With its clean, smooth looks and some aero touches going on you'd easily think the new Argon 18 Krypton Pro is a full-on race bike. It certainly delivers on performance thanks to a low weight and plenty of stiffness, but factor in its immense comfort and slightly relaxed geometry and you'll find this is probably one of the fastest endurance machines on the market.
The rear end comfort of the Krypton is seriously like nothing I have ever ridden, even with the 25mm tyres pumped up to 100psi. Sit on the saddle to start your ride and the first thing you'll do is check that you haven't got a slow puncture because the feeling through the seat is that plush.
That isn't the amazing thing, though. After all, it's pretty simple to make a bike frame comfortable: let it flex. What the Argon 18 engineers have achieved here by concentrating on and designing the carbon fibre layup is to damp the ride without affecting all-out performance and stiffness.
Even sat in the saddle, if you push hard on the pedals whether for a short blast or a long drag down a windswept straight, the Krypton Pro responds exactly how you want it to – delivering power and acceleration without lag while still damping the high frequency road buzz.
That is what makes this thing so fast, and it gets quicker – or should I say you don't get any slower – the longer you ride it. Taking the edge off the vibrations and general road chatter means that you remain fresher and can just get on with turning those pedals for as long as you want.
I like a lot of feedback from a bike; I want to feel every minute detail of what it is up to beneath me, especially when the surface or conditions aren't great or when you are motoring downhill and likely to need to make instant and decisive inputs to keep the bike rubber side down.
Thankfully, all of this comfort hasn't taken anything away from the Argon 18. It is as sharp as a button.
If you look at the Krypton Pro from the side, you can see that the front end is much more overbuilt than the slender rear and this gives plenty of precision to the handling and it can cope with the high loads of heavy braking on descents.
When you are really giving it the beans, the Argon 18 behaves like a race bike helped along by that none-too-shabby weight of 7.66kg (16.9lb) for our Campagnolo Chorus build.
The steering, thanks to that endurance geometry, is spot on delivering a non-twitchy yet involving directness whether blasting along the flat or taking on a technical descent in the lanes.
The angular looking fork offers plenty of stiffness, too, without the slightest hint of understeer when turning hard into a tight bend, and should you have to haul on the brakes to scrub a lot of speed there is no 'dive' or chatter from flex.
At speed, the rear end still brings a lot to the party. The way it soaks up the bumps means that the whole bike feels planted, backed up by the 1,013mm wheelbase on this medium size. You can concentrate on nailing those apexes with the handlebar and let the rear end get on with taking care of business without getting bounced around on the saddle, giving the whole bike a feeling of stability.
Hard acceleration or when climbing out of the saddle sees the Krypton Pro deliver, too. The oversized bottom bracket area and chunky chainstays get the power through to the rear tyre and off you go. Again the weight, or lack of it, plays its hand here and the Argon 18 is a very confident performer in the hills.
I mentioned the carbon layup earlier, and this really is the key thing when it comes to a carbon fibre frame. It's easy to make one very stiff or very light, or both of those; it's making one that's light, stiff and comfortable that's tricky. It's why some frames at the lower end of the market can resonate and vibrate like mad over rough surfaces, making them feel a little on the plastic side.
With this new model, Argon 18 went right back to scratch and focused on this layup to deliver the comfort levels required for the Astana pro team at races like the cobbled Paris-Roubaix and Tour of Flanders, without relaxing the stiffness required by top flight cyclists.
What it's delivered is a frame weight of around 870g in a medium that still gives all of that stiffness and comfort. It's very impressive indeed.
Stiffness at the front end is also aided by Argon 18's new stem and 3D+ system which allows you to slightly adjust the stack and reach measurement by swapping out head tube extensions that give three different heights. You can see them sitting under the stem, integrated into the top tube.
This approach, according to Argon 18, gives a 5% increase of rigidity at 15mm and 11% at 30mm of height, instead of using standard spacers below the stem to achieve the same height.
The stem is also designed, along with the steerer, to completely hide the brake hoses as they leave the handlebar, giving a very clean look to the front end. If you are using electronic shifting the wires also disappear into the stem, but with mechanical setups like we have the gear cables run as standard, no doubt because the tight bend would affect shifting if they were to follow the same route.
The fork legs are also designed to improve airflow, and at the rear you have a curved seat tube to match the profile of the tyre and dropped seatstays similar to that found on the new Specialized road bikes.
The frame and fork offer clearances for up to 32mm tyres, and as you'd expect you get 12mm thru-axles front and rear plus flat mounts for the disc callipers.
The bottom bracket is press-fit, which might not be to everybody's liking, but I certainly didn't have any issues with it creaking over the test period.
As I've said, the Krypton Pro is pitched as an endurance bike, although it does sit slightly closer to the race bike end of the spectrum than many others in the marketplace.
The medium that we have has a top tube length of 558mm and a head tube length of 149mm with the smallest extension fitted, 164mm with the +15mm extension, and 179mm with the +30mm option.
Changing the extensions affects the stack and reach measurements like so:
Extension 1: stack = 589mm, reach = 388mm
Extension 2 (+15mm): stack = 594mm, reach = 383mm
Extension 3 (+30mm): stack = 608mm, reach = 379mm
Other dimensions are a head angle of 72 degrees and a seat tube angle of 73.7 degrees, with chainstays of 420mm in length.
