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.
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 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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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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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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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 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.
|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|
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)
- Seatpost: Kaius 01 Premium Carbon D-Shaped Seatpost – 15mm Offset (0 offset is available)
- Saddle: Fizik Vento Argo 00