// Arktos 29 Development

When Alchemy introduced the Arktos 29 at the Sea Otter Classic in 2018, it wasn’t much of a surprise. Alchemy had debuted a 27.5-inch wheel version of the Arktos three years earlier, and it seemed natural for a larger-wheel-size version of the bike to exist. But the Arktos 29 was long in the making, overall taking two years from inception to wheels hitting the dirt. For Alchemy, this isn’t the exception. Every Alchemy bike goes through an extensive development process like the Arktos 29.


// US Design and Development

The start of any new suspension mountain bike frame begins with the kinematics, in this case by David Earle, the designer of the Sine Suspension System and a legend in the bike industry. David starts by determining the dynamics of the suspension system, ensuring the bike will climb, descend, and generally handle the way Sine was designed. This process, because of the experience gained on the Arktos 27.5 and Sine, is typically pretty short, taking around a month.

Once David is finished with the kinematics and overall suspension design, he passes it off to Alchemy’s Matt Maczuzak, one of the principals of the company and the person responsible for Alchemy entering into carbon with road bikes 8 years ago.


Matt Maczuzak cuts an Arktos mold using Alchemy’s in-house CNC machine.


Matt works first on the overall aesthetics of the frame, ensuring that visually the frame will match the overall look of Alchemy’s mountain bike lineup. After that, the real work begins. Matt’s long experience with carbon comes in to play as he looks to determine the carbon layup that will maximize strength and stiffness while minimizing any added weight.

Alchemy is unique in that we are one of the few US companies with the capability to design and prototype carbon frames at our facility in Colorado. This enables Alchemy to completely understand the dynamics of a new bike before it goes into full production. Most manufacturers are forced to prototype bikes with aluminum, which only allows them to get a “feel” of a new bike. Aluminum prototypes are typically 30 to 40% heavier than the carbon models, so the ride quality is significantly affected by the weight of the proto itself. Alchemy can also prototype exact replicas to production bikes.


// The Carbon Layup

The carbon used in bicycle frames is called prepreg. Prepreg is the common term for sheets of carbon that have been impregnated with resin. The resin is typically an epoxy with a curing agent so the carbon can be hand placed directly into a mold for curing. The main advantage of prepreg carbon sheets are their ability to be highly engineered, easily handled and the carbon to resin ratio is very consistent (eliminating imperfections at the prebuild level of course results in a more consistent frame). Alchemy buys carbon prepreg sheets directly from Japan and has a CNC cutting machine to create the shapes necessary for use on a frame.

When Matt is looking to optimize the frame layup, what he in reality is doing is determining the layering and orientation of the prepreg fiber sheets. Engineers like Matt can provide almost any desired strength and torsional stiffness by varying the quantity and orientation of the fiber sheets as they are applied in the mold. Carbon is unique in that it is relatively easy to add strength only where needed, while significantly reduce weight elsewhere by proper application of the carbon prepreg. For the Arktos 29, extra material was placed in key areas requiring high strength, such as the head tube and bottom bracket, and both the orientation and layers of prepreg used are proprietary to each Alchemy 29.


Carbon is hand-cut and prepped for application to an Arktos frame.


// The Molds

Alchemy is also unique in that we CNC machine all of our molds in house at our Colorado headquarters. Again, it’s Matt’s expertise that comes into play.

“I’ve been machining the molds for the road bikes for years,” says Maczuzak. “But my first experience with a monocoque design was with the Arktos 27.5 frame. We use a tube to tube construction on the road bikes, so the molds are smaller in comparison because the individual pieces themselves are smaller.”


An Arktos mold waits to be wrapped with carbon.


The Arktos 29 is a monocoque design as well, meaning that the entire front triangle comes out of the mold in one piece. The rear triangle comes out of the mold as two individual pieces that are then joined together in a secondary mold process.

Matt cut the prototype Arktos 29 molds from aerospace grade 6000-series aluminum, starting with the medium size frame for prototyping and ride testing. It took about 30 days from mold-design completion to the point when the first front and rear triangle were pulled from molds. The majority of this time is spent determining the lay up schedule.


// Next Steps

Alchemy has been painting frames at its headquarters in Denver since the start, and like most prototype carbon frames, the first Arktos 29 was painted white. Painting the surface white allows us to easily see any potential cracks in the carbon during our lab and ride testing.

The ride testing period for the Arkos 29 was actually pretty short, mainly because the bike reacted as expected during the lab and ride tests. Alchemy EWS racer Cody Kelley was one of the first people to put any significant time on the frame, and quickly came back impressed.

