On Review: Polygon Syncline 9

The Syncline is Polygon’s hardcore hardtail (HT) race machine announced earlier this year at Sea Otter. Using a light, stiff carbon frame, Polygon designed the this bike with race geometry, red carpet components, and years of experience around 27.5-inch wheels, resulting in a fast, snappy, and aggressive XC weapon. Geometry Polygon didn’t throw anything too wild …

polygon syncline 9

The Syncline is Polygon’s hardcore hardtail (HT) race machine announced earlier this year at Sea Otter. Using a light, stiff carbon frame, Polygon designed the this bike with race geometry, red carpet components, and years of experience around 27.5-inch wheels, resulting in a fast, snappy, and aggressive XC weapon.


Polygon didn’t throw anything too wild at the Syncline geometry, as most of its numbers fall in line with other bikes in this class, but there are a few angles and measurements worth mentioning.

Screen Shot 2015-08-23 at 2.41.21 PM
From Polygonbikes.com, size 17.5″ frame tested

At 1,102mm (43.3″), the Syncline has one of the longer wheelbases out there for a 27.5 hardtail*, yet the chainstay measurement is on par with most of the competition at a tight 425mm (16.7″). According to these numbers, 61.5% of the Syncline’s wheelbase is forward of the bottom bracket (677mm front-to-center). This, coupled with its slack (for XC) 69º head tube angle may further enhance the Syncline’s stability when descending steep, technical terrain. For reference, on paper the Syncline’s geometry looks a lot like the Santa Cruz Highball 27.5.


The Syncline is currently offered in four tiered builds (Syncline 5, 7, 8, and 9), and Polygon was generous enough to send me their top-end spec. While the Syncline 9 is as bling as it gets in Polygon’s XC lineup, if you require less than top shelf components or you’re a biker on a budget, models 5-8 are built using the same ACX advanced carbon frame technology, starting around $2,000.

Polygon Syncline

Syncline 9

  • Frame: ACX Advanced carbon frame, 12x142mm
  • Fork: Fox 32 Float Factory Remote with Kashima, 100mm travel, tapered steerer
  • Shifters: Shimano XTR Di2 M9050
  • F/R Derailleur: XTR Di2 M9070/M9050GS
  • F/R Brakes & Levers: XTR M-9000
  • Crankset: XTR M9000 38 x 28 tooth, 170mm (S-M), 175mm (L)
  • Bottom Bracket: Shimano PFBB
  • Chain: XTR HG900
  • Cassette: XTR M9000, 11-40
  • Wheels: XTR M9000, alloy
  • Tires: Schwalbe Racing Ralph, 27.5 x 2.1
  • Saddle: Fizik Tundra 2, manganese rails
  • Seatpost: Ritchey Superlogic carbon, 30.9mm
  • Stem: Superlogic C260 carbon, 90mm
  • Handlebar: Superlogic 2X carbon, 680mm
  • Headseat: Polygon, 42/52 taper, carbon cap

The Syncline 9 is top-to-bottom, front-to-back XTR. Wheels, shifters, brakes, and cranks are all of Shimano’s stunning M9000 series. To top it off, the Syncline 9 is treated with an internally-routed and highly-touted Di2 drivetrain. Although it is an absolute thing of beauty, I remain cautiously optimistic of any battery-powered digital device hitching a ride.

Internally routed XTR Di2 cables

Outside the road bike market I’m not at all familiar with Ritchey components, but I can tell you this stuff looks mean! The beefy Superlogic stem wraps 260º around the bar before bolting the face plate, which claims to deliver increased stiffness and strength without added weight. Feeling out the rest of the cockpit, I found to my surprise the welcomed girth of a 30.9mm seat post (also Ritchey carbon) bolted to one of my all time favorite saddles: the Fizik Tundra 2. 

Polygon Syncline
Shimano Di2 display tucked neatly within the Ritchey Superlogic cockpit. Fox’s dual-triggered CTD remote to rider’s right.

Fox takes care of the squish up front with a 32mm-stanchion, 100mm-travel fork equipped with the FIT damper, 15QR thru axle, and a dual trigger actuated remote CTD. For those new to Fox, C = climb, the setting providing the least amount of travel; T = trail, a moderate amount of travel when pedaling through undulating terrain; and D = descend, opening the fork’s full capacity when ripping downhill. The top lever dials in the fork’s position of choice, while the lower lever immediately releases the current position to Descend.

Initial Impressions

For reference, I am 5’8″, 175 pounds, have an average-for-height inseam, and the 17.5″ frame feels spot-on. At 707mm, the standover height is super low, and the ample 422mm of reach gives me a some room to play with when it comes to dialing in the perfect fit.

I’m only a couple short rides into it, but I was immediately surprised at how quickly I was able to shake that awkward new bike feel aboard the Syncline 9. Also instantly apparent was how different the mid-size wheels felt on this bike versus 29er hardtails. There was indeed a quickness in acceleration and ease in maneuverability that a larger wheel size simply cannot offer. These immediate strengths came to fruition during short thrashes in tight woods and in-town trails, so there’s a lot of ground that remains to be covered in order to come to any real conclusions.

While it’s mostly personal preference and a matter of correct fit, I would like to see more XC bikes follow the ways of the shorter stem/longer bar combination. I find the control and stability of a shorter/wider cockpit more advantageous than the subtle edge in climbing prowess and air dynamics from a longer/narrower setup. I think a sweeter spot would be a stock 70mm-ish stem and a bar length equal to or greater than 700mm.


What To Look For

1. How far can the Polygon Syncline be pushed?

Outside of comfort, handling, strengths, weaknesses, and overall performance, inquiring minds want to know how far beyond Polygon’s “XC race” claims can this bike be pushed. I have little doubt the Syncline would be a suitable race bike, but even the most determined racer finds themselves the majority of his/her time training on and enjoying trails beyond the typical XC race terrain.

2. Do 27.5 size wheels belong on XC race bikes?

It will be interesting to see how 27.5-inch wheels fair on a bike designed for XC racing. I rode and raced on 26ers for a couple years before switching to 29ers, which (for me) was a game-changer. I continued to enjoy the performance of 29-inch bikes for the following four years and, since making the conversion last year to 27.5-inch wheels on my burlier trail bike, decided going forward I would equip an XC race bike with nothing less than 29-inch wheels.

3. How dependable is Shimano Di2?

Of upmost importance will be the reliability and durability of Shimano’s Di2 group. Just the thought of having something electronic controlling a portion of the bike that suffers the most wear-and-tear makes me cringe. That said, I was tickled at the automaticity, exactness, and buttery-smooth performance, during a quick tarmac test.

Polygon Syncline

MSRP: $5,699

The Syncline comes in three other builds, starting at $1,949

Reader Queries: What would you like to know about Polygon’s Syncline 9 during my wringing review process?

Polygon Syncline

*Geometry figures were compared with the Giant XTC Advanced, Orbea Alma, Santa Cruz Highball, Pivot LES, and Felt 7Sixty (all size medium).

Related articles

  1. 9point8 Fall Line R is Reportedly the Lightest MTB Dropper Post Available [Review]
  2. On Review: Shimano SH-M200 Enduro Mountain Bike Shoe and Unzen 4 Enduro Hydration Pack
  3. Review: Reynolds R29 All Mountain Wheels
  4. Interbike Review: Specialized Stumpjumper FSR Expert Evo Carbon 29er