Is the BMC Kaius 01 the fastest gravel bike on the market? We have tested it

The BMC Kaius 01 brings together very solid arguments to aspire to be one of the fastest gravel bikes on the market. Extreme lightness, aerodynamic integration, and a tire clearance of up to 52 mm in a bike designed with a very clear goal: to win.

Competition gravel is evolving towards increasingly specific bikes. Faster, more aerodynamic, and lighter. The BMC Kaius 01 is one of the best examples of this trend. We have been able to test it thoroughly, and these are our impressions.

Kaius 01: aerodynamics, stiffness, and integration taken to the maximum

The BMC Kaius 01 has been developed with the premise of being as fast as possible, and to achieve this, BMC has focused the development of the frame on three pillars: aerodynamics, stiffness, and weight.

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Aerodynamics is becoming increasingly important in competition gravel, where average speeds continue to rise. Therefore, the frame of the Kaius 01 incorporates numerous solutions inherited from the Teammachine R, the brand's most advanced road model.

The first striking detail is the so-called Halo Fork, a wide crown fork that helps channel airflow while allowing for generous tire clearance. The Kaius 01 accommodates tires up to 52 mm both front and rear.

The seat post adopts a D-shaped profile to improve aerodynamics without sacrificing absorption capacity, a fundamental aspect in a bike of these characteristics. Just below, the seat tube has a very pronounced profile at its top that gradually narrows to make room for the tire.

The head tube has also been carefully worked, with a narrow front section and shaped sides to reduce drag.

Where the design work is most evident is in the down tube. Its profile evolves along the frame, although it always maintains a truncated aerodynamic section with a flattened top face. Additionally, it integrates a specific bottle cage that fits perfectly into its shapes. According to BMC, this solution makes the bike even more aerodynamic with the bottle installed than without it.

In the seat tube, we find another bottle cage adapted to the frame, although it maintains compatibility with conventional models.

Aerodynamic shapes continue in other points of the frame, such as the union of the stays with the top tube. At the same time, the design of all the tubes also seeks to optimize stiffness through slight edges and smoothly flattened profiles.

In the area of the bottom bracket, a T47 threaded standard with internal bearings has been chosen, a solution that improves both stiffness and integration and also provides a very clean aesthetic finish.

Stiffness has been another aspect that BMC has worked on the most. According to the brand, it increases by 3% compared to the previous generation. It may seem like a modest improvement, but when starting from a very high level and also increasing absorption, the result is clearly noticeable on the bike.

Weight remains another of its strong arguments. Despite improvements in aerodynamics and stiffness, the Kaius 01 remains at 7.62 kg, a truly contained figure.

Although it is a bike clearly focused on competition, BMC has not neglected comfort. Its Tuned Compliance Concept system combines frame design, controlled flex of the post, and the use of larger volume tires to improve impact absorption and reduce fatigue on demanding rides.

The frame also offers numerous anchor points for accessories. On the top tube, we find a mount for a bag, another on the underside of the same tube, and the possibility of installing a third bottle cage under the down tube.

An important detail is that the Kaius 01 is only compatible with wireless electronic groups. Through the integrated cockpit, only the brake hoses run through the steering.

The geometry maintains a clear racing character, although it introduces some changes to improve off-road behavior. The head tube remains quite low, at 126 mm in size 54, although it increases slightly compared to the previous generation. The reach is reduced to 396 mm, and the stack grows by 11 mm to 561 mm.

The steering angle relaxes by more than a degree to 70.8°, while the seat tube increases slightly to 73.8°. The chainstays measure 425 mm, and the wheelbase reaches 1,027 mm. With all this, the Kaius 01 retains its competitive DNA but clearly improves its off-road behavior.

BMC Kaius 01 ONE: the most exclusive at the service of speed

We have been able to test the highest model in the Kaius 01 range, and as expected, it does not skimp on any aspect.

The component that stands out the most is the integrated ICS Carbon Aero cockpit. In addition to integrating perfectly into the frame and steering, it features a truly spectacular design. It shares development with the road range and has been designed in collaboration with the Tudor Pro Cycling Team.

It has a marked aerodynamic profile and dimensions that clearly reflect current trends. It is available in three sizes, and our unit, in size 54, had the smallest one. With a 12° flare, it offers 370 mm of width at the top and 420 mm at the bottom. The other two options are 390/440 and 410/460 mm.

For the transmission, the best that SRAM offers for gravel has been used: a complete Red XPLR AXS group, including cranks with a power meter. It has a 13-speed 10-46 cassette combined with a 42-tooth chainring.

The wheels also deserve special mention. The CG39SL uses aerodynamic carbon rims and striking flat carbon spokes with specific hubs for this system.

They are fitted with Continental Terra Competition Race Rapid 45 mm tires, the model that Continental has specifically developed for competition gravel.

The rest of the assembly maintains the same level, with an aerodynamic profile post designed to provide some flex and a Fizik Vento Argo X1 saddle with carbon rails.

