15 kg in size L | € 8,999 | Manufacturer’s website
Transition is a small yet prestigious manufacturer from Bellingham, Washington, and is known for its “no-nonsense” approach. In other words,they build robust, straightforward bikes that are designed uncompromisingly for trail performance. The Transition Sentinel, which is one of the youngest bikes in our test, generates 160/150 mm of travel. Tipping the scales at 15.0 kg, the Sentinel is amongst the heavier candidates in our trail bike comparison test, and with a price of € 8,999, it sits slightly above the average price of the analogue bikes we reviewed. It rolls out of the factory on 29” wheels but can be converted to a mullet bike using a flip chip.
For an overview of the test field head to our “Best trail bike of 2025” comparison test – 16 of the most exciting trail bikes in our 2025 group test
The Transition Sentinel X0 AXS in detail
In purely visual terms, the Transition Sentinel blends seamlessly into the manufacturer’s portfolio, with changes from the previous model becoming apparent only upon closer inspection. Compared to its predecessor, the latest iteration of Transition’s trail bruiser boasts a more rectilinear frame silhouette and slimmer bottom bracket area, and also has a brand-new storage compartment, which the manufacturer calls the BOOM Box. The latter relies on a sturdy closure system, but this sits right under the bottle cage, which makes it slightly impractical to use. With a mounted bottle, the space is limited, making it harder to access. Additionally, the Sentinel has a tool mount on the underside of the top tube for all your trail essentials.
Transition also made some technical improvements: the cable routing is now fully integrated, with cable clamps ensuring a quiet ride on the trail. The chainstay protector has been upgraded too, and is now significantly chunkier, effectively preventing chain slap – only with heavy impacts does the chain still rattle slightly. A narrow TPU protector shields the downtube but doesn’t cover the sides entirely. However, a small rear fender keeps the main bearings clean.
The spec of the Transition Sentinel X0 AXS
The spec of the Transition Sentinel X0 AXS clearly indicates that this bike is designed for demanding trails. FOX supply the 160 mm 36 Factory fork with the new GRIP-X2 damper, which performs slightly better than its predecessor, the already sublime GRIP-2 model. The fork offers countless adjustment options, allowing you to fine-tune the low- and high-speed compressions and rebound setting. At the rear, a matching FOX FLOAT X Factory shock controls 150 mm of travel.
The new FOX Transfer dropper post has a massive 240 mm of travel, which makes it the longest-travel dropper in this test. With the latest iteration of the Transfer dropper, FOX addressed many of the issues of its predecessor, improving its reliability significantly. Braking is taken care of by SRAM MAVEN Silver stoppers, which are paired with a 200 mm rotor at the front and a 180 mm disc at the rear, providing powerful deceleration and good modulation. For most riders, the smaller rear rotor is more than sufficient.
An electronic, 12-speed SRAM X0 Eagle AXS Transmission drivetrain ensures smooth gear shifts, even under load, and relies on a robust direct-mount rear derailleur. DT Swiss supply the robust wheelset consisting of XM 481 aluminum rims and DT Swiss 350 hubs. These wheels are identical to the DT Swiss XM1700 wheelset but built by Transition instead of DT Swiss.
The rims are paired with a 2.5” MAXXIS ASSEGAI tire at the front and a 2.4” MAXXIS Minion DHR II at the rear, both in the EXO+ casing and harder MaxxTerra rubber compound. For more control, we recommend upgrading to a tire with the softer MaxxGrip compound, at least at the front. Riders who push hard and frequently tackle rough trails could upgrade to a DoubleDown casing at the rear for additional puncture protection.
Transition Sentinel X0 AXS
€ 8,999
Specifications
Fork FOX 36 Factory GRIP X2 160 mm
Rear Shock FOX FLOAT X Factory 150 mm
Seatpost FOX Transfer Factory 2025 240 mm
Brakes SRAM MAVEN Silver 200/180 mm
Drivetrain SRAM X0 Eagle AXS Transmission 1x12
Stem ANVL Swage 40 mm
Handlebar OneUp Carbon Handlebar 800 mm
Wheelset DT Swiss XM 481 29"
Tires MAXXIS ASSEGAI MaxxTerra EXO+/MAXXIS Minion DHR ll MaxxTerra EXO+ 2.5"/2.4"
Technical Data
Size XS S M L XL XXL
Weight 15 kg
Specific Features
Storage compartment
Tool Mount
Flip Chip
Mullet compatible
Tuning Tip:
– Front tire with softer MaxxGrip rubber compound
The geometry of the Transition Sentinel X0 AXS
The geometry of the Transition Sentinel X0 AXS impresses with a short 430 mm seat tube, which, combined with the long dropper post, ensures excellent freedom of movement. The reach grows in finely-spaced increments, and measures 480 mm in size L. Thanks to the flip chip, the Sentinel can be converted to a mullet bike, though it’s always delivered as a 29er as standard. In our test, we rode exclusively with 29-inch wheels.
