Bearclaw Thunderhawk Review: Titanium Dream Machine

The Bearclaw Thunderhawk is a performance-minded 650B gravel plus bike that’s equipped to handle road, trail, and everything in between. Miles got his hands on this category-bending machine to see how much the Force 1 27.5” MTB build could handle. Here’s our review after a few months of riding gravel roads and singletrack, and a first place finish on a new bikepacking event in southern California.

There’s a small part of me that has always been slightly skeptical that titanium bikes are worth their invariably higher price. But, there’s a larger part of me – one that may ring true for many of our readers – that really wanted to some spend some quality time on a well-made titanium bike to see what all the hype is about. A titanium frame starts to make a lot of sense when it comes to bikepacking, considering its fantastic strength-to-weight ratio, corrosion resistance, responsiveness, minimal weight, and an enigmatic mix of compliance and stiffness. I can also see huge benefits for riding this type of bike for endurance athletes in the bikepacking world. Even though I’ve never had any durability issues while bikepacking with carbon bikes, I’d be more inclined to ride a titanium bike out into the unknown.

Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Highlights
  • Angles: 71.5° Headtube, 72.3° Seattube
  • Chainstay: 428mm
  • Bottom Bracket: SRAM PF30
  • Hub specs: 12 x 100mm (front); 12 x 142mm (rear)
  • Seatpost Diameter: 31.6mm
  • Max Tire Size: 650B X 2.4″ / 29 X 1.8″
  • Weight: 20.62 POUNDS (9.35 kg)

The Bearclaw Thunderhawk, a relatively new offering in the bike world, caught my attention immediately. Before long, I was chatting with Jason, the owner of Bearclaw Bicycle Co., about the different build options available, where I would be riding, and what I wanted to get out of the Thunderhawk. It was obvious that Jason had a particular attention to detail that pairs well with the high-end titanium bikes he’s selling, and we ended up building a bike up that very closely resembles the Force 1 27.5” MTB model from their website. For the last few months, I’ve taken the Thunderhawk out on many extended day rides that included everything from tarmac to technical singletrack, as well as a 300-mile self-supported race at the Julian Bikepack Challenge in California. For those interested in what a bike like this can handle, and what it can’t, I’m pretty confident I’ve been there…more than once.

Bearclaw Thunderhawk Review

Bearclaw Bicycle Co.

Before we get into the nitty gritty, a little rundown on Bearclaw Bicycle Co. and its owner, Jason Lowetz. A bike called the Bearclaw Thunderhawk deserves some explaining. I reached out to Jason with a few questions about the company, the bike, and the unique carbon fork that was designed specifically for the Thunderhawk.

What’s the story behind Bearclaw Bicycle Co.?

In the summer of 2011, I opened Einstein Cycles in Traverse City, MI. We didn’t want to sell Tony Little Gazelles and Abdominizers to stay in business through our brutal Michigan winters. Fat bikes were just coming out and we ordered in a few Surly Moonlanders and Pugsleys. We knew this sport would be taking off, so we immediately got to work on creating a small network of winter trails to be groomed and maintained by volunteers, myself included. Fast forward to 2013 and we had several miles of trail, a snowmobile groomer, and were selling out of fat bikes. I had an idea for a fat bike frameset with a cross country MTB geometry, no front derailleur mount, and a sleeker look. I dove head first into the world of bicycle frame and fork production.

In 2015, we were selling our Balthazar fat bike frames and Blitzen forks. About that time I started getting into ultra-endurance gravel rides and bikepacking, so I began designing an all-road/gravel bike. I wanted it to be light, fast, durable, and to have clearance for wide tires. This is when titanium entered Bearclaw’s life. There is no better frame material for bikepacking in my opinion. After several prototypes and modifications to my original design, THUNDERHAWK was born. Not long after THUNDERHAWK we introduced BEOWULF, our B+ XC bike. We then created a Ti version of Balthazar called FRANK. We will have two more bicycles available early 2019: BEAUX JAXON, a B+ drop bar bike, and BUCK MACHO, a trail shredpacking stallion.

