New GRIN ONE Enduro Bike on Test – Grinning All Day?

Robust, versatile, and refreshingly clean – the GRIN ONE aims to bring it all together. Whether enduro tracks, alpine tours, or flow trails: according to the manufacturer, this alloy bike from the BIKELÄND Eberbach area is built for tough enduro trails, technical alpine terrain, and long climbs. We put it to the test to find out if it delivers on that promise.

New brand, big promise: with the GRIN ONE, the young brand from Eberbach Germany launches straight into the enduro world right on the BIKELÄND trails. Their first bike is already a statement – or more precisely, a versatile alloy frame kit with a Horst link rear suspension, designed in Germany and manufactured in Taiwan. With just one frame, GRIN aim to cover three different travel categories. The goal? To take on everything with the GRIN – from demanding enduro tracks and alpine adventure routes to playful flow trails. Three bike categories, size-specific travel, and a clean look are meant to make for a coherent concept. But at € 2,450 for the frame kit without a shock, the ONE already plays in the upper alloy league, comparable to the RAAW Madonna V3 – so it’s not exactly a budget-friendly entry point.

Depending on the frame size, the GRIN ONE can be built up either as a mullet setup or as a full 29er. We rode the bike in a mullet configuration – 29” up front, 27.5” at the rear. Adding up the parts on our custom GRIN brings the total to € 6,942. How this setup performs on the trail – that’s what we’ll dive into here.

Just Naked – The GRIN ONE Enduro Bike in Detail

The brushed aluminum is the first thing that catches your eye when the GRIN ONE rolls into view. The 6066-T6 aluminum tubes appear almost delicate next to the oversized welds, creating a slim silhouette that still conveys strength and robustness. In addition to the raw, matte finish of the Just Naked version, the bike is also available in the matte-black “Sneaky Stealth” paint job and glossy dark-green “GRIN Your Face”. All three versions feature the distinctive GRIN logo on the downtube, while the back of the seat tube subtly points to the German brand’s very first bike, the “ONE.”

The cable routing on the GRIN ONE Enduro looks a bit untidy in the cockpit area but the lines disappear neatly into the headset, where they’re clamped securely into the downtube. Inside the frame, they aren’t guided through channels but are wrapped in foam sleeves to prevent rattling. Since the bike – or rather the frame – is only sold as a frame kit, GRIN equipped our build with CAPGO OL Noise Protection foam sleeves in 9 mm and 11 mm. The lines re-emerge at the rear end and are fixed under the chainstay with zip ties. Small spoiler from our test: on the trail, the cables stayed completely silent.

The GRIN ONE doesn’t feature an integrated storage compartment – but this is normal for alloy frames, since such a solution requires significant effort in development and production. At least there are mounting points: a tool mount can be attached under the top tube, and the downtube includes additional bosses for a bottle cage.

When it comes to serviceability, the GRIN ONE scores with exemplary transparency: on the manufacturer’s website and in the user manual you’ll find a detailed exploded view – from the washer to the cable clamp bolt. There are also helpful tips on how to assemble and maintain the bike.

The Specs of Our GRIN ONE Enduro Bike

For our test, the GRIN Bikes engineering team didn’t do things halfway: the pioneers from the bike town on the Neckar built us a fully assembled ONE and pulled out all the stops when it came to the spec.

When it comes to braking, GRIN went all-in on power: the Trickstuff DIRETTISSIMA are considered the ultimate boutique four-piston brakes. With a consistent bite point even on long descents, they’re paired with 203 mm Trickstuff Dächle rotors (front and rear), ensuring excellent modulation – almost as precise as a bartender mixing a cocktail.
The levers are mounted on 800 mm PRO Tharsis aluminum handlebars with 35.0 mm clamp diameter, 9° of backsweep and 20 mm of rise. The bars are paired with a short 35 mm alloy stem.

For the suspension, GRIN rely on a powerful duo from RockShox’s top tier suspension models: a ZEB Ultimate with the Charger 3.1 damper generates 170 mm of travel at the front, while a Vivid Ultimate shock controls 166 mm of travel at the rear. Together, they provide a highly tunable setup with low- and high-speed compression plus low-speed rebound adjustment.

