Slug CrMo Earthling Review: Otherworldly

Riding shots by Holden Mathis

In my early days in this role, I distinctly remember Miles forwarding me an email from Steven Keyes about Slug’s new website. The typeface, graphics, and photography were unique. It seemed cool and exciting. Phosphorescent photos of banana slugs and hardtails ripping through loamy, urban forests surrounded by hazy, cybersigilistic imagery. It all amounted to an enticing package. In a sea of brand communications, Slug stood out.

For all the excitement of their new branding launch, however, I felt their bikes were ultimately out of my reach. I didn’t have much experience with hardtails at the time, let alone ones made out of titanium. Given my personal remit to focus on more approachable bikes, I stuck a pin in it. The vibe was right, but the vehicle wasn’t. A few years on, the small, San Francisco-based outfit is releasing its first production steel gravel bike. With an array of smaller titanium hardtails and components behind them, the Slug CrMo Earthling is the brand’s first contact with the wider dirt landscape. I spent a short but adventure-filled month and some with their new bike to see what this young brand is bringing to the table and to find out if this is just another run-of-the-mill gravel bike or something else entirely.

Out of the Primordial Ooze

Slug Bikes is run by Steven Keyes, Byron Lee, and Tynan Collins. Each with their own history in the outdoor space, the confluence of their collective talents makes the brand whole. Steven’s time in the industry has defined Slug’s direction, while Byron’s experience as an industrial designer makes their shared vision a more concrete reality. Tynan, a talented graphic designer and artistic lead, has brought Steven and Byron’s work to life through their distinctive branding.

Part of what initially attracted me to Slug Bikes was the declaration that their bikes and components are “proudly made in Taiwan.” Calling it an open secret would be a misrepresentation, but some brands seem to intentionally obfuscate their production partners. Be it a fetishization of homemade products or something less nefarious, the proud and honest announcement that their wares are designed in the US and brought to life in Taiwan struck a cord.

• 
• 

Bikes, especially in this niche, are premium goods. Part of what any brand brings to the table is how it communicates. I think Slug has done a great job at curating a “vibe” around their goods. Following that up by delivering a product that stands on its own merit is essential in creating a legitimate brand, and I was excited to dig into one of their first production offerings, especially one based around greater affordability. Because most of their models have been made of titanium up until now, the Earthling CrMo presented a perfect opportunity to experience the full vibe without a premium price tag.

That said, I had little to no idea what I was getting into when I reached out to Steven Keyes for a test bike. He’d sent over some basic numbers and outlines to get an idea of what size would work best, but I was largely going in blind. I had little more information than the teaser that adorned their website for the past few months.

Slug CrMo Earthling Build Kit

• Frame: Slug CrMo Earthling
• Fork: Frequency Fork
• Crankset: Shimano FC-RX820-1 GRX
• Derailleur: Shimano GRX RD-RX822
• Shifter: Shimano GRX ST-RX820
• Cassette: Shimano CS-M8200-12, 10-51T
• Bottom Bracket: Shimano SM-BBR60
• Front Wheel: DT Swiss G1800
• Rear Wheel: DT Swiss G1800
• Tires: Continental Dubnital 29 x 2.2″
• Headset: Slug Mantle Headset
• Handlebar: Slug Alloy
• Stem: Slug Alloy
• Grips: Slug Tape
• Saddle: WTB Silverado 265
• Seatpost: Slug Alloy
• Seat Clamp: Slug
• Brake Levers: Shimano GRX ST-RX820
• Brake Calipers: Shimano GRX ST-RX820
• Rotors: Shimano RT-CL800

Dressed in the brand’s classic sage green colorway, the CrMo Earthling didn’t seem too alien when it first arrived. A steel frame, carbon fork, and 12 x 100 / 12 x 142 rear spacing were all more than familiar. With clearance for 29 x 2.25 tires, a solid Shimano GRX drivetrain, and a set of Astral Wheels with hubs by White Industries, the Hardwired build kit Slug offers through the CrMo Earthling is entirely fit for purpose. That said, there is a bit more going on under the hood. The Earthling is built with a custom headtube and size-specific, asymmetrical tubing, which felt exceptionally light at first touch. I’ll dig into how it felt in the next section, but I’m confident the work that went into creating this 4130 chromoly tubeset is more than just marketing. It feels premium, and that was discernible right from the start. At $1,850 for a frameset, it’s competitive with a lot of other steel frame, carbon fork models on the market.