Bearclaw Thunderhawk Review
Photo by McCullen Murphy

Tell us a little bit more about you. What’s your story?

I was born and raised in Michigan and always had a passion for the outdoors. I went from snowmobiling and dirt biking as a teenager to cyclocross and criterium racing in Southern California in my early 20s. I was making a solid living working at a bike shop and selling microphone stands on eBay when I reconnected with a former flame and moved back to Michigan. Baby #1 was on the way pretty much immediately, and though I had a garage chock full of mic stands that I hauled cross country in a 22-foot Budget truck, I knew I was destined for more. That said, I opened up a garage bike shop. We dry-walled, painted, and bought a cash register. We put our sign out in the front yard and later that day we got shut down by the township. The next day I had myself a retail space about a mile from our house, and Einstein Cycles was born. My wife and I just celebrated our seven-year anniversary by not celebrating, and we are smitten with our two kids. Life is good!

Thunderhawk, Beowulf, Balthazar, and Frank… how on earth do you come up with these names?

One of these days the Chet Bearclaw story will surface and I’m sure a blockbuster movie will be made. Until then, it’s impossible to explain anything, really.

What makes the Thunderhawk so special for Bearclaw?

THUNDERHAWK is the ultimate shred-venture, bikepacking bicycle, with looks that could kill. It’s proven to be the answer for people who want a drop bar bike capable of exiting the pavement and riding in the grass, dirt, rocks, sand, and mud. With its big tire clearance, endurance road geometry, lightweight yet durable Ti frame, 650b or 700c wheel option, and multiple cage/rack mounts, it’s the best thing to happen to people since the 1969 Arctic Cat Panther.

Tell as a bit more about the Thunderhawk’s new fork.

Nobody was making a gravel fork that had the tire clearance, double triple cage mounts, durability, and look we were after. We designed RAMHORN based off our Blitzen fat fork. It has the same blue steel look. It’s also big and strong. We designed it to be 35% stronger than test standards require. Most importantly, it maintains a 405mm axle to crown while clearing 27.5×2.8” & 29×2.4” tires. It also has plenty of clearance for low knob 27.5×3” and 29×2.6” tires.

Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review

You recently announced the production of new chainrings as well. Are we going to continue to see more products being produced by Bearclaw?

Yes! There is much room for creation in the bicycle industry. We are currently working on our own chainrings for our new BEAUX JAXON B+ gravel bike. BEAUX is boost spaced, which limits us as far as front chainrings. We are developing properly boost-spaced 42, 44, and 46T rings for going fast aboard BEAUX JAXON.

What’s next?

We just acquired a new space in Elk Rapids, MI, which will serve as our HQ.
We are about to launch our new website and web store.
We will be bringing a few ambassador riders on board for 2019.
We host the Sancho 200, a 200 mile gravel rice (race/ride), June 8th, 2019.

What is The Thunderhawk?

As Bearclaw puts it, the Thunderhawk is “a performance-minded 650b road plus bike that’s equipped to handle all-road adventures, mixed-terrain endurance races, gravel grinders, and long bikepacking trips.” The double-butted titanium frame has clearance for up to 700 x 46 (29 x 1.8”) or 650 x 60c (27.5 x 2.4”) tires, opening up a wide array of potential terrain and maximizing the bike’s overall versatility. In a nutshell, they were able to achieve this clearance thanks to the strength of titanium. Namely, a narrow billet Titanium chainstay plate which also allowed them to close the gap slightly between the chainring and stay. With that said, the Thunderhawk’s geometry doesn’t stray too far from other gravel bikes we’ve seen, including the Norco Search XR I reviewed last year, and might not be considered (geometrically) as a drop-bar mountain bike like the Salsa Cutthroat or Fargo. The Thunderhawk really is a performance-minded gravel bike that happens to work well with fairly large 27.5” mountain bike tires.

Bearclaw keeps up with bikepacking trends by including rack and fender mounts, three bottle cage mounts