Alchemy is a high-end American boutique brand with a unique spin on rear suspension. Its short-travel Arktos ST 29er boasts top-tier build quality and stunning industrial design, plus its bikes being a rarity on these shores will please those who like to stand out from the crowd in an age of lookalike mountain bikes.
Alchemy Arktos 29 ST frame
At the heart of the swoopy, 120mm-travel carbon chassis is Alchemy’s ‘Sine’ suspension system, which is essentially a twin-link design, with the arcing lower link neatly stashed inside the seat tube.
Its name derives from the leverage curve resembling a sine wave. The shock rate is initially regressive, for superior bump absorption and climbing traction, then progressive around the sag point, for support in turns and to resist wallowing.
It becomes regressive again for the last 15 per cent of the stroke, to allow use of all the available travel and reduce chain growth.
The chunky, one-piece mainframe gets extra ‘pre-preg’ carbon layers around the head tube and bottom bracket, plus underbelly protection, but no bottle mounts.
A fully-triangulated rear triangle helps keep things stiff. The rear stays pivot on a huge, forged-alloy upper rocker link and big bearings, both of which contribute to a mega-solid feel, especially for such a short-travel rig.
While the low-ish bottom bracket and steep-enough seat angle offer a decent riding position, the reach (485mm is the longest offered) and head angle (66.1 degrees) are more conservative than on many new-school trail bikes.
The wheelbase – sub-1,200mm on my large test bike – is shorter than most too.
Alchemy Arktos 29 ST kit
The stout, 140mm-travel Fox 36 fork with GRIP2 damper excels at way more than just mile munching, and this top-end unit also uses the latest shorter (44mm) offset for a more stable steering feel.
Out back, the Fox DPX2 shock is also a Kashima-coated, Factory-level unit, with an EVOL air spring to increase off-the-top sensitivity.
The Sine suspension soaks up bumps and gives great climbing traction. Mick Kirkman
Alchemy’s build options include the 11-speed, Shimano XT-based spec here, which feels a bit dated compared to the latest equivalent SRAM kit.
A 12-speed GX Eagle bike costs £300 more, although you still won’t escape the iffy bite point of the XT M8000 brakes.
Alchemy Arktos 29 ST first ride impressions
Two things strike you immediately about the Arktos ST: the frame is as solid as an enduro rig, yet it pedals, sprints and climbs exceptionally well.
I love rallying downhills, so alarm bells can ring when I find myself surging uphill with too much urgency and efficiency. Will the payback be a rougher, less planted ride coming back down steeper, beaten-up tracks? Not on the Alchemy.
The Arktos ST is calm, super-smooth and planted, even over really big holes and roots. It feels (cliché alert!) like there’s more travel than advertised and it tracks the terrain sweetly at both ends, generating a ton of grip over wet rocks, roots and edges.
With wheels on the ground, it maintains speed well over staccato hits too.
Smooth pedalling and great climbing. Mick Kirkman
It’s an assured, easy-to-ride all-rounder rather than a razor-sharp reactive slasher, so, despite its shorter wheelbase, it won’t slice-and-dice tight berms and spit you out in as much of a blur as rivals such as Evil’s The Following.
The Sine suspension can also get greedy munching hard landings and compressions. I bottomed-out multiple times riding hard with sag that felt good for grip and cornering support elsewhere (30 per cent).
The rear tyre can ‘slap’ the ground harshly when braking, reconnecting after extending out of the sag position in the air, or landing from smaller drops or steps, too. This is an observation rather than a deal-breaker though, and, overall, it’s a well-refined ride that’s solid, sturdy and planted downhill.
The Arktos ST feels light and fast for climbing and big-mileage rides as well, meaning it would make an awesome do-it-all machine for a ton of UK riders, even if it’s less perfect for warp-speed shredders and slack-geometry fiends who ride every inch of trail like its their last.
Alchemy Arktos 29 ST geometry
Seat angle: 75.5 degrees
Head angle: 66.1 degrees
Chainstay: 43.6cm / 17.17in
Seat tube: 48.3cm / 19.02in
Top tube: 62.7cm / 24.69in
Head tube: 12.5cm / 4.92
Bottom bracket drop: 4.1cm / 1.61in
Bottom bracket height: 33.6cm / 13.23in
Wheelbase: 1,199mm / 47.2in
Stack: 64.2cm / 25.28in
Reach: 45.4cm / 17.91in