A curious detail is that our unit included an integrated dorsal support on the saddle closure, an accessory that is usually provided to be mounted only when necessary.

The BMC Kaius 01 ONE impresses at first glance

In person, the Kaius 01 immediately captures attention. Just stopping to look at the details reveals the enormous work done in the design of the frame and the integration of the bottle cages, which give it a very marked personality.

The gaze quickly turns to the cockpit, with a clearly racing design that would even stand out on a road bike. The wheels also catch the eye. Although they lack large logos, just looking closely reveals that we are dealing with a truly high-end product.

It is also surprising how little tread the tires have, reduced practically to a slight ribbing on the tread.

Even before mounting the pedals, we wanted to check its weight, as from the very first moment it conveys a sense of lightness. The scale confirmed the good impressions: our unit in size 54 weighed 7.62 kg with the bottle cages installed and the GPS mount.

When we started pedaling, the first sensation is that of being on a road bike. The position feels very natural, and in our case, size 54 fit us perfectly with a height of 174 cm.

From the first meters, it conveys great lightness and stiffness that invites you to ride fast. On asphalt, there is hardly any penalty compared to a road bike. The only limit may come from the single chainring transmission, although with the 42-10 gearing, you really have to ride fast to run out of gears.

From the very beginning, it is clear that it can be an excellent option for those looking for a single bike capable of combining road and gravel with very high performance.

The BMC Kaius 01 flies low

On fast tracks, it is one of the gravel bikes with which we have ridden the fastest. The stiffness and efficiency make it really easy to accelerate and maintain high speeds.

This also requires paying attention in the corners, as even riding on flat terrain, we reach them very quickly. If the ground offers little grip, it is necessary to brake in advance and trace with precision to take advantage of tires clearly oriented towards speed.

Irregularities are filtered thanks to the design of the frame, the post, and the 45 mm tires, which in tubeless allow riding below 2 bars of pressure. It is not the most comfortable gravel bike we have tested, but it also does not aim to be. Its orientation is clearly competitive. Additionally, it accommodates tires up to 52 mm, a size that would significantly increase comfort with minimal loss of rolling capacity.

Climbs are another of its strong arguments. On short climbs, it stands out for its reactivity and, on long ascents, the combination of lightness and stiffness conveys the sensation that every watt goes directly to the rear wheel. The 42-46 gearing also allows maintaining a comfortable cadence even on significant slopes.

On descents, the geometry provides enough stability to tackle high speeds with confidence. However, on surfaces with little grip, it is advisable to brake before entering the corners. On asphalt, on the other hand, the Kaius 01 again resembles a road bike, offering enormous safety even when the surface is not perfect.

As for the assembly, it is difficult to find faults. The SRAM Red XPLR offers fast and precise shifts even under load. The brakes represent a clear evolution compared to previous generations and provide outstanding power with one finger.

The wheels have proven to be very responsive and we have not noticed any strange behaviors despite their relatively high profile, even in the wind.

The cockpit has also ended up convincing us off-road. Although the top part is very narrow, just switching to the lower grip provides a good level of control and comfort.

Conclusions

After several weeks riding the Kaius 01 on all types of terrain, the conclusion is clear: we are facing one of the fastest gravel bikes we have tested.

However, it is important to be clear about the use for which it has been designed. If our routes mainly take place on very rough terrain, it is probably not the most suitable option, as the racing posture and a frame clearly oriented towards stiffness do not prioritize comfort.

However, if our outings combine road and fast tracks, or we are looking for a bike to compete at the highest level, the BMC Kaius 01 is a hard option to match.

The new BMC Kaius 01 range comes in three versions. The ONE model, which is the one we tested, is priced at €10,999. The TWO model features SRAM Force, retains the carbon rims, and the integrated cockpit for €7,999. The entry-level model is the THREE, with SRAM Rival XPLR AXS group and carbon wheels for €5,499. It is also possible to purchase the frame kit for €4,499.

BMC Kaius 01 ONE. Specifications, weight, and price

• Frame: Kaius 01 Gen 2 Premium Carbon
• Fork: Kaius 01 Gen 2
• Handlebar: ICS Carbon Aero Gen2, 135 mm drop, 81 mm reach, and 12° flare
• Seat post: Teammachine SLR 01 Gen 5
• Saddle: Fizik Vento Argo X1 Carbon 140 mm
• Crankset: SRAM Red XPLR AXS 42T with power meter
• Cassette: SRAM Red XPLR 10-46 (13 speeds)
• Chain: SRAM Red
• Rear derailleur: SRAM Red XPLR AXS
• Shifters: SRAM Red AXS
• Brakes: SRAM Red AXS with 160 mm discs
• Wheels: CG39SL Carbon Tubeless Ready 39 mm
• Hubs: CG39SL for carbon spokes with Star Ratchet system
• Tires: Continental Terra Competition Race Rapid 45 mm
• Weight: 7.62 kg
• Price: €10,999