Bike of the Week | The BMC Kaius is a lightweight gravel race bike with a super-narrow aero handlebar

Swiss brand’s new lightweight, aerodynamic gravel racer 

BMC Kaius gravel bike against a rural background

Launched in September 2022, BMC’s Kaius has arrived at BikeRadar HQ for testing.


The Kaius is a minimalist, lightweight and aerodynamically optimised gravel race bike, very much in the vein of Specialized’s S-Works Crux or Cervélo’s Áspero 5.

It occupies the complete opposite end of the spectrum compared to the brand’s URS, which uses suspension and elastomers to offer a bump-taming ride.

Let’s take a closer look at this race-oriented gravel bike.

A Swiss frame approach

The Kaius borrows heavily from the Teammachine.
Kaden Gardener / Our Media

The Kaius takes clear inspiration from BMC’s road race bike, the Teammachine SLR01, sharing a visually similar sculpted head tube, oversized down tube and angular, dropped seatstays.

BMC says the Kaius uses high-modulus carbon in certain areas of the frame to achieve an equilibrium between stiffness, power transfer and minimal weight. The brand also says it has reinforced some areas of the Kaius’ frame to help it withstand tough off-road riding.

BMC claims a low 910g frame weight in a size 56cm, with the fork adding a further 400g.

The Kaius features the brand’s Aerocore bottle cages, also found on the Teammachine. These integrate into the down tube and seat tube, with the aim of smoothing airflow.

The stealth dropouts BMC introduced on the Teammachine carry over to the Kaius. This sees the thru-axle insert bonded in place. The insert isn’t visible from the outside face of the driveside chainstay or fork leg, resulting in a particularly clean aesthetic.

No thru-axle insert in sight…
Kaden Gardener / Our Media

Like other bikes in BMC’s range, the Kaius sticks to a BB86 bottom bracket standard.

The Kaius has 700c gravel wheels and clearance for 44mm gravel bike tyres, which is similar to the 45mm tyre clearance of the Àspero 5 but not as generous as the 47mm tyre clearance of the S-Works Crux.

It’s a BMC through-and-through.
Kaden Gardener / Our Media

In a nod to versatility, the Kaius has top tube mounts for a bento box and can accept either 1x or 2x drivetrains.

It is compatible with a dropper post and can be used with BMC’s ICS MTT suspension stem.

What is Bike of the Week?

Every fortnight, we’ll bring you a detailed first look at one of the latest bikes (or framesets) to arrive at BikeRadar HQ – from road to commuting, gravel to enduro, and anything in between.

This is our chance to introduce the bike and everything that makes it unique before hitting the road or trails.

Head to our Bike of the Week hub for previous editions.

A clean front end

Like the majority of BMC’s performance bikes, the Kaius uses an integrated bar-stem. Called the ICS Carbon Aero Cockpit, the one-piece bar and stem weighs a claimed 315g and hides the bike’s hydraulic hoses.

Unlike BMC’s road handlebars, the Kaius’ bar has 12.5-degree flare, which means it measures 36cm along the top and 42cm at the drops. The design’s narrow profile is said to improve aerodynamics and comfort.

A tasty spec list

Our test bike is the range-topping Kaius 01 One in a size 58cm. It retails for £11,350 / $11,999 / €11,499.

The 01 One comes equipped with a SRAM Red AXS XPLR groupset. The 10-44 cassette is paired with a 42t crankset, and 160mm disc brake rotors are specced front and rear.

The Cinturato Gravel H is designed for hard-pack surfaces.
Kaden Gardener / Our Media

Zipp’s 303 Firecrest wheels have proved a popular option on many gravel bikes recently, and they’re shod with Pirelli Cinturato Gravel H tyres.

The finishing kit comes courtesy of BMC, with the aforementioned bar-stem and a proprietary D-shaped seatpost. The saddle is a Fizik Vento Argo 00.

A Fizik Vento Argo 00 saddle sits atop the proprietary seatpost.
Kaden Gardener / Our Media

All-in, the bike weighs in at 7.71kg without pedals.

There are two other models in the range, — the Kaius 01 Two and 01 Three. The 01 Three is the entry-level Kaius, retailing for £5,699 / $5,999 / €5,499. It has a SRAM Rival eTap AXS groupset, using the 2x Wide variant, and BMC’s CRD-400 40mm wheels.


The 01 Two sits in between at £8,350 / $8,999 / €8,499 and is equipped with a SRAM Force AXS Wide groupset and Zipp 303S wheels.