Transition Sentinel Alloy - 19

Transition Sentinel Alloy - 19
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2019 Transition Sentinel Alloy

Designing a bike, or even deciding on which bike to buy, can be a series of frustrating trade-offs: durability for weight, stability for agility. And that conundrum of choices perhaps is never more apparent than when choosing the right downhill thrasher for you. The Transition Sentinel aims to give you the best of all worlds with a long travel 29er that actually climbs as effectively as it descends.

Transition claim that they want the Sentinel to convert, or perhaps reconvert all you thrashers out there to the notion that a 29er with tons of travel can be more than just a DH tank. We are thinking that there aren’t that many folks out there who hate 29ers, but just need to know that it will be as versatile as every trail rider likes. The brilliant thing is that Transition have designed a bike that looks to be at the forefront of a new movement. With their Speed Balanced Geometry, referred to by the snappy acronym SBG, Transition have figured out how to balance the ultra-long reach and slack head angle with the need to be able to maneuver the bike over tight trails. They manage this because the SBG lengthens the wheelbase while reducing the offset of the fork and shortening the stem. That combined with the steep seat tube angle means that the rider will be in a great position for climbing. And the Sentinel has the kind of rollover that will help you crawl up anything that isn’t actually vertical.

But most importantly, the SBG guarantees the type of playful downhill ride that will keep a huge smile on your face and encourage you to push yourself that much more because you will always feel well balanced and in control. Combining the geometry with the Transition GiddyUp 2.0 suspension design will give the sort of plush ride that will make the 140mm of travel seem bottomless. And with 160mm fork up front, you’ll be able to handle some big drops without suffering bobblehead syndrome. The durability that the aluminum frame offers will encourage you to take those jumps and huck big gaps. And since the frame will accept tire widths up to 2.5 inches, you can count on being able to have a setup that will offer tons of grip and traction.

In fact, as fun as this design is, they never veer away from the practical solutions in favor of bling. So you will get internal, rattle-free cable routing through the main triangle, while the rear brake line is exposed, facilitating an adjustments required. Similarly, the bottom bracket sticks with the tried and true threading, making it much easier to maintain and increasing the overall durability of the frame. Then the ISCG05 tabs will mean you can install a chain guide, but be aware the Sentinel supports only 1X groupsets since there is no front derailleur mount. For anyone who likes to run longer dropper posts, you’ll be pleased that the seat tube is quite high, while there is plenty of standover height. Boost spacing will mean you can run some mega wheels to cope with the toughest runs.

With the stability on the downhills and the agility on the uphills, you can feel excited about the way the Transition Sentinel mixes top performance with high-spirited playfulness.

  • Frame: Alloy
  • Rear Triangle: Alloy
  • Suspension: GiddyUp 2.0HH
  • Rear Shock Size: 205mm x 57.5mm
  • Shock Option(s): Fox DPX2 Performance Elite
  • Rear Travel: 140mm
  • Shock SAG: 32-35%%
  • Fork Travel Range: 160mm
  • Head Tube Diameter Top: 44mm
  • Head Tube Diameter Bottom: 56mm
  • Headset Included: No
  • Bottom Bracket Type: 73mm | Mountain Threaded
  • ISCG Tabs: ISCG05
  • Cable Routing Brake: External
  • Cable Routing Shifter: Internal
  • Cable Routing Dropper Seatpost: Internal
  • Front Derailleur Mount: N/A
  • Wheel Size: 29”
  • Max Tire Size: 2.5”
  • Brake Mount Type: Post mount, 180mm
  • Seatpost Diameter: 31.6mm
  • Seat Collar Included: Yes
  • Rear Axle: 12mm Thru x 148mm BOOST
  • Sizes: 14.2” SM | 15.75” MD | 17.3” LG | 19.3” XL | 20” XXL |
  • Colors: Gunmetal Gray, Pinot Noir
  • Weight: 4360g | 9.61lbs

  • WARRANTY: 3yrs
  • If you have any questions about this frame or bike, please contact our Transition Team:

    Corey Williams
    Toll Free: 866-497-3624 ext. 214
    International | Direct +1 510-529-3054

    Steven Barcikowski
    Toll Free: 866-497-3624 ext. 207
    International | Direct +1 510-529-3052

    * Individual experiences and results may vary.

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