For the drivetrain, GRIN rely on a mechanical SRAM GX Eagle mounted on a UDH mech hanger – meaning the frame is also ready for a SRAM Transmission groupset. The GX is a solid mid-range derailleur that delivers reliable performance and, in this case, is paired with a 12-speed cassette and a matching 30-tooth chainring.

Robust frame seeks robust wheels – that could be the GRIN ONE’s Tinder bio. It finds its match in the DT Swiss EX 1700 alloy wheelset, which we’ve consistently had good experiences with in the past.
They’re paired with a strong tire combo from MAXXIS: up front, a 29” x 2.5” ASSEGAI with EXO+ casing and soft MaxxGrip compound; at the rear, a 27.5” x 2.4” Minion DHR II with DoubleDown casing and the slightly harder MaxxTerra compound. This setup strikes a solid balance between grip and puncture protection. For heavier riders, however, we’d recommend opting for the more robust DoubleDown version on the front once the ASSEGAI needs replacing. And if you’re keen on trying out different tires or want an overview of what’s out there, check out our big tire group test.

For the dropper post, GRIN equipped our bike with a OneUp V3 offering 210 mm of travel and a 31.6 mm diameter – the very model that took the win in our big dropper post group test. It can be fully inserted into the frame, giving plenty of freedom of movement on the trail.
The frame itself is designed to be compatible with most common components. However, the manufacturer notes that some parts with especially large dimensions might not fit. If in doubt, it’s best to check directly with GRIN.

The Geometry of the GRIN ONE – One Frame = Three Bikes

One frame, three bikes – that’s how simple the GRIN ONE concept sounds on paper. The same frame can be built up into three categories depending on the shock: as an enduro with 170/166 mm (f/r), as an alpine bike with 160/161 mm (f/r), or as a trail bike with 150/149 mm (f/r). This is made possible by different shock strokes: 65 mm for enduro, 62.5 mm for alpine, and 57.5 mm for trail. GRIN has tested both air and coil shocks in the frame, with the exact approvals listed in the manual.
How the three variants truly differ can only be judged in a direct back-to-back test on the trail. On paper, the concept sounds simple, but in practice things often play out differently – and not without reason: why else would manufacturers develop dedicated frames for specific travel categories? Still, it’s a practical way for a new brand to bring several bikes to market at once, even if that comes with small downsides like added weight or geometry that isn’t fully optimized for each use case.

Once you’ve chosen a travel option, the next decision is whether to go mullet or full 29er. In frame sizes L and XL, both setups work smoothly with tires up to 2.5”; beyond 2.6” things get tight. In size M, GRIN allows a maximum of a 2.4” MAXXIS Minion DHR II or tires with similar dimensions – then the 29er setup works, too.
However, swapping the rear wheel from 27.5” to 29” does affect the geometry: the seat angle steepens by 0.8°, the head angle by 0.9°, reach increases by 9 mm, and stack drops by 7 mm. Bottom bracket drop increases from –12 to –19 mm.

A flip chip on the lower shock mount lets you choose between a high and low setting. With the smaller 27.5” rear wheel, the head angle shifts from 63.9° (high) to 63.2° (low) – pushing close to downhill territory. The seat angle varies between 77.4° and 76.7°, keeping it firmly in line with modern enduro geometries. Reach shortens by 8 mm, from a moderate 485 mm (high) to 477 mm (low), while stack height increases by 6 mm from 648 mm (high). Bottom bracket drop rises from –2 mm to –12 mm. So, if you swap in a bigger 29” rear wheel, you can use the flip chip to counterbalance the geometry changes.
Depending on the frame size, the chainstays grow accordingly, which is meant to ensure balanced proportions. As the chainstays get longer, travel also increases across the frame sizes.
The GRIN ONE is available in four sizes, from S to XL. Thanks to short seat tubes, sizing remains flexible: even smaller riders can opt for a larger frame without sacrificing dropper insertion depth. In size L, the insertion depth is 343 mm, allowing for long droppers. Even the small size S frame, with 303 mm insertion depth, can accommodate long posts that can be fully slammed.

