There’s a certain sweet satisfaction that comes along with emphatically dropping someone who is riding a vastly more expensive bike than what you’re on. As they say, it’s the legs and lungs that ultimately do the talking. At less than the cost of even average wheelsets these days, the Kinesis Aethein certainly qualifies as a budget race machine. But it’s hardly lacking in capability, and is equipped with more than enough modern aluminum technology to ensure your legs and lungs are heard loud and clear.
Kinesis has long been a fixture in the bicycle industry as a powerhouse OEM frame and fork manufacturer, working primarily in mid- to upper-end aluminum, all with a strong focus on value. After struggling to get its brand name in the front of people’s minds, however, Kinesis eventually decided it needed a stronger consumer presence. Of all the major international markets, the United Kingdom is arguably the one most sensitive to price, so the company embarked on a project in the late 1990s to develop Kinesis-branded frames specifically for cost-conscious British riders.
Since then, the “Kinesis UK” brand has become synonymous with excellent performance at reasonable prices, along with feature sets that appeal to privateers who either need to race and train on the same machine — in all weather conditions — or anyone looking for a good bike that won’t break the bank.
Kinesis UK may have been originally created to cater to a specific market, but the reality is that a much wider range of cyclists can benefit from the same mindset: bikes don’t need to be expensive to be good; a little bit of rain doesn’t automatically equate to a “rest day” at home; high-performance machines shouldn’t be considered disposable; and even bikes meant for racing should still have room for bigger tires.
Turning aluminum into plastic
The Aithein is Kinesis UK’s latest road frameset, smoothly TIG-welded from a custom aluminum tube set the company dubs, “Kinesium” — essentially a proprietary 6000-series alloy similar to Easton Scandium, but using titanium instead of scandium as an additive to refine the material’s grain structure for improved fatigue life, strength, and formability.
Kinesis puts that formability to good use on the Aithein, especially at the “AntiGravity” seat tube, which starts with a round 35mm-diameter up top, transitions to a rectangular shape around the front derailleur tab, and then flares outward at the base to a whopping 55mm-wide flattened pentagon in an effort to boost drivetrain stiffness.
The wider and more rectangular profile that the seat tube takes at its base helps keep the bottom bracket area from swaying under load.
All of this is done using the company’s “SuperPlastic Forming” technology. According to Kinesis, SPF is similar to conventional hydroforming in that a round tube is forced to expand outward against a steel mold, but it uses compressed air instead of pressurized fluid. Moreover, the higher temperatures used in SPF makes the tubing more malleable, which allows for thinner walls, more complex shaping, and sharper creases than what is normally available through hydroforming.
Tube shaping on the Aithein is more modest elsewhere, with a smoothly tapered 1 1/8-to-1 1/2″ head tube, a medium-diameter down tube with a subtle teardrop profile up front and slight ovalization at the PF86 press-fit bottom bracket shell, and average-sized (for aluminum) single-bend chainstays that closely follow the sides of the wheel for extra heel clearance. Whereas tiny seatstays are all the rage, the Aithein’s are roughly the size of your index finger, and round and straight from end to end.
The chainstays are heavily curved for heel clearance.
Cable routing is unashamedly external, but it’s done well with head tube-mounted derailleur housing stops that put an end to paint rub, and are also split and milled-out for easier maintenance and at least the air of gram-shaving. The PF86 press-fit bottom bracket shell is reamed (but not faced) after welding and heat treating for a secure fitment with the bearing cups, and the seat tube is similarly reamed to remove seatpost-scarring burrs.
Actual weight for my 53cm frame was 1,248g including the seatpost collar and replaceable rear derailleur hanger. The matching fork added another 333g, with the steerer trimmed to 195mm and without the included compression plug. Kinesis also offers the Aithein with an anodized finish, which would lop off another 100-150g given my test sample’s thick coat of pearlescent orange paint.
Built up with Shimano’s latest Dura-Ace R9100 groupset, matching Dura-Ace C24 shallow-profile carbon-and-aluminum clincher wheels wrapped with 25mm-wide Vittoria Open Corsa CX tires, and a smattering of finishing kit from PRO, total weight came out to an impressive 7.36kg (16.23lb) — and that’s including pedals and bottle cages.