“It both pedaled and descended super well,” says Kelley. “And the geometry was spot on. I felt super comfortable on the prototype right from the start.”


Cody Kelley waits for the final touches to be applied to his Arktos 29.


// To Production

As anyone who has visited Alchemy in Denver knows, the factory is set up to hand build each bike one at a time. While this process is excellent for tube-to-tube construction, it is far from efficient when making a monocoque frame like the Arktos 29. Building a monocoque frame is more suitably done in batches, as the labor-intensive process requires many fabricators working in unison on each frame. This ensures repeatability and guarantees every Arktos is of the highest quality.


The final product gets built and goes through the paces on one of the harshest testing grounds in the world.


We chose to partner with one of the most distinguished manufacturers in the world, a company that has been working with carbon for over 30 years and is known to produce some of the lightest, strongest carbon frames on the market. But, our development process didn’t just stop with the pass off of the drawings and the layup schedule. We work directly with the factory to ensure that our strict quality standards, as established in Denver, are followed to a “t”. We also continue to quality check throughout the process to see that the frames follow the same procedure with each production run.


Shop Arktos


Now more than ever, cyclists are venturing off paved roads and exploring other riding styles, leading to a desire for more versatile bikes with more tire clearance. With the rapid development of new bikes and technology, the industry is becoming increasingly complex. To make things easier, we recently broke our product line into three categories: Road, All-Road, and Gravel. We are here to explain the differences in the categories, what they are designed for, and which one (or two, or three) might be right for you.



The road category is the most familiar of the three. If you are thinking about getting into a local cycling club or want to take a shot at racing, this is probably the category for you. Road bikes are designed to be efficient, light, responsive, and corner hard. Not all road bikes are created equal and the Atlas is a defining example.

When we designed the Atlas we incorporated years of cycling experience in Texas and Colorado to produce a road bike that will perform on every type of ride. Whether you are hammering corners on long mountain descents or grinding through that last crit lap, the Atlas has you covered. The Atlas was specifically designed to maneuver the city streets and cruise the country roads. The unique carbon layup and tube construction gives the Atlas unparalleled compliance while maintaining stiffness, so you can stay comfortable in the saddle and stay fast out of it. The Atlas offers 30mm tire clearance and is dual-routed to allow for internal eTap, Di2, or mechanical routing. If you’re main focus is sticking to dry paved roads, then the Atlas is for you.




Born out of want for a road frame with more versatility, All-Road has recently evolved into a segment of its own. These bikes are perfect for the commuter and weekend warrior or the rider looking for a “quiver-killer”. If you like taking new routes and don’t mind some packed dirt then this is the bike for you.  We saw a need for a road bike that can take a punch, thus the Hyas was born.

Our Hyas features its own front and rear triangles with unique tube shapes to give you more compliance than the Atlas without sacrificing stiffness. We left room for 700c x 40mm tires, but kept a short wheelbase for tight cornering on paved roads. When road conditions change fast, you need a bike that will adapt. The All-Road line gives you unprecedented comfort without sacrificing control.




If you’re unaware of the latest gravel trend in the cycling industry, you’re probably living under a rock (which would actually make a gravel bike a very practical option for you). So what does this mean? At a 10,000 foot view, huge tire clearance and enough bottle cage and rack bosses to trek the Sahara. Most companies are achieving this by throwing as many things as they can at the bike and dropping chainstays to accommodate tires larger than anybody would practically need for a gravel bike. However, all of these measures, as with a lot of things in the bike industry, are attempts at offering something visual that ends up sacrificing ride quality, a measure that is in our brand identity to NEVER sacrifice. Form follows function, not fashion. 

When we set out to offer an answer to this undeniable market segment, we wanted to take our time and be much more intentional in our design. We wanted to think critically about what was necessary for races as gritty and challenging as the Dirty Kanza without sacrificing the ride quality that Alchemy is known for. Our answer is our new Ronin line. On the carbon side, it comes in the form of a bike offering comfortable  700/45mm tire clearance, triple bottle cage mounts, fender mounts for the utilitarian riders out there, bento box bosses, and a custom ride-tuned carbon layup in a sub-17lb (58cm with Ultegra build), category leading superbike that, for kicks, is the ONLY fully-customizable geometry bike in the gravel category.