Size	S	M	L	XL
Seat Tube	390 mm	410 mm	430 mm	450 mm
Top Tube	562 mm	590 mm	618 mm	647 mm
Head Tube	109 mm	118 mm	126 mm	133 mm
Head Angle	63.2°	64.1°	64.1°	64.1°
Seat Angle	76.7°	77.5°	77.5°	77.5°
Chainstay	435 mm	440 mm	445 mm	450 mm
BB Drop	12 mm	19 mm	19 mm	19 mm
Wheelbase	1,216 mm	1,251 mm	1,286 mm	1,321 mm
Reach	425 mm	460 mm	486 mm	514 mm
Stack	638 mm	639 mm	647 mm	653 mm

The GRIN ONE on the Trail

Stuttgart home trails? Check! Bikepark La Bresse and Oberammergau? Check! We pushed the GRIN up and down trails across a wide range of terrain and conditions – and even used it for commuting to the office. Overall, we spent most of the time riding it in the high setting.

When you sit on the GRIN ONE, you’re well balanced between front and rear. This makes it easy to spend a full day in the saddle without your limbs going numb. On forest road climbs, the rear end bobs slightly while pedaling. For long ascents, it’s worth reaching for the climb switch for more efficiency – for short loops, not so much. The bob is barely noticeable, and reaching down is too much hassle ;). On technical uphills, the rear end still generates plenty of traction, while the front wheel stays planted even on steep pitches without lifting – nice!

When gravity takes over, the GRIN ONE places you on top of the bike rather than integrating you between its wheels. Combined with the low front end and the bar’s minimal rise (on our test build), initially this gave us the sensation of going over the bars. Once we added a spacer under the stem, though, that sensation disappeared. In the high setting, the ONE pumps rollers well and eagerly builds speed. The suspension irons out rock gardens and root sections with authority while keeping things pleasantly composed, giving the bike a secure feel even in steep, rough terrain. In the low setting, however, the GRIN ONE showed some wheel flop on our flatter home trails. What delivers a planted, confidence-inspiring ride on steep, technical sections can feel a bit wobbly on more moderate terrain.

Just cruising along? That’s not the GRIN ONE’s strong suit – it wants to be ridden actively. With the right input, it rewards you with plenty of speed, letting you leave your fingers off the Trickstuff DIRETTISSIMA brakes for a little bit longer. That’s how the GRIN puts a smile on your face. Botched landings? No problem – the suspension matches the bike’s character perfectly and provides plenty of support.

Barely out of one corner, you’re already diving into the next – and the GRIN ONE handles that with confidence, translating steering input directly and precisely. Paired with the smaller rear wheel, the GRIN behaves like an agile gazelle, darting playfully and carrying more speed from turn to turn.

Who Should Take a Closer Look at the GRIN ONE?

For riders looking for a versatile bike that they can build up to their own preferences, the GRIN ONE is spot on. Since it’s only available as a frame set, customization is in the rider’s hands anyway. In the enduro build we tested, it impressed as a lightweight yet robust bike that climbs efficiently enough and really comes alive on the descents when ridden actively. Beginners might feel overwhelmed by the frame’s potential at first, but with some fine-tuning and the right flip chip setting, the bike works well for them too.

Conclusions about the GRIN ONE

With the GRIN ONE enduro bike, the German brand delivered a strong first frame. If you like the alloy look with chunky welds, you’ll get a robust and high-performance enduro bike. In our spec, it proved a capable enduro bike with plenty of reserves, both up and downhill. At 15.3 kg, it’s surprisingly light for an alloy bike with 170/166 mm of travel, which translates into agility and lively handling on the trail. For anyone looking for a versatile bike that can be built to their own preferences, the GRIN ONE is a solid choice.

More information at grin-bikes.de

---

Did you enjoy this article? If so, we would be stoked if you decide to support us with a monthly contribution. By becoming a supporter of ENDURO, you will help secure a sustainable future for high-quality mountain bike journalism. Click here to learn more.

Words: Robin Ulbrich Photos: Peter Walker