short, stout 35mm stem with a 35mm clamp diameter. This bar stem combo was nice and comfortable and provided a direct, responsive handling feel. A set of Entity lock-on grips are attached to the handlebar, which we found to feel a bit on the thin and firm side for our tastes. At the bike's rear, a 170mm Tranz-X dropper (S and M frames come with 150mm) gets the saddle down and out of the way on descents. On top of that post is an Entity XTENT saddle. While cool looking, we found the Entity saddle to be a bit short, and the oddly shaped points at the rear were prone to jabbing us in the pelvis on steep descents.

Polygon didn't mess around with the drivetrain on the Siskiu T8. The 12-speed Shimano SLX shifter, derailleur, and cassette create a drivetrain system that works incredibly well. The Shimano alloy cranks come with a 32-tooth chainring that pairs with the 10-51-tooth cassette to provide ample range for whatever comes your way. A set of Tektro HD-M745 4-piston hydraulic disc brakes with 180mm rotors handle the stopping duties, and we were quite impressed by how powerful they felt. The brake levers, however, had a long throw and relatively cheap look and feel.

Value

We feel the Siskiu T8 is a great value. This bike brings an excellent price-to-performance ratio and is one of the nicest builds you'll find on a bike at this price. Not only were we impressed by its well-rounded trail manners, but the parts attached to this bike work very well and won't have you reach for your wallet to upgrade anything immediately. It also comes with a set of decent flat pedals with adjustable pins, so you won't have to spend money on pedals if you don't already have some.

Conclusion