The BMC Kaius 01 One offers a unique solution to the puzzle of winning a gravel race. It won’t be for everyone but it’s a clever way to offer real aero gains. Just be sure the price makes sense for the riding you want to do.
Pros
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Dropper post compatible
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1x and 2x compatible
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Comfortable narrow bars
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Aero at every detail
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Stable geometry
Cons
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Limited build options
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Expensive
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Gravel racing seems to be capturing the imagination of the consumer, and because of that, the bike industry too. While our list of the best gravel bikes still has a good amount of diversity, the wild designs that marked the earlier chapters of modern gravel cycling are starting to fall away. In their place, brands are starting to offer a group of bikes that come remarkably close to road bikes but with greater tyre clearance. One of those bikes is the new BMC Kaius O1 One, well and truly aiming for a spot in the best gravel race bikes list.
If you are looking for a bike designed to move as quickly as possible in a gravel race then there's no doubt this one is on your short list. Given that it's meant for gravel racing, what better way to test it than with a gravel race? I flew across the country and spent a long weekend testing and racing the BMC Kaius 01 One at Big Sugar Gravel 2022, the last Life Time Grand Prix race of the year. If you are looking for a bike that's perfect for gravel events all over the world, keep reading to see what I thought of it.
This is the view of Kaius 01 One that is sure to capture headlines but there's more to the bike than narrow bars (Image credit: Josh Ross)
Design and aesthetics
As I said in the intro, I rode the BMC Kaius 01 One at the Big Sugar gravel race. I was there a few days early and I rode each day as much as I thought I could stand without being too tired on race day. Every single time I took the bike out I got stopped about it. At one point I had a class of secondary school kids surround me with non-stop questions. The design of this bike will grab attention.
Part of that is the paint. There are three builds available and each one brings a unique colour scheme. At the top of the lineup is the One (to be clear it's the Kaius 01 and the build is the One), and that version gets a crisp, clean, white scheme. It's a white that trends towards blue and the bit of blue/green gradient on the fork only emphasises that. Against the autumn colours of the southeastern United States, it's as attention grabbing as anything could possibly be.
The white graces more than just the frame and fork though. Choose the range topping One build and the integrated cockpit uses the same, gleaming, high-gloss paint. However, it's not only the paint that brings attention to the cockpit. Get a little closer, though it doesn't take much, and you might notice that there's not much room between the SRAM RED hoods.
While most brands seem to be pushing handlebars wider and wider, BMC serves up a set of bars that are only 36cm wide at the controls. The frame has options for six sizes ranging from 47 up to 61 but the cockpit is the same across the sizes. If you want wider, take advantage of the 12.5-degree flare and put your hands down into the drops where it goes as wide as 42mm. If you want to go even a little narrower, the controls have a bit of an angle that puts the peak of the tops inside even the 36mm width at the measurement point on the hoods.
The bars have a 12.5 degree flare and stretch out to 42cm at the drops but the top of the controls are even narrower than the measured 36cm (Image credit: Josh Ross)
The narrow bars are a bold design choice but they really only scratch the surface of what makes the bike what it is. If you stay at the surface level a bit more, you'll find that everything about the Kaius 01 is aero-optimised. The most obvious detail of that might be the lack of cables at the front end and the aero shaping of the tops. Check behind the fork and you'll find a detail to help smooth the airflow as it contacts the downtube and the included Aerocore Bottle Cages do more smoothing down lower. These are all details that are almost pedestrian at this point though.
Keep looking and you will keep finding aero details. The seat post binder is, of course, a hidden bolt and there's a collar that smooths the connection to the top tube. At the front, there's the ubiquitous aero top cap for the steerer tube but there's also a cover for the stem bolts. When it's time to remove a wheel, you'll find that BMC has been so thorough that thru-axles are even limited to a single opening with the other side being completely smooth. Unfortunately, given the obvious effort, there are no quotable numbers for watts saved, but the bike is more than just aero.
The narrow handlebars are aero but they also play into a bigger story about the geometry of the Kaius 01. Narrow bars make for faster steering as does the integrated 90mm stem on a size 54 bike. Given that fast steering isn't really an ideal trait on a gravel race bike, BMC pairs the cockpit numbers with a big bottom bracket drop as well as a big trail number. It's modern, progressive, gravel bike geometry but the use in this context is somewhat novel.