• 
• 

• 
• 
• 

The CrMo Earthling also uses fully external cable routing through sleek, simple cable guides on the downtube and driveside chainstays, has internal dropper routing on the seat tube, and extends that fully external design through matching 3D-printed guides on the Frequency Fork. The rest of the build kit performed well, and I was particularly impressed by the Astral Outback wheels and Astral by White Industries hubs. They spin up quickly and dealt with the varied terrain I subjected this bike to really well. The hubs had good engagement, felt strong and responsive, and added good value to the overall package. Although I’ve largely moved on from non-carbon wheelsets whenever possible, this budget-oriented set of Outback wheels would be a go-to any time I want something made of aluminum.

• 
• 

• 
• 

• 
• 

The only element I found disappointing was the Teravail Radia drop bar. At first glance, it appears to be another standard drop bar. However, I found the drops too deep for my liking, the flare lacking in control and width, and the circular shape of the entire profile off-putting. With a longer test period, I would’ve happily swapped these out for something wider or more aggressive, such as the Ritchey Venturemax or Crust Nullabars.

Ride Feel and Geometry

Though I only had about a month with the Slug, I got in a lot of miles. Upon taking it out of the box, I ventured out on a 30-mile loop in Asheville that incorporates several thousand feet of gain, some urban singletrack, and a ripping mixed-terrain descent. From the get-go, the CrMo Earthling felt incredibly light, responsive, and capable. With a 70.5-degree headtube and a raked-out fork, the front end felt far more responsive on singletrack than other fast gravel bikes I’ve tested. Some might imagine that translates to a less-than-ideal feel when things are flat or on a climb, but I think they struck the ideal balance. Bikes such as the Fairlight Secan 3.0 or Surly Midnight Special are still a little more responsive on the road due to a shorter wheelbase and more aggressive overall fit, but the Slug held its own in this regard while also being more comfortable and capable off-road. No matter how hard I leaned or dug into the edges of the tires, the bike kept its line and returned a nice, resonant frequency.

• 
• 

I continued to pedal the Slug on after-work loops, small jaunts on mountain bike trails in Bent Creek, and finally, a massive overnighter with our routes director, Daniel Jesse. I’ll get into how the bike performed with a load a little further down, but unloaded, the Slug handled everything I threw at it exceedingly well. Despite ventures onto chunky rock drops and root systems, I never felt like it was out of place or under-tired. With 435mm chainstays, I still felt the bike was stable enough to keep its line on rough gravel roads where you need to change your line at a moment’s notice. Though the tubes feel light in hand, the bike never reeled or responded poorly to a harsh hit. It’s without a doubt one of the nicest and most capable tubesets I’ve tried this year, and I was stunned by how naturally it took to any challenges.

Slug CrMo Earthling Geo

As I dug further into the numbers, I noticed just how similar the bike is to some of the others I tested last year. The Slug has a bit more comfort built in, with a higher stack number than the Fairlight or Ritchey Septimer, but it feels more capable off-road. With a similar head tube angle, I found that much of the capability I felt was aided by the extra 5mm in fork rake provided by their custom Frequency fork. Designed by Slug from the ground up, the fork features a 415mm axle-to-crown height, integrated cargo mounts on either fork blade, is tested to ISO4210 MTB/XC standard, and can run racks and fenders. With the added rake, it’s one of the best carbon options I’ve tried, and one that pairs well with this already relatively slack gravel bike.

• 
• 

The only element I didn’t get on with was the extra height brought on by surplus axle-to-crown. Unlike several of my other test bikes, I decided against slamming the CrMo Earthling’s stem. Aside from various comments on past reviews remarking on how low my cockpit typically is, I wanted to try something new. The fit out of the box was sufficient, and because I had limited time with the bike, I decided against changing it. Paired with the 74-degree seat tube angle, it wasn’t too far out of the realm of my typical fit. That said, I still felt a little numb in my backside after a few hours in the saddle. Part of that could be down to the saddle, but I believe it’s more so because the distribution of rider weight is skewed toward the rear. It helps make the bike more nimble, but it also puts more pressure on the saddle. Because I prefer a more aggressive fit, this took some getting used to. It’s not necessarily a negative, given the handling benefits it brings, but it’s something to consider if you like to be long, low, and aggressively positioned on the bike.

Attack of the Brain Eaters

I got two overnighters in during my test period. One was a brief trial run to see how the bike fared with a load, and the other was a massive scouting trip on the border of Western North Carolina. In just over 100 miles, the route included almost 14,000 feet of elevation gain, some incredible views, and sweltering mid-summer heat. I’m excited to see what Daniel ends up doing with the miles we covered, but it was an excellent test of this bike’s capacity as a bikepacking rig. Though it may not initially appear to specialize in carrying a load, I found the CrMo Earthling more than capable on the rough stuff.