The Sentinel comes alive on rougher trails – a bike that excels at speed and offers plenty of reserves.
| Size | XS | SM | MD | LG | XL | XXL |
|---|---|---|---|---|---|---|
| Seat Tube | 360 mm | 360 mm | 390 mm | 430 mm | 460 mm | 490 mm |
| Top Tube | 527 mm | 549 mm | 577 mm | 605 mm | 632 mm | 660 mm |
| Head Tube | 100 mm | 100 mm | 110 mm | 120 mm | 130 mm | 140 mm |
| Head Angle | 64° | 64° | 64° | 64° | 64° | 64° |
| Seat Angle | 79.8° | 79.3° | 78.7° | 78.3° | 77.9° | 77.6° |
| Chainstay | 436 mm | 436 mm | 440 mm | 442 mm | 446 mm | 448 mm |
| BB Drop | 15 mm | 25 mm | 25 mm | 25 mm | 25 mm | 25 mm |
| Wheelbase | 1173 mm | 1208 mm | 1237 mm | 1267 mm | 1302 mm | 1332 mm |
| Reach | 415 mm | 430 mm | 455 mm | 480 mm | 505 mm | 530 mm |
| Stack | 592 mm | 615 mm | 621 mm | 633 mm | 642 mm | 651 mm |
The Transition Sentinel X0 AXS on the trail
Uphill, the Transition Sentinel places you in an upright yet comfortable pedalling position. On flat terrain, there’s only a slight pressure on your hands, which makes the Sentinel perfectly suitable for long days in the saddle. Despite this, the front end always remains planted on the ground, even in steep climbing sections. The rear suspension bobs only slightly, so reaching for the climb switch is only necessary on very long climbs. However, the Transition can’t quite match the excellent climbing performance of the uphill champions in this test, the Pivot Switchblade and Ibis Ripmo.
Downhill, the Sentinel excels on fast, open trails. In high-speed sections littered with rock gardens and nasty root carpets, the Sentinel is impressively composed, allowing you to follow your line with great precision. Also, it rewards riders who actively weight the front wheel and choose their lines carefully: the Sentinel holds its line securely and absorbs big hits with ease, without ever truly reaching its limits. In this terrain, it outperforms almost every bike in this comparison test, with only the Atherton S.150 pushing ahead even further.
On flowing bike park trails and jumps, the highly capable suspension delivers plenty of pop, turning the Sentinel into a rocket for airtime enthusiasts. It handles bigger landings without breaking a sweat, which is partly due to the generous reserves. However, the firm suspension comes at the expense of traction, making the bike feel a slightly cumbersome in tight, consecutive corners and hairpin switchbacks, thus requiring active body movements to hold the line. Riders lacking sufficient speed may find the Sentinel a bit sluggish in such scenarios.
The Transition Sentinel X0 AXS combines a sleek design with exceptional downhill performance – a true stylish trail monster.
On narrow, rooty trails in steep terrain, it becomes clear that the Sentinel is built for experienced riders who can bring the necessary dynamism to the bike. Those who reach the minimum speed and push the Sentinel will be rewarded with a riding experience that combines control and reserves, even when on extremely technical trails.
The Transition Sentinel X0 AXS proves to be a bike that plays to its strengths on fast, challenging trails and rough terrain. An experienced rider who actively engages with the bike will be rewarded with a flow that elevates their adrenaline high even further.
Who should take a closer look at the Transition Sentinel X0 AXS?
The Transition Sentinel X0 AXS is an outstanding all-rounder for riders who regularly push their trail bike to the limit. It’s designed primarily for downhill-oriented trail riders seeking a versatile companion that excels on challenging trails but can also handle a day at the bike park. At the same time, the efficient uphill performance makes it suitable for longer days in the saddle, offering plenty of comfort and stability. The bike provides a lot of feedback from the ground, and rewards an active riding style, though it requires a rider capable of managing that feedback.
Our conclusions about the Transition Sentinel X0 AXS
The Transition Sentinel X0 AXS combines a clean, rectilinear design language with thoughtful details and the practical BOOM Box storage compartment. It impresses with high stability and ample reserves, allowing it to outpace most competitors in rough terrain. However, it falls short of the most agile bikes in this test. Despite this, the Transition Sentinel is a versatile all-round bike, well-suited for long tours thanks to its comfortable riding position, while also handling rowdy bike park sessions with ease.
Tops
- Very composed
- Highly capable suspension
- Well-thought-out updates
Flops
- Lacks top-tier agility
- Requires an experienced rider
For more info, head to Transition’s website.
The test field
For an overview of the test field head to our “Best trail bike of 2025” comparison test – 16 of the most exciting trail bikes in our 2025 group test
All bikes in test: Atherton S.150 | Canyon Spectral CF LTD | Canyon Spectral:ONfly CF LTD | Ibis Ripmo XT | MERIDA eONE-SIXTY SL | Norco Optic C1 | Orbea Rise LT M-LTD | Pivot Switchblade Team X0 Transmission | RAAW Jibb V2 | Rocky Mountain Instinct C70 | Santa Cruz Bronson CC X0 AXS RSV | Santa Cruz Hightower CC X0 AXS RSV | Specialized S-Works Stumpjumper 15 | Transition Sentinel X0 AXS | Trek Top Fuel 9.8 GX AXS | YT JEFFSY CORE 5 CF
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Words: Simon Kohler Photos: Peter Walker