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At the top level, the only option is a 1x groupset but the frame will take 2x without issue(Image credit: Josh Ross)
There is integrated protection on the chainstay that's obvious but there's also invisible protection in areas exposed to rocks and shocks to give riders peace of mind(Image credit: Josh Ross)
With a 40mm tyre there's not a lot of room and max clearance is 44mm(Image credit: Josh Ross)
Specifications and build
BMC only offers three builds in total and if you want the top tier, there's only one. The frame itself uses internal cable routing but at the top tier there are no gear cables anyway. The hydraulic brake cables will stay out of the wind but the SRAM AXS groupset means no need to thread even an electronic cable through the bike. SRAM RED is the groupset offered and gearing is a 1x configuration with an XPLR 10-44 rear cassette and a 42-tooth front chainring. There is also the already mentioned one piece ICS Carbon Aero cockpit, a Carbon D-Shaped seatpost, and a Fizik Vento Argo 00 saddle to round out the touchpoints. The last notable piece of the build at this level is a set of Zipp 303 Firecrest tubeless wheels.
If the one-piece bar and stem aren't for you, you'll need to step down to one of the two lower models. Both options use a system to route any cables through the headtube but they are also both two-piece systems in a more conventional size depending on frame size. Model Two sticks to carbon while model Three moves down to an aluminium bar.
Along with the change in the bars the expected drop in groupset level and included wheels happens as well. Everything stays SRAM only but both the Two and the Three get 2x systems. Model Two features Force AXS Wide 43/30 upfront and a 10-36 in the rear while Three sees Rival AXS with the same gearing. For the wheels, the least expensive model uses the CRD-400, still carbon, and keeps the same 40mm depth as the Firecrest 303 while the Two gets Zipp 303 S wheels that are 45mm deep.
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Look deeper than the stack and reach numbers because they don't tell the story(Image credit: Josh Ross)
I would have benefited from a zero setback seatpost which is available if you need it(Image credit: Josh Ross)
In a trend I'd like to see more of, all the adjustments for the saddle thread from the bottom(Image credit: Josh Ross)
The cockpit hides all the cables and mounting is only possible via the included outfront mount(Image credit: Josh Ross)
The D-shaped seat post adds compliance through flex(Image credit: Josh Ross)
The top model includes Zipp Firecrest 303 40mm carbon wheels(Image credit: Josh Ross)
Performance
The BMC Kaius 01 One is a bike that draws you to get lost in the details. What is modern progressive geometry and why does the bike feel the way it does? It's something I desperately want to study and explain but ultimately it doesn't matter. If you only look at the reach and stack numbers you will not understand how this bike feels to ride. It's not a road bike at all, it's a gravel bike and it feels like that.
It's controllable and pointable over rough and rocky surfaces. When you need to pick a line and stick to it you can but it's not twitchy. There's enough built-in compliance between the seat tube, the seat post, and a 44mm max tyre so that you can find comfort to cover the big days. There's also enough stiffness so that the Kaius responds when you ask it as well as enough to make sure you remember that it's still a race bike.
If you care about weight in a gravel bike, and for a race bike that makes sense, it happens to be a pretty light bike as well. BMC quotes 1.785 kg for the frame, fork, seatpost, and cockpit and while I wasn't able to weigh the complete bike, it handles as you'd expect for a bike of this calibre. Zipp 303 Firecrest wheels are relatively light and the complete SRAM Red AXS 1x groupset is more than competitive as well. There are lighter bikes out there but it's unlikely the bike is a limiting factor on a hill.
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A collar smooths the airflow where the seat post meets the top tube(Image credit: Josh Ross)
There's also aero shaping on the downtube behind the fork(Image credit: Josh Ross)
The headtube is short but not overly narrow(Image credit: Josh Ross)
Those are all the ways that it's a good gravel bike in general though. What makes the Kaius 01 One that I rode unique is that it's an aero bike and BMC approaches that differently. The rider on a bike contributes more to the aero profile than any other single component and that’s where the narrow bars come into play. It’s a smart way to leapfrog other aero bike designs when all the aero tricks have already been played. The challenge is making it work on a gravel bike that needs stability and that’s where the geometry tricks make their mark. The combination of geometry that works to slow steering with a bar and stem combo that speeds up steering leads to an aero gravel bike that handles the way you want it to.