There are six sizes available, with an XXS offering a top tube of 496mm through to the XL which goes up to 604mm.
Although our Krypton Pro test frame is draped in the latest Campagnolo Chorus components, hydraulic disc brakes and Shamal Ultra wheels, it is available as a frameset for £3,499.99. That is a fair old chunk of money, but what you are getting is a frameset that is exceptionally built and delivers the superb ride described above. Even on really rough roads there isn't the slightest rattle from internal cables or any creaks throughout the entire bike.
David Arthur was blown away by the 3T Strada frameset, and while the Krypton Pro isn't as focused on aerodynamics, both share an impressive level of performance and comfort. The 3T will set you back another £200, though.
Another frameset I enjoyed riding was the Look 795 Blade RS. It is aimed more at speed than comfort, but I certainly never felt that the latter suffered.
It's £500 cheaper than the Argon 18, but I'd say the Krypton Pro is a better all-round performer. When it comes to speed and acceleration they are very similar, but as I mentioned in the Look review, it lacks a bit of involvement so it doesn't actually feel as fast as it is. The Argon 18 definitely does.
The Krypton Pro takes it on comfort easily, although I'd be hard pressed to pick a loser when it comes down to stiffness.
Overall, the Krypton Pro is a fantastic frameset for all but the most committed of racers. That blend of forgiveness without sacrificing stiffness in the planes it's needed is a masterstroke, and not something I've come across to this level before. I'd never get bored of riding it.
One of the most comfortable frames on the market that doesn't sacrifice speed or performance
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road.cc test report
Make and model: Argon 18 Krypton Pro
Size tested: Medium
Tell us what the frameset is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about the bike?
Argon 18 says, "For us a perfect ride begins with a layup that integrates the optimal balance of weight, comfort and stiffness performance points.
"Then we add a few more criteria, like a club ride that pushes the pace and nails the climbs, maybe a rough section to reach that perfect view, a few technical twists and turns on a long descent, and a full day to max out the miles.
"We made the Krypton Pro for this: a no-compromises bike that's stable at speed, responsive under big watts, smooth after a full day in the saddle, and meant for cyclists who want to ride, ride, and ride.
"Informed by Astana Pro Team at Paris-Roubaix and ready to meet the demands of La Marmotte and L'Étape, the Krypton Pro may re-write the story of the perfect ride."
Argon 18 has achieved this comfort/performance mix by getting the carbon fibre layup spot on.
State the frame and fork material and method of construction
Both the frame and fork are manufactured from carbon fibre.
Tell us about the build quality and finish of the frame and fork?
The overall build quality looks to be faultless, as does the finish.
Tell us about the geometry of the frame and fork?
The geometry is aimed at an endurance setup but it is still quite on the racy side when you look at the top tube length versus the head tube length.
Full details are here.
How was the bike in terms of height and reach? How did it compare to other bikes of the same stated size?
The stack and reach figures can be adjusted by way of the three different head tube extensions, which can make the bike more or less aggressive. See the full details in the review section above.
Riding the bike
Was the bike comfortable to ride? Tell us how you felt about the ride quality.
Brilliantly comfortable. Argon 18 has done a great job of delivering a very comfortable frame without massively sacrificing stiffness.
Did the bike feel stiff in the right places? Did any part of the bike feel too stiff or too flexible?
Yes, it is stiff where it needs to be.
How did the bike transfer power? Did it feel efficient?
Power transfer is excellent, surprisingly so considering how comfortable the rear end is.
Was there any toe-clip overlap with the front wheel? If so was it a problem?
How would you describe the steering? Was it lively neutral or unresponsive? The lively side of neutral.
Tell us some more about the handling. How did the bike feel overall? Did it do particular things well or badly?
It feels almost as sharp as a race bike, just backed off a touch to reduce the twitchiness.
How did the build components work with the frame? Was there anything you would have changed?
The Campagnolo groupset and wheels plus the carbon handlebar from Zipp is exactly the type of kit that suits the Krypton Pro. It's the type of build I'd aim for. I'd say a starting level of Shimano Ultegra mechanical would work with the frameset too.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
You can get some very comfortable and stiff framesets for half this money from the likes of Canyon and others, but I've never found such a perfect balance as I did on the Krypton Pro. Compared with top end frames, because that's what it is, the Argon 18 it holds its head high.
Did you enjoy riding the bike? Yes
Would you consider buying the bike? Yes
Would you recommend the bike to a friend? Yes
Use this box to explain your overall score
It's a big chunk of money to spend on a frameset, but the engineering and resulting ride is top notch, especially for those who like to ride at speed in comfort.
About the tester
I usually ride: This month's test bike My best bike is: B'Twin Ultra CF draped in the latest bling test components
I've been riding for: Over 20 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: time trialling, commuting, club rides, sportives, fixed/singlespeed
With 20 years of road cycling and over 150,000 miles in his legs it's safe to say Stu is happiest when on the bike whatever the weather. Since writing his first review for road.cc back in 2009 he has also had a career in engineering including 3D-CAD design and product development, so has a real passion for all of the latest technology coming through in the industry but is also a sucker for a classic steel frame, skinny tyres, rim brakes and a damn good paintjob.
His fascination with gravel bikes is getting out of control too!