Carbon fiber is known for its incredible stiffness and strength-to-weight ratio. The bicycle industry leverages these properties to create the most energy-efficient and lightweight machines possible. However, these properties also mean carbon bikes tend to be unforgiving and harsh, especially race bikes. Speed trumps comfort. Or does it?
Cannondale launched the SuperX gravel race bike today, and instantly, the images of frame tubes made me think, “WTF?” I’m familiar with carbon flex-stay mountain bikes. These single-pivot, short-travel mountain bikes supposedly “articulate” the rear axle by flexing frame tubes in the rear triangle. Yes, these bikes can be fast, but I’ve never really felt that the frames provided that much compliance.
But one look at the frame visuals for the SuperX revealed that Cannondale took the flex-stay paradigm to the extreme. I’ve never seen frame tubes smashed so flat in the name of defying material properties. Maybe the brand’s extreme efforts to coax carbon to bend will pay off with enhanced vertical compliance to gain more comfort and speed.
Cannondale SuperX ‘Flat’ Tubes
The most “WTF” visual is the one of the bottom bracket junction. The seat tube is impossibly flat. I cannot recall another frame of any material with a seat tube this thin.
This “let’s bend carbon” logic also appears in the flex zones in the top tube and rear triangle. These flex points are meant to coerce the rear triangle to rotate forward to afford vertical give.
If you look at where each flattened section is and imagine the rear axle wanting to move upward, you can “see” the rotation if the frame indeed bends at the flex points. That’s Cannondale’s theory, anyway.
Other Cannondale Super X Features
Greater vertical compliance is an advantage, but racers won’t accept it if it comes at the cost of other attributes. Cannondale made similar improvements in other areas to add to the SuperX prestige.
Weight
Flexy or not, racers want their rigs to be light. And Cannondale hit the bull’s-eye with the SuperX gravel bike; it claims that a 56cm painted top-end LAB71 frame registers under 900 g, which is amazingly light for a gravel bike frame.
Cannondale also claims that its uber-spec SRAM RED XPLR AXS-equipped version weighs only 16.3 pounds, with sealant, no bottle cages, and no pedals. Only one other gravel bike has bested this featherweight number that GearJunkie has tested, and that’s the comparably equipped Specialized S-Works Crux.
The LAB71 SuperX frame is 100 g lighter than the outgoing SuperSix Evo CX/SE frames and about 100 g lighter than other versions of the Cannondale SuperX.
Cannondale Super X Frame Geometry
Cannondale stuck to its guns on the geometry, roughly matching the outgoing SuperSix EVO and SE bikes. Generally, the SuperX leans more toward road bike on the road-to-gravel spectrum.
Relatively slack head tube angles are mated to moderate trail figures. This makes the front more controllable in slick conditions while retaining agility.
The stack and reach are also moderate, with the numbers slanting away from “progressive geometry” (longer reach/shorter stem) and more toward road bike geometry.
Tire Clearance
Tire choice and air pressure dominate chatter at the start line of most gravel events. Both massively affect the bike’s performance and comfort. The trend toward wider, higher-volume tires is strong, so having the frame clearance to at least have these options is a serious consideration.
Cannondale gave the SuperX enough clearance for a 48mm tire in the rear and a 51mm in the front. This isn’t a large amount of clearance by today’s standards, especially for more adventure-oriented bikes. I would say it’s only adequate for race bikes. Cannondale delivers the SuperX with 40mm tires, which does leave room for some mud build-up.
Internal Routing on the Cannondale SuperX
It’s hard to resist, and Cannondale joined the fray; routing is fully internal, through the headset, on the SuperX, much to the dismay of many.
However, the brand took steps to ensure housing doesn’t rub tunnels into the carbon steerer tube. A triangular steerer tube affords more room for housings and hoses, and an Aramid wrap protects it from abrasion.
Frame Mounting Points
Cannondale aims the SuperX at racing and, by its logic, strips the frame down to minimal attachment points. There is no trendy internal storage compartment and no bag mounts other than a somewhat hidden top tube bento box mount.
Other than that, you get the usual pair of water bottle cage mounts. That’s it.
Aesthetics
Cannondale graced the SuperX with a more classic appearance. Most modern bike frames have a steeply sloped top tube. This design allows more of the seat post to extend out of the frame, theoretically inducing more seat post flexion, enhancing comfort and control.
Since Cannondale engineered the flex to occur within the frame, it doesn’t rely as much on seat tube flexion. The horizontal top tube lends a more classic look to the SuperX and makes shouldering it a lot easier for those who enjoy the heinous burn of cyclocross.
Closing Thoughts: Cannondale SuperX
If Cannondale’s radically flattened frame flex zones work, the SuperX could be an incredible gravel bike, for racing or not. To have a featherweight, efficient carbon gravel bike that is still comfortable can seem unattainable. The S-Works Crux came closest (in my eyes) in achieving this dichotomy of characteristics, but maybe the SuperX can nudge into its territory.
The brand offers three versions of the SuperX, so the potential magic ride is not just for the wealthiest. Yes, the high-zoot LAB71 lists at a shock-inducing $15,000, but the 3 has an approachable MSRP of $4,200.
Cannondale has a history of nonconformity, sometimes to great success, sometimes to dismal failure. But at least it consistently butts up against the status quo. And when its “radical” approach works, it’s worked wonderfully.
I will diligently pursue a test sample of the SuperX to see if the latest weird AF Cannondale approach breaks the mold in a good way.
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