Lighting up the road
I’ll freely admit to being smitten by carbon fiber superbikes over the years, but the continuing advancement of aluminum technology — and the universal appeal of more attainable pricing — has drawn me back to metal. I’d also be lying if I said that the Aithein matches the performance of a good carbon frame, pound-for-pound. Unquestionably, it’s a different animal altogether, but hardly a disagreeable one.
Kinesis pegs the Aithein as, “ready to ride fast and take on your local crit league” — a description that conjures images of lightning-quick reflexes, a propensity to dive into corners, and an eagerness to shoot out of them under power. My experience on the road, however, supported the former part of that statement, but not so much the latter.
You can look for, but won’t find, any smidgen of aerodynamic shaping on the Kinesis Aithein. From afar, the frame looks a bit old school, but there’s quite a bit advanced shaping incorporated into the design.
The Aithein’s slightly taller-than-average 68mm bottom bracket drop and impressively stout rear end is certainly criterium-friendly, providing a touch more cornering clearance while pedaling than usual, and effectively harnessing your power with minimal tail wag. Things aren’t quite as rigid up front given the more modest tubing diameters, though, and there’s a touch of wiggle when you wrestle the bars back and forth in a sprint or climb. Nevertheless, lay the power down in reasonably smooth fashion and the Aithein is more than up to the task of quickly building up speed.
It’s only in terms of handling that the Aithein somewhat disappoints — and even then, it’s only due to expectations. While the rear end is suitably short with its 405mm-long chainstays, the front end is oddly long for a self-professed crit bike, and better suited for fast cruising than bumping shoulders through a bend. My 53cm test sample, for example, features a comparatively generous 985mm wheelbase and 390mm reach — more than 20mm and 10mm longer than a 52cm Specialized Allez DSW SL, while also sporting a slacker head tube angle.
The tapered head tube is clean and purposeful, without the overabundance of shaping that can sometimes accompany a composite chassis.
That longer front center makes for excellent high-speed manners and unflappable stability on descents, but also a tendency to drift toward the outside of corners. Manhandling the bars with a more aggressive lean on the inward side of the bars helps when initiating turns, but even so, the Aithein wasn’t quite the apex-seeking rocket that I had expected.
Downsizing to a 50cm may have helped in some regard, but also reveals a shortcoming in the Aithein’s sizing scheme in that reach doesn’t scale with size. That 51cm would actually have been 3.5mm longer, and in fact, the Aithein’s cockpit lengths are quite long across the board. Even the smallest size, 47cm — one recommended for riders standing just 150-160cm (4-foot-11 to 5-foot-3 inches) tall — still sports a proportionally gargantuan 386mm reach.
This graphic is easy enough to spot, but more impressive is the fact that Kinesis bothered to hide the “2” on the underside.
According to Kinesis UK marketing man Bruce Dalton, this is something the brand will be rectifying with the next-generation Aithein (due sometime next year), but in the meantime, inspect the geometry chart carefully, and choose wisely.
Ride quality on the Aithein was more like what I had anticipated with the two sets of wheelsets I used during testing: Shimano’s latest Dura-Ace C24 carbon-and-aluminum clinchers with 25mm-wide Vittoria Open Corsa CX tires and butyl tubes at 80-90psi; and Easton’s new EA90 SL wide-profile aluminum clinchers shod with 24mm-wide Specialized S-Works tubeless tires at 70-80psi. It damps road buzz and chip seal pretty well, but nonetheless provides a more tactile, direct, and communicative read of the road surface than you usually get out of carbon — rougher-riding than the VYNL Road aluminum frameset I tested earlier this year, but not as harsh as the more hard-edged Specialized Allez DSW SL.
Whereas many frames are built with spindly seatstays in an effort to smooth out the ride, the Kinesis Aithein goes with relatively large-diameter tubes that take a straight path from end to end. Coupled with the oversized seatpost, the ride quality is quite firm.