Most of the terrain we covered was tame and non-technical, but the hours upon hours of climbing and descending on varying forms of chunky gravel gave me a solid impression of what this bike can do while loaded. With well-placed M5 mounts on both the front and rear, I could easily carry a solid amount of gear on my Velo Orange There and Back Rack, combined with some fully packed Restrap Hiplok panniers on the front. With most of the weight on the rear, the bike’s nimble handling was largely unaffected. Climbing the steep gradients on both paved and unpaved roads was just as simple. In the brief moments where we did venture onto some singletrack, the bike was still manageable with a night’s worth of water and gear.

• 
• 
• 

When we arrived at our remote campsite in the wilds of Eastern Tennessee, we settled in and sat by a roaring 40-foot waterfall. Eventually, after eating dinner and chatting about possible routes, we climbed into our tents and went to sleep. Locked deep in slumber from the sheer physical demand of the day, I was jolted awake by an eerie bright light above my tent. Daniel was saying my name.

“Nic, Nic, NIC!”

“What’s up?” I mumbled, half asleep.

“You gotta help me m-,” he stopped mid-sentence and shrieked.

“THERE’S A MOTH IN MY EAR. THERE’S A MOTH IN MY EARRRRR!”

He was thrashing around in pain. I hopped up and tried to make sense of what was happening.

“Here, I have a pair of tweezers; you HAVE TO GET IT OUT!”

At first, I couldn’t quite make out what was happening. I thought something as large as a moth in a small space like an ear canal would be easy to see. But, at first glance, I didn’t see anything.

“Maybe he’s lost his mind.” I thought to myself.

• 
• 

After some looking around, however, I saw a small rice-sized bug fluttering. In the warm dark at two o’clock in the morning, ten miles away from the nearest town, without any cell service, I carefully inserted a very sharp pair of tweezers in Daniel’s ear. He reeled in horror.

“I just don’t want you to puncture my eardrum!” he exclaimed.

“I won’t, I won’t.”

This song and dance went on for a few minutes until Daniel resolved to try something else. I’d tried and tried to get the bug out, but it was just too risky, given the sharpness of the tweezers. After many attempts, he walked down to the pool above the waterfall and tried to drown it. I got back in my tent, feeling guilty and defeated, and listened as Daniel paced back and forth trying to remove the invader from his brain.

In the morning, I woke up, curious to see what had become of my friend. From beyond the pale green hue of my bike, I saw Daniel up and at ‘em. With a wry grin, he told me about how he stayed up trying to wash the bug out, eventually resorting to using his limited store of alcohol fuel to kill it. Doing so had, at the very least, stopped the incessant fluttering, and now he just felt a dead weight inside his ear. Soon, we climbed out of the campsite, pedaled our way to a sleepy little diner in Hot Springs, North Carolina, and enjoyed a hot meal before heading home. Despite my legs needing more rest, the Slug happily plugged up and down the climbs as we made our way through some of the region’s tallest peaks. Unwavering, the CrMo Earthling carried me home.

• 
• 

• 
• 

While I was distracted by the events of that 48-hour getaway, the best thing I could say about this bike is that it disappeared underneath me. Trying so many kinds of bikes can take a toll. Some are less than ideal for the kind of terrain I set out for, and most have some shortcoming in one way or another. While it may seem over the top to suggest this bike has none, it’s hard for me to think of any real detractors. It’s specced properly, rides well, feels premium, looks great, and leaves enough room for the future. The 29 x 2.2” Dubnitals were fantastic, but there was room for more. The cargo and rack mounts aren’t the main part of this bike, but they worked well with a full load. It’s UDH compatible, entirely external, and built around standards most gravel riders probably have one or two extras of. It’s a late entrant to the category, but it seems to have paid close attention to what works and what doesn’t. Whether you’re fighting to get a bug out of your friend’s ear or just out for a ride with a more down-to-earth sense of adventure, it’s nice to have a bike that can do it all.

• Model Tested: Slug CrMo Earthling, M
• Actual Weight: 23.5 pounds (10.6 kilograms)
• Place of Manufacture: Taiwan
• Price: $3,500
• Manufacturer’s Details: Slug Bikes

The Slug CrMo Earthling is now available through Slug Bikes and comes in the Jade color Nic tested, or Iris. Frames start at $1,850, while the pictured Hardwired build kit starts at $3,500.

• 
• 
• 

Further Reading

Make sure to dig into these related articles for more info...