Tout Terrain Ceres GT Select 5.1: The Gravel Bike That (Almost) Does It All

Note: Tout Terrain provided me with the bike for testing upon my request.

Do you know that feeling when you get on a new bike, ride the first few meters, and think you’ve never gone so fast, so effortlessly, so well before?

I test a lot of bikes, so I often get to experience this amazing feeling. And with the bike I’m introducing today, that feeling lingers: the Tout Terrain Ceres GT Select 5.1.

If I were to build a gravel bike today, my requirements would look like this:

• A lightweight steel frame with sporty geometry for performance riding, yet suitable for bikepacking.
• A direct mount option to use SRAM Transmission or XPLR drivetrains (and future Shimano ones). Of course, with UDH for classic derailleur setups.
• Generous tire clearance – as gravel riding becomes more mainstream, riders increasingly want tires wider than 45mm.
• Ideally even Boost standard, although that leans more toward MTB territory.
• Suspension fork compatibility for more demanding terrain and added comfort.
• A high system weight limit to handle gear and heavier riders.
• Plenty of mounting points for bags and accessories.
• Customization options beyond “off-the-shelf” specs.

The Tout Terrain Ceres GT meets many of these demands – a bike I already named one of my “7 for 2025” favorites for bikepacking and touring.

Back then, I wrote:

“When I first looked at the Ceres from Tout Terrain, I was impressed. Clearly, they paid close attention to market trends and the needs of performance-minded gravel riders: a slim and lightweight steel frame, direct mount compatibility, more tire clearance, and ready for a suspension fork.”

Let’s break it down:

Lightweight Steel Frame with Sporty Geometry

With the Ceres GT, Tout Terrain has built a gravel bike whose geometry strikes a balance between sporty and touring-friendly. It offers a comfortable position for long distances while remaining agile and precise for technical trails and fast sections. Depending on tires and load, the bike can be either performance-oriented or more relaxed for long-haul touring.

With a reach of 389 mm, stack of 578 mm (frame size M), and a 71° head angle, the Ceres GT’s geometry sits in the sweet spot between race-oriented gravel bikes and comfort tourers.

Its moderate reach and stack allow for a comfortable yet athletic riding position. The combination of a slack head angle and longer chainstays ensures stability on rough terrain.

With a stack-to-reach ratio of 1.49, the Ceres GT sits at the upper end of the sporty category – comfortable enough for long rides, agile enough for gravel.

The stack-to-reach ratio is a measure of the relationship between the upright sitting position (stack) and the sporty extension (reach). It gives a quick impression of how comfort-orientated or sporty a bike frame is designed:

This is evident in real-world riding – the Ceres is fast but also comfortable even on long rides with luggage. It retains that fun, sporty feeling described at the start.

A major factor is the steel frame, made from heat-treated 4130 Chromoly steel, branded “Thermocrom” by Tout Terrain – a proprietary tube set used in their high-end frames. It offers low weight, high strength, and the classic ride feel of steel. The heat treatment allows for thinner walls, improving both durability and comfort.

This special Thermocrom tubeset is also used in the Tout Terrain Blueridge GT and Tanami Xplore models.

Direct Mount Option

With the rise of electronic and now mechanical direct-mount drivetrains from SRAM in mountain biking, these are becoming more common on modern gravel bikes. Direct mount means the derailleur is mounted directly to the frame instead of a derailleur hanger.

SRAM Transmission AXS or XPLR allows mixing road and MTB components—for example, using a gravel chainring up front and an MTB cassette at the rear for broader gearing.

On my Salsa, for instance, I run a SRAM Rival AXS in front with a SRAM GX AXS Transmission derailleur and a 10-52 cassette. It lets me hammer on flats and still climb with gear in rough terrain.

Tout Terrain took this idea to heart. The production Ceres GT comes with a SRAM Apex AXS in front (40T chainring) and a SRAM GX AXS Transmission with a 10-52 cassette at the rear—great even on 15% climbs, without pushing the limits.