It wasn’t until the end of the race that these concepts really hit home though. The first 128km or so of the race was moderately rough and seemed to be a constant up and down. As I said above, the bike handled like I expected it to. In particular, I found it easy to get off the saddle and over the back wheel to descend and I liked climbing with it although the narrow bars don’t work well for climbing on the tops. Then the course changed.
With around 40km to go the road started to spend a lot less time going up and down and the trees began to disappear. With nothing but open fields and straight roads, there was no break from the wind and I found my happy place with the Kaius. Up until then I was doing fine with a decent bike but I do my best work down low and into the wind. In this situation, the BMC Kaius 01 is a perfect partner. The narrow bars, and the angle of the hoods, lend themselves to holding the tops of the controls and the bike feels fantastic at the top of a fairly steady state zone three effort. If you want to try and lead a solo breakaway late in the race there might not be a better option for a gravel bike.
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The rear cassette is a wide range 10-44 and it sits behind a rear junction with no break in it for the end of the thru-axle(Image credit: Josh Ross)
The front fork features the same smoothing on the outside of the thru-axle(Image credit: Josh Ross)
There's even a cover for the stem bolts(Image credit: Josh Ross)
BMC uses the same bottle cages on a variety of their road bikes and despite being called integrated, they bolt on like any other bottle cage(Image credit: Josh Ross)
Verdict
The BMC Kaius 01 One is perfect for me because I like to ride a certain way. To be specific, I’m a small person who loves to do solo efforts into the wind with my hands on the top of the hoods. It feels heroic and this is a bike that only adds to the feeling. I also happen to love riding SRAM 1x on a gravel bike. In a way that’s pretty specific, and that’s the challenge, but BMC may have also answered a question a lot of people didn’t know they were asking.
Gravel racing has matured a bit. There is a way of designing courses and a way of racing them that’s becoming less unique. The situations that many of us find ourselves in when participating in a gravel race aren’t that unique anymore. There’s no definitive right tool for the job but BMC is offering an approach that will make sense to some even if it doesn’t make sense to everyone. There is one more challenge though and that comes down to price.
The price of the One build in the Kaius 01 isn’t an outlier. You can find competition from other big-name established companies. Specialized has multiple bikes that compete at this level, as does Trek. It’s worth noting though that the prices at the top compete with some full custom bikes. Make sure you consider what is going to be the best experience with a bike before putting down the money on something off the shelf.
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Testing scorecard and notes
Design and aesthetics
There’s nothing to fault here. This is an innovative way to look at adding aerodynamics beyond what is possible with only frame details.
10/10
Components
SRAM AXS means no cables and easy to charge batteries while 1x with a wide cassette is what I agree makes the most sense for gravel racing. Some will disagree but there’s no corners cut.
10/10
Performance, handling and geometry
There is a limit to what you can do with this bike. The geometry tricks make sense for gravel racing and for road but don’t expect to get too technical.
8/10
Weight
Lighter than many options but there are options in this weight category and there are lighter options available.
8/10
Value
There are other options in this price range from other big names but you can also find a long list of incredible bikes at a better price. It’s so expensive you could even go full custom without blowing the budget.
5/10
Overall
Row 5 - Cell 1
82%
Tech Specs: BMC Kaius 01 One gravel race bike
Price: $11,999 / €11,499
Frame: BMC Kaius 01
Size: 54
Weight: 1.785 kg for the frame, fork, seatpost, and cockpit (as reported by BMC)
Groupset: SRAM AXS RED
Crankset: SRAM AXS RED 40T
Cassette: SRAM Force AXS XPLR XG-1271 10-44T
Wheels: Zipp 303 Firecrest
Tyres: Tested with Pirelli Cinturato Gravel M - 40mm (max clearance 44mm)
Brakes: SRAM Red eTap AXS HRD, Centerline X Rotors (160/160)
Bar/stem: ICS Carbon Aero, One-Piece Full Carbon Cockpit (36cm with a 90mm stem)
Josh hails from the Pacific Northwest of the United States but would prefer riding through the desert than the rain. He will happily talk for hours about the minutiae of cycling tech but also has an understanding that most people just want things to work. He is a road cyclist at heart and doesn't care much if those roads are paved, dirt, or digital. Although he rarely races, if you ask him to ride from sunrise to sunset the answer will be yes.
Height: 5'9"
Weight: 140 lb.
Rides: Salsa Warbird, Cannondale CAAD9, Enve Melee, Look 795 Blade RS, Priority Continuum Onyx
