Brandon Hainsley

22nd February 2025

First Ride Review: 2025 Transition Bikes Sentinel – A Veteran MTB Rider’s Take

I’ve ridden a lot of bikes over the years, from twitchy XC whips to full-on downhill beasts, and when it comes to all-mountain machines, the 2025 Transition Sentinel is a bike that immediately caught my attention. With 150mm of rear travel, a 160mm fork, and Transition’s GiddyUp suspension, this rig is built to handle just about anything you throw at it. But does it live up to the hype? Let’s break it down.

First Impressions – Built for Big Terrain

Right out of the box, the Sentinel’s frame looks clean, aggressive, and modern. The full-carbon version comes with Transition’s new “Boom Box” internal storage, which is a game-changer for carrying spares and snacks on long rides. The aluminum frame skips the storage, but it’s still a solid build.

A few things stood out to me immediately:
✔️ 29-inch wheels (MX option available for mullet fans)
✔️ Size-specific chainstays for more balanced handling
✔️ Frame-compatible with up to a 65mm stroke shock, bumping rear travel up by 10mm if needed
✔️ Clean internal cable routing

Let’s get into the ride experience because that’s what really matters.

Climbing – A Solid Grinder, Not a Rocket

Let’s be real—this isn’t a featherweight XC machine, but for a long-travel 29er, the Sentinel climbs respectably well.

“On climbs, the Sentinel offers a comfortable pedaling position suitable for long days in the saddle. While the rear suspension remains neutral on smooth ascents, it may exhibit some bobbing on technical climbs, making the use of the climb switch beneficial to conserve energy. Overall, the Sentinel is a competent climber but prioritizes descending prowess.” Enduro MTB

Climbing Highlights

Steep Seat Tube Angle (77.5°) – Puts you in a strong position for technical climbs.
GiddyUp Suspension – Keeps the rear end planted, minimizing energy loss.
Stiff Frame – Helps transfer power efficiently when grinding up fire roads.

Climbing Challenges

Some Suspension Bob – On smoother climbs, I noticed a bit of movement in the rear. A quick flick of the climb switch helped.
Weight – It’s not the lightest climber, and you’ll feel that on long grinds.

Bottom line? The Sentinel gets the job done on the way up, but its real strength is what happens when gravity kicks in.

Descending – A Freight Train with Style

Now we’re talking. If you love long, rough, high-speed descents, the Sentinel absolutely rips.

“Descending is where the Sentinel truly excels. The bike offers stability and control on technical descents, with its geometry and frame stiffness providing confidence on aggressive terrain. Riders have praised its ability to handle high-speed sections with precision, while still being nimble enough for playful maneuvers. The suspension design ensures the bike remains composed, offering a balance between plushness and support.” bebikes.com

Descending Strengths

Slack Head Angle (64°) – This thing eats steep, techy terrain for breakfast.
Balanced Suspension – Keeps the bike high in its travel, making it predictable and controlled.
Big-Wheel Confidence – The 29ers roll over everything. Roots? Rocks? Drops? No problem.
Cornering Stability – The revised chainstay lengths give each frame size a balanced, controlled feel.

Descending Drawbacks

Not as Playful as Some Bikes – The long wheelbase and big wheels make it stable, but it’s not as flickable as a shorter-travel bike.
Manuals & Jumps Need Some Effort – You’ll need a strong pull to get the front end up.

If your riding style is fast and aggressive, you’ll love the Sentinel. If you prefer poppy, jibby trails, you might want something a bit more playful.

Frame and Design

The 2025 Sentinel features a full carbon frame equipped with Transition’s new “Boom Box” internal storage system, providing riders with convenient on-the-go storage solutions. The frame is designed to accommodate both 29-inch wheels and a mixed-wheel (MX) setup, offering flexibility based on rider preference. Size-specific chainstay lengths ensure balanced handling across all frame sizes, ranging from XS to XXL. Additionally, the frame is compatible with up to a 65mm stroke shock, allowing riders to increase rear travel by 10mm if desired. Pinkbike

Suspension and Geometry

Maintaining 150mm of rear travel paired with a 160mm fork, the Sentinel continues to utilize Transition’s GiddyUp suspension design. The updated kinematics aim to provide a balance between climbing efficiency and descending capability. A 64-degree head tube angle combined with a steep seat tube angle places riders in an optimal position for both ascents and technical descents. The suspension is noted for keeping the bike higher in its travel, offering control and responsiveness over rough terrain.

How Does It Handle?

The Sentinel finds a sweet spot between agility and stability. It’s not a race bike, but it’s not sluggish either. It’s built for real-world enduro and aggressive trail riding.

✔️ Fast & Flowing Trails: Feels planted and stable but still quick.
✔️ Techy Rock Gardens: Carries momentum effortlessly, stays composed.
✔️ Drops & Jumps: Loves bigger hits but takes a bit more effort for tight poppy lines.

Overall, the Sentinel is confidence-inspiring on the descents and stable at high speeds.

Sentinel 2025 Technical Specs

Here’s a detailed breakdown of the 2025 Transition Sentinel specs:

Feature	Specs
Frame Material	Carbon / Aluminum
Wheel Size	29” (MX compatible)
Rear Travel	150mm
Fork Travel	160mm
Head Tube Angle	64°
Seat Tube Angle	77.5°
Chainstay Length	Size-specific
Frame Storage	Yes (Carbon only)
Suspension Design	GiddyUp
Weight	~31-34 lbs (varies by build)

Final Verdict – Is the Sentinel Right for You?

If you’re an aggressive trail rider who loves high-speed descents, technical terrain, and all-day adventures, the 2025 Transition Sentinel is an absolute beast.

Who It’s For:

✔️ Riders who prioritize stability & confidence on descents
✔️ Those who tackle rough, high-speed trails regularly
✔️ Anyone who wants a durable, long-lasting trail weapon

Who Might Look Elsewhere:

❌ If you want a super playful, flickable bike
❌ If weight and ultra-efficient climbing are your main priorities

💭 Final Thoughts

After putting the 2025 Transition Sentinel through its paces, I can say this: it’s a bike that rewards speed and confidence. If you send it big, ride hard, and love technical trails, this bike won’t let you down.

For those looking for a fast, stable, and aggressive enduro-ready machine, the Sentinel is one of the best all-mountain bikes of the year.

The 2025 Transition Bikes Sentinel continues to uphold its reputation as a capable and versatile all-mountain bike. With thoughtful updates to its frame design, suspension kinematics, and geometry, it caters to riders seeking a bike that excels in descending while maintaining respectable climbing performance. Whether tackling technical trails or enjoying flowy singletrack, the Sentinel is designed to inspire confidence and deliver a dynamic riding experience.