If you’re not into electronic shifting, the frame accepts a derailleur hanger via UDH, allowing traditional drivetrains. However, the frame is built exclusively for 1x drivetrains—no front derailleur mounts. A wise move, as 1x setups are proven and ideal for gravel.

Speaking of chainrings, the Ceres GT uses a T47 bottom bracket, combining easy maintenance with high stiffness—ideal for demanding tours. The type of T47 BB depends on your crank spindle diameter (24–30 mm) and installs with standard tools (like BSA), not specialized ones like Hope.

Another modern touch: the Ceres GT Select frame features internal cable routing. For electronic builds, brake lines run internally through the fork and frame—a cleaner look and helpful when mounting bags. The downside is more hassle during service or fork swaps, but it’s manageable.

Tire Clearance

The Ceres frame clears up to 2.1″ tires (both 650B and 700c), possibly even 2.25″ depending on rim/tire combos—making it adaptable to nearly all terrain.

The test bike comes with Tout Terrain’s full carbon Gravel Fork SL, weighing around 540g. It has internal routing for a dynamo hub and three mounts per side for anything cages. The fork has a 45mm offset and clears up to 2.1″ tires.

For more comfort, you can opt for the Cane Creek Invert suspension fork with 40mm travel. It performed well at the Bohemian Border Bash. Tire clearance here is limited to 50mm, though.

Wheelset-wise, the Ceres GT uses DT Swiss G540 rims with Tout Terrain hubs.

The G540 is solid but a bit heavy. It’s 24mm internal, ~28mm external, 25mm high, and 535g (32h). While not the widest rim, the stock 44mm tires fit well—and up to 2.1″ should too. They’re stable, tubeless-ready, and good value. If you want to upgrade, start with the wheels.

The hubs—Tout Terrain EX-F2 (front, Centerlock) and EX-R2 (rear, 10–12 speed, Centerlock)—have a soft whirr similar to Onyx hubs and are tuned for gravel/adventure. Built and hand-laced in-house at Tout Terrain’s facility in Gundelfingen, Germany.

The included tires are 44mm Vredestein Aventura. I hadn’t used them before, and while generally fine, they felt slippery on gravel. According to BicycleRollingResistance, they have higher rolling resistance (about 25W at 2.6 bar) compared to ~17W for competitors.

The Ceres GT uses a 12×142 mm thru-axle rear and 12×100 mm front—standard for gravel, but not Boost. I like Boost for wider tires, stronger wheels, and better 1x chainlines, but I understand compromises must be made. Still, bikes like the Salsa Cutthroat or Bombtrack Hook ADV offer Boost.

High System Weight Limit

According to the Robert Koch Institute, the average body weight of men and women in Germany is 86kg and 71kg respectively. This is very high, but there are other reasons for this and cycling can certainly be a solution.

What I’m getting at, however, is that many gravel bikes have a very low system weight. This refers to the permissible total weight, consisting of the bike, rider and payload.

The system weight of modern gravel bikes is often 110-120kg – depending on the frame material and construction. I weigh 84kg + 11kg bike = 95kg. This theoretically leaves me with a payload of only 15 to 25kg. That’s no problem for a light bikepacking trip, but if you want to go on a longer trip, you quickly reach your limits.

Therefore, a higher system weight is already very good and with 130kg the Ceres GT offers enough capacity even for heavier riders.

Speaking of weight: according to the manufacturer, the Ceres GT weighs 10.5kg. I weighed 11kg. But it is quite light and if you like, you can get to a weight under 10kg by choosing other components.

Plenty of Mounting Points

The Ceres GT has ample mounts for bottles, bags, and gear—ideal for bikepacking. The main triangle offers enough space for a custom bolt-on frame bag, which would look very sleek.