The geometry and tube profiles on these bikes are optimized to ride everything from rural b-roads to local singletrack. While it can comfortably handle a local group ride with 28mm tires, that’s not necessarily why we built it. This line is purpose-built to get dirty while gobbling up rough roads and trails. Looking for something to use as a “quiver-killer” to handle everything from road racing to commuting and your local gravel ride? We’ll point you towards our All-Road bikes. These bikes are intentionally designed to kick more ass on gravel than anything out there.


// Why Short Travel?

With the introduction of the new Arktos 29ST (for short travel), Alchemy now offers two different 29er options to the market. Both bikes feature Alchemy’s patented Sine Suspension, a system which maximizes pedaling efficiency without detracting from downhill performance. So why choose one over the other? Well, the answer really depends on the type of riding you are doing. Here is a breakdown on short travel versus long travel and what makes the Arktos 29ST the next greatest trail weapon.

// Sine Performance

The heart of the Arktos 29ST is the Sine suspension system. The beauty of the Arktos is how it pedals and descends and that’s because of Sine. Sine is regressive through the first part of the travel to absorb small bumps and provide climbing traction, progression in the middle of the stroke to avoid wallowing on big hits or in hard, fast corners, and then slight regression again at end stroke to enable full use of your travel.

// Arktos 29ST

The Arktos 29ST is trail bike at heart, with 120mm rear travel and 140mm fork travel. It fits in the category with the Yeti SB130, Transition Smuggler and the Santa Cruz Hightower. We spec a Fox 36 fork, which gives you an indication of the terrain we expect the bike to be used in: rough and technical. The Arktos 29ST has modern trail bike geometry with a 66.1 head angle with 75.5 degree seat tube angle. While the Arktos 29 was designed to crush fast, open, super techy EWS tracks, the Arktos 29ST is capable of hitting the same bone-tingling descents, but adds a little fun in the mix. It turns quicker and changes directions faster on those tight switchbacks and still has that slack geometry to keep it stable at speeds. 


So, in the end the main difference to choose the Arktos 29ST over the standard Arktos 29 is really in the terrain you plan on riding, and how you plan on riding it. Is the terrain tighter and technical, with the focus on going fast AND having fun? Well, the more flickable Arktos 29ST is the bike for you. Are you hitting faster, most open terrain and wanting to be the first of your buddies to the bottom? In this case, the Arktos 29 is the bike of the day for you.

The 29ST is quicker in turns and more reactive to transitions where the Arktos 29 is more stable at high speeds. It makes sense, right? The ST has a steeper head angle and a shorter wheelbase, which are the important factors when getting a bike wedged around tight turns. Both bikes, by the way, feature 44mm offset forks and steep enough seat angles to put you in the perfect position over the bike for climbing. Now that you know the difference, the choice is yours.



// Designed for Perfection

If you’ve read about Alchemy’s mountain lineup, you likely know that the key to an Arktos is the Sine suspension system. Sine is interesting because it allows for a varied ratio of compression force from the rear wheel to the rear shock as the suspension moves through its travel. Technically, we talk about it in these terms: regression at the start of the travel in order to allow the Arktos to absorb small bumps and provide climbing traction, progression in middle of the shock stroke to get the bike into the meat of the travel, and regression again at the end to allow the bike to hit its full travel. 

But, let’s break that down into layman’s terms and then relate it to how an air rear shock functions to better understand the benefits. For starters, the main result of the Sine link is that it allows the rear wheel to move more easily through its travel at the start, harder in the middle, and again easily at the end of the travel. Well, you might be asking yourself, “Why would I want that?”

The answer is actually pretty simple, at least once you understand the fundamentals of an air shock design. Air shocks use air as the main spring component to support the rider on the bike. Because air is a small molecule and air shocks reach high pressures at bottom out (at least 5 times the starting static pressure) shock manufacturers have to utilize tight tolerance air seals or the air would leak out of the shock. That’s a good thing for sure, as no one wants to be stuck out on the trail with a leaking, bottomed rear shock. The downside of all of the sealing is friction. Air shocks, by nature, have more friction than coil shocks because of the seals required to keep the air in. And the most noticeable place that the friction is felt is the start of the travel. One way to overcome that friction is a design (like Sine) which increases the rear wheel to rear shock ratio at the start of the travel. With such a design, the rear wheel can move through small chatter without you feeling it and the wheel keeps locked to the ground so you aren’t getting tire spin.