Even so, between the large-diameter seatstays, the oversized seatpost, and the minimal seatpost extension owing to the Aithein’s more traditional top tube slope, bigger bumps are best anticipated by getting your butt off of the saddle. In keeping with the Kinesis UK design ethos, the Aithein has plenty of room for 28mm-wide tires should you need a bit more cushioning, but keep in mind that there are no fittings for fenders regardless of what size rubber you install. Kinesis UK may be designing its bikes with British riders in mind, but in the case of Aithein, this is a machine that is billed as a pure racer.
Aesthetically, the Aithein is a bit of a mixed bag. The smooth weld beads and unfettered lines lend the frame a clean, purposeful, and businesslike look well-suited to the bike’s workhorse aspirations. The sparkly metallic orange paint on my sample is positively radiant in bright sunlight, too, and a refreshing departure from the sea of blacks, greys, silvers, and reds that usually populate modern road bikes.
As good as the Aithein is on the road, Kinesis definitely needs to work on its graphics and branding. “RaceLight” is neither the make nor the model, but rather the family of bikes to which the Aithein belongs. It’s an odd choice to dominate the down tube.
However, the graphics are curious at best. The “Kinesis UK” badging is limited to tiny print on the top tube (almost as if even the company itself isn’t wholly confident in the brand’s appeal), and the model name is written in only somewhat larger script just ahead of the seat cluster. Center stage is instead given to the frame family to which the Aithein belongs, and the down tube is plastered with a giant “RaceLight” decal, which strikes me as rather odd, and not entirely appealing visually.
Overall, the Aithein is an easy bike to like, and one that’s tough to criticize too harshly given its wallet-friendly price tag; after all, there’s certainly more room for error at this end of the cost spectrum. Nevertheless, I’m eager to see what Kinesis has in store with the second-generation Aithein, which, in addition to the revamped sizing scheme, will perhaps also incorporate a more liberal infusion of the company’s impressive SPF tube shaping technology.
The Kinesis Aithein is more of a budget machine in terms of its asking price, but its performance on the road makes a strong case that you don’t really need to spend more.
The welds are big but fairly smooth, and they’re further masked by the vibrant paint.
The so-called “SuperPlastic Formed” seat tube takes on a wide, rectangular profile down by the PF86 press-fit bottom bracket shell.
Press-fit bottom brackets aren’t as easy to service as threaded ones, nor are they as easy to keep quiet. Metal frames with press-fit shells generally work better than carbon ones, though, especially when they’re machined after welding and heat treated, as is done on the Kinesis Aithein.
The milled-out housing stops on the Kinesis Aithein are nice, high-end details.
The external cable routing may disappoint some, but it’s very straightforward to set up and service.
Included with the Aithein’s modest asking price is a full-carbon fork with matching graphics.
Depending on your location, it may be difficult to source a replacement hanger for the Kinesis Aithein if and when needed.
The Kinesis brand name is restricted to tiny lettering on the top tube.
The bridgeless layout and heavily massaged shape makes for extra tire clearance. Kinesis officially rates the Aithein for 28mm-wide rubber.
There’s also ample room through the fork crown for 28mm-wide tires.
The smart housing stop location keeps the housing from rubbing on the paint.
The chainstays aren’t particularly big, but yet the rear end of the Kinesis Aithein is certainly stiff enough.
Dropouts are straightforward, but neat and compact.
The seatpost isn’t normally included, but Kinesis included one for our tester, anyway. This two-bolt carbon job is decent enough, but given the oversized diameter and only slightly sloping top tube, my recommendation would be for a high-end aluminum seatpost like a Thomson Masterpiece.
The Kinesis Aithein may be made in Asia, but that doesn’t mean it’s made by robots. Check out the cutouts in the seatpost collar, too.
What’s an “Aithein”, anyway? Roughly translated, it means, “to burn or ignite.”
WRAP-UP
- Outstanding performance-to-cost ratio
- High-quality finish work
- Room for 28mm-wide tires
- Available disc brake option
- Somewhat rough ride
- Handling traits not as expected
- Funky sizing scheme