I like the top tube mounts for a stable, slip-free bag. There are also mounts under the top tube and down tube, plus mounts for racks and fenders.

Loaded bikes often experience handlebar flop when stationary—Tout Terrain addresses this with a steering stop built into the spacer below the stem. Simple, but clever.

Customization Options

Tout Terrain offers the Ceres GT as a fixed-spec GT Select 5.1 version. That’s the model I tested.

As mentioned, it comes with SRAM Apex AXS/GX AXS Transmission, a 40T chainring, 10–52 cassette, DT Swiss G540 wheels, Tout Terrain hubs, and Vredestein Aventura tires.

Brakes are SRAM Apex: 180mm front, 160mm rear. Adequate for most use, but under sustained braking the bite point fades.

Handlebar is Tout Terrain’s 440mm wide gravel bar with 16° flare. I’d prefer wider, but it worked well. A 100mm stem is standard on the Select and matches the bike’s handling well. I rode a size L frame, which fit my 184 cm height and 80 cm inseam.

Price: €3,700, available from mid-August 2025.

Tout Terrain also offers customization. You can choose frame colors using sliders on their website (a RAL code would be a nice addition). Personally, I love the rainbow option.

Beyond that, drivetrain type is fixed (AXS 1x), but if you want to build the Ceres GT differently: a frameset option will be configurable from June / shortly.

You can choose between the carbon or Cane Creek fork. The handlebar can also be changed to the Longhorn Comfort bar (21° flare), which resembles the Salsa Woodchipper. Sadly, it’s only available with the bike, not separately.

The stem can be chosen in 70 or 100 mm—go for 100 mm unless you want radically different handling.

Want a premium touch? Upgrade the headset to one from Chris King.

When it comes to choosing a luggage carrier, I recommend taking a look at the Graveloption. Here the Racktime Viewit front carrier is offered. This would be an interesting option for anyone who wants to easily transport some luggage at the front and doesn’t always want to mount a bag or harness. The carrier is mounted on the steerer tube, weighs only 190g and can carry up to 5kg.

Wheels and tires unfortunately can’t be customized—I’d love that option to build a more premium version. You can customize saddle and seatpost, though.

Fully specced, I ended up around €5,600. High, but fair given the quality, German manufacturing, and thoughtful design.

Final Verdict: Tout Terrain Ceres GT

Looking back, the Ceres GT is a gravel bike that genuinely comes close to the marketing promise of being the “do-it-all” solution. A bike for all occasions.

The Ceres GT Select 5.1 is a well-designed, modern gravel bike that impresses with geometry, build, tire clearance, and mounting options. It can be a fast gravel racer or a long-distance hauler.

If you’re looking for a bikepacking-friendly, stylish, and capable gravel bike—this one’s a great pick. It looks great, too.

I stick to my initial enthusiasm: this bike is fun every time, and always feels new. Fast on tarmac and trails, stable even with gear. It was a bit twitchy in sand/mud—due to the tires.

I rode the Ceres GT for 350 km. With stock tires, it’s limited off-road—but tires make a huge difference. Technically, the Ceres GT is top-tier.

I would like Tout Terrain to offer other shifting options in the configurator, such as the XPLR or classic shifting with UDH derailleur hanger. In other words, exactly what the Ceres GT stands for: gravel performance or bikepacking. And both options naturally have different requirements in terms of gearing or tyres, which can then ideally be configured. But as far as I could hear, this is already being planned and should be available soon.

It’s likely not profitable to offer such wide variety upfront—but selling the frameset separately would be a great start for custom builds.

Either way, anyone seeking a sporty steel gravel bike with modern drivetrain, bikepacking capabilities, and made in Germany should seriously check out the Tout Terrain Ceres GT.

You’ll have a lot of fun!

And if you’re wondering where the name Ceres originally comes from: it’s derived from the Ceres 500 Bikepacking Race in South Africa, which leads 520 kilometres through the landscape of the Cederberg region.