Okay, so that all sound logical, right? Well, it is, but the problem with air shocks is that they are very linear through the middle of travel. That means, once you are past the point of initial friction, the shock quickly wants to keep that force moving to the very end of its travel, where all of those small molecules are highly compressed and can finally resist the forces coming from the rear wheel. Well, that’s where the varied nature of Sine comes into play. The Sine link physically changes direction after initial wheel movement, and the ratio of wheel to shock travel is reduced, increasing the force required to compress the shock. This IS what makes Sine so great, as it actually counteracts the air shocks linear nature and allows the suspension to stay high in its travel. Simply put, when you hit a bump, there is still some shock travel left to allow the bump to be absorbed.

So, we are through the first two parts of the travel, where we have the wheel moving easily at the start of it’s travel and the middle is effectively absorbing bumps. Now you are probably wondering what happens when you hit a big drop or bump, the kind that immediately sends the suspension to the end of the travel. As mentioned before, air shocks become very firm at the bottom of the travel, as the shock becomes fully compressed and the air no longer has space to displace. If you’ve ever experienced getting to bottom abruptly, you know it’s hard on both your bike and your body. Again, this is where Sine comes to your aid. As the Sine link physically moves back in the opposite direction, the leverage ratio on the shock actually reduces, requiring less force from the rear wheel to make the shock activate. The Sine link is counteracting the progressive nature of the shock (by making the suspension easier to get into the last part of the travel). It’s a yin and yang thing, but the result is that you get all of your suspension travel with an almost bottomless feel.


Okay, so you’ve just heard what sounds like more marketing-speak: “You are getting the best of both worlds”. The difference is that once you understand the basic design of Sine AND how it works in combination with an air shock, you can see that it’s POSSIBLE to achieve the best of both worlds. And as a result, you begin to understand how an Arktos can pedal well, absorb small bumps, provide excellent suspension throughout its travel.


There’s no “set in stone” method for fitting a bike to the rider, but generally speaking, knowing a few benchmark measurements will help to ensure you’re comfortable and ready to roll on your new bike. Below are five Alchemy tips to consider for the perfect bike fit:

1. Make sure you have the correct frame size. If you don’t have the right frame from the beginning, you’ll find it nearly impossible to get comfortable no matter what adjustments you make later. To figure out the right size for you, a few basic measurements are necessary:

  • Your leg inseam (from your saddle to your foot)
  • Your torso length (from your saddle to your sternum)
  • Your arm length (from the end of your collarbone to the middle of your closed fist)

From there, enlisting the help of professionals like Alchemy can help even further. We can run a few measurement equations once we have the information listed above and ensure you’re selecting the perfect size.

2. Fit your bike for how you currently ride. An important rule of the road: do what’s best for you. You may aspire to match a riding partner or pro that you follow, but it’s important to set your bike up to match your current tendencies and abilities. Basically, the better the fit, the longer you’ll ride the bike.

3. Make easy adjustments to existing components: Seems like a no-brainer, but remember to make obvious adjustments with the bike’s existing components, including the seat height, seat angle, and fore-and-aft seat position. The saddle height is important because, if not adjusted properly, it can add constant stress on the legs and knees. Another critical adjustment you can make is handlebar reach, which is the distance you reach from your saddle to your handlebars. Too-long of a reach can mess with your weight distribution across the front and back wheels of your bike, which ultimately means you’ll be uncomfortable and not have good control of your bike. Too-short of a reach can position you too upright, ultimately decreasing your power.

4. Consider getting fit by someone certified in the Retül Fit System: We may be biased since we’ve been certified in the Retül Fit System for a decade, but Retül Fit is undoubtedly one of the most comprehensive bike fitting processes in the industry. Refined into a repeatable step-by-step methodology, certified fitters, like some of us at Alchemy, can customize riders’ bikes and equipment to keep them riding longer, faster, and with more comfort. Starting with a pre-fit physical assessment, your fitter will consider your body’s limitations, any previous injuries and pains, and your overall goal for the bike. From there, the process turns to their Vantage Motion Capture System to collect real-time, three-dimensional data from your pedal stroke. The data is then compiled into a system so we dial you into the perfect ride position.

5. Check your cleat fit: Though not necessarily in line with the basic bike fit, the placement of cleats on your bike shoes can also impact fit. Set too far forward, they can cause knee pain, Achilles discomfort, numbness, or hotspots. Too far back and you won’t be getting the optimal power transfer from your muscles to the bike. There are various ways to do this, but this is a place where professional fit advice may be worth it to help avoid injury.

