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Build the Custom Mountain Bike of Your Dreams This Year

Sometimes, I think Alchemy is one of the most unconventional bike companies out there. Sure, we make bikes and then we ship them, which isn’t out of the ordinary. But we oftentimes follow a rather circuitous route from point A to point B. We’re well known for custom manufacturing bicycles in Denver, Colorado on the road side. This has carved a nice niche for us —custom is our game. But we’ve also expanded our custom made bicycles program to include mountain bikes. And for many riders, we’re building bikes to their exacting specifications. Such is the case with anArktos 29 ST we recently built for one of our customers. Below we’ll take a deep dive into the method behind this specific bike so you can see everything that goes into the Alchemy custom mountain bike process.


For starters, the worst-kept secret in the world is that anArktos 29 can be converted to an Arktos 29 ST, and vice-versa. The front and rear triangles are the same, so all it takes is a link, the correct travel rear shock, and an air rod (to travel adjust the fork) to go between the two models. This compatibility is super advantageous for our customers. It provides a wider range of colors to choose from and — for a relatively small cost — you can toggle between two different categories of trail bikes: 160 front/140 rear on an Arktos 29 (if you’re getting rowdy), and 140 front/120 rear if you’re just interested in general trail bike riding. The custom bike we recently built was an Arktos 29 ST, but we started with the vanilla-colored frame from the standard Arktos.


Upgrade to a Fox X2 for a greater level of adjustability.
The first thing we did with this bike was upgrade to a Fox Float X2 shock. X2’s only fit on large and XL size frames. The reason to upgrade is because of the greater level of adjustability (versus a Fox DPX2 setup). The compression and rebound adjustment range is quite large, allowing riders to run a relatively light or firm set up, depending on your preference. We tuned the shock at 6 clicks in from full open on low speed, and 2 clicks from full open on high speed, with 25% being our baseline sag.
The 150mm Fox 36 Grip 2 fork.


On this particular mountain bike build, the client was intending to ride some fairly aggressive terrain. We decided to start with a 150mm Fox 36 Grip 2 fork. This might sound like a bit of an imbalance (because the ST rear travel is only 120), butas the reviews have noted, the ST is a very capable bike, and the rear travel feels like more than the numbers suggest. The client weighed 195 pounds, so we set up the fork pressure at 80psi with 3 air volume tokens. We ran the rebound at 4 clicks in from full out on high speed, and 2 clicks in from full out on low speed rebound. Compression settings are 4 clicks in from full out on low speed, and full out on high speed. This provided a relatively light set up to match the feel of the rear end.
We love ENVE M630 wheels: strong, durable and light for a trail wheel.


It’s true: We’re partial to ENVE M630 wheels. Luckily, this customer was, too. Why M630? The 6-series wheels have a little more give versus the 7-series wheels, feeling more like an aluminum rim than a typical harsh carbon rim. Also, unless you’re riding really rocky terrain, the rim strip that the 7-series wheels use is a little overkill. We opted for the 30mm width 6-series too — not anything wider. More on this choice below.
Believe the hype. The Maxxis Assegai is one of the best all-around tires made.


A 2.5 Maxxis Aggressor out back and 2.5 Assegai up front…this might be the most versatile tire combination out there. It’s good in almost every condition, and since both tires are extra durable, you aren’t buying tires every few weeks. We mounted a DD Aggressor tire in the back, but maybe not for the reason most would think. The DD tires — while certainly providing additional pinch flat protection — increase sidewall support. If you’re running pressures in the low 20s, you’re going to need it. Regarding the rim and tire combination, running M630s seems to give these two tires the perfect profile. Anything narrower and the tires are too round, so you can’t get out to the side knobs. Anything wider and the tire is too flat, so you’re falling off the side knobs.


We outfitted this bike with a Shimano XT 12 speed drivetrain, 32-tooth chainring on 170mm cranks with an 10-45 cassette. Why this cassette versus the wider 51 tooth version? For starters, the 10-45 provides enough gear range for most riding. Second, you’ll appreciate the smaller spacing between gears versus the bigger range cassettes. While this rider was taller, 170mm cranks were an obvious choice. The terrain the customer rides daily required pedaling through rocks. That little bit of extra space…well, it gives him a little bit of extra space.


We outfitted this bike with a Oneup 160mm travel post. To be honest, it’s not our favorite post: that would be the budget friendly X-Fusion Manic. But the 170mm Manic was too long for this rider, so he wouldn’t be able get the saddle low enough at full extension. The 150mm Manic was an option, but the client wanted to get the most drop possible.
Finally, someone made a great grip: the DMR Deathgrip.


We outfitted this bike with DMR Death Grip thick grips with no flange. If you have big hands, this is the grip for you. It has waffle underneath, and quite a bit of padding on top. The padding doesn’t move around much (despite how soft it feels), and it helps take out any sharp harshness you would normally feel transmitted from the trail to the bar.

Handlebar and Stem

ENVE M6: Laterally stiff but vertically compliant, perhaps the perfect bar.
Another accessory we swear by is the ENVE M6 handlebars. That might seem kind of crazy, as we haven’t traditionally been big fans of carbon bars — most are too stiff and have almost zero feel. The M6 is something different. It has vertical compliance and lateral stiffness, in a perfect combination. We cut the bar to 760 which, with the grips installed, delivered a 770 overall length. That may seem a little narrow, but keep in mind that all the fast Enduro World Series guys ride 760 or narrower (Ritchey Rude runs 750mm wide bars!) We outfitted the bike with a 55mm M6 stem because we love how well ENVE designed the stem to go with the bar (the clamping is nice and evenly distributed).
Oh, those brakes! Shimano XT 4 pots are really as good as it gets.


The new XT 4-pots are truly a step above. They’re strong, consistent, easy-to-maintain, and for most terrain, provide plenty of power with 180mm rotors front and rear. The new brake pads in the 4 pots have also been redesigned to eliminate any potential for rattle of the pad in the caliper. The fins are smaller, and the pad edge has been extended to fit tightly into the caliper.


Most riders are really particular about their saddle. This client was no exception, but he choose a rather standard saddle: a WTB Volt, the narrower version, 135mm.

Ready to Build Your Dream Mountain Bike?

If you’re interested in talking about bike details or want Alchemy to build something special for you, contact me and we can talk shop. We’re looking forward to making your dream custom mountain bike a reality. Contact us to learn more about our custom mountain bikes >

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