At the end of the day, the importance of fitting a bike comes down to taking active measures to decrease the chance of physical damage to you as the rider. Take the cautionary time to cross all your “T’s” and dot all your “I’s” when it comes to the fitting, and see a professional fitter so that you’re ultimately not inflicting any extra (and unnecessary) harm to your body, or to the bike you want to enjoy for years to come.

With one of the biggest crowds in its history (74,000 total in attendance), the 2018 Sea Otter Classic made for one hell of a show this year. In its typical patriotic-centered fashion, the Monterey, California Dual Slalom course was lined from top to bottom with throngs of American flags, animated spectators, and even some cheering animals (like a pig with a flag in its mouth one day.)

Inside the fence, Cody Kelley and Anneke Beerten were running the courses in both the dual slalom and downhill races. Cody came in 9th place in the downhill event, but struggled with a fall during the dual slalom. That didn’t stop him from getting right back up and entertaining the crowd with one of his signature whips, giving the crowd something to cheer for. Anneke came in 2nd place in both events, making us proud as she pumped, jumped and slid down the courses. When they weren’t on the track, Anneke and Cody were getting plenty of attention from their fans at the Alchemy booth. All-in-all a successful weekend for the racers, but we were also pumped to show off the newest addition to the Alchemy family.

At this year’s Sea Otter Classic, we rolled out our new (and long-awaited) Arktos 29 mountain bike.

The Arktos 29 is the ultimate do-it-all trail weapon. With the new 29-inch full suspension option, we’ve added a Super Boost rear triangle (157-milimeter, wider flanged rear hub) and increased reach to this new model. The heart of the Arktos is the Sine Suspension System, our patented design that’s plush at the start of the travel, progressive in the middle, and smooth at bottom out.

To celebrate the introduction of the bike, we showcased two new color options (vanilla and grey) at our booth and arranged a little surprise for Anneke and Cody. We designed custom 29ers for them, each with a one-of-a-kind paint job. Cody’s bike is full-on ‘Merica with red, white, and blue stars and stripes, while Anneke’s bright orange bike with the Order of the Lion pays homage to her Dutch roots.

With an overall successful launch and prominent presence at Sea Otter, we’ve already picked up some note-worthy press about the Arktos 29 debut, including BIKE Magazine, Pink Bike, and Bike Rumor.

Want to get your hands on one? They’re available for order today.

When it comes to mountain biking, there’s no denying the fact that your bike’s suspension determines your ride quality. So, when designing the Arktos, our latest mountain bike, we enlisted the expertise of renowned suspension designer David Earle, who has now given us an unparalleled mountain bike suspension system: Sine Suspension. So, what is it?

The Sine Suspension system is a one-of-a-kind dual short-link system, derived from superior design elements of David’s previous coveted suspension systems. What makes this one so different (and ultimately even better) is that it didn’t start with engineering, but rather with a focus on suspension kinematics. Focusing on the bike’s movement and design has allowed David to create an ideal mountain bike suspension system that can perform on all types of terrain.

Travel with the Sine Suspension system looks like this:

  • Beginning of stroke: regression to absorb small bumps and provide climbing traction
  • Middle of stroke: progression to avoid wallowing on big hits or in hard & fast corners
  • End of stroke: more slight regression to enable full use of rear wheel travel

This pattern is designed to minimize chainstay growth, improving pedaling efficiency and keeping the suspension active under braking.


The Sine Suspension system is optimized at 30% overall sag.

Sag is the amount of travel the shock compresses under normal rider weight. We recommend that you set the sag to 30%, but personal preference and riding conditions are also factors influencing the amount of sag desired.

To check sag:

  1. Gear up so you start with an accurate rider weight.
  2. With someone holding the bike, stand on the pedals and get in your normal riding position on the bike.
  3. Bounce up and down on the bike, compressing the rear end of the bike and the shock; when you are steady again, have someone push the travel ring up the shock against the wiper seal.
  4. Dismount the bike gently (so you don’t move the travel ring).
  5. The amount of stanchion shown between the wiper and travel ring is your sag. 30% sag would show 21mm of exposed stanchion between the wiper and travel ring.

An ideal suspension sag will optimize the three areas of travel: negative, mid-range, and deep travel. You’ll know you’ve perfected the sag when you experience a plush, small bump feeling in your negative travel, a firm and lively mid-range travel, and a ramping and bottomless end travel. Still not sure if you’ve set it up properly? You can contact us and even visit our Denver factory where we can help you find the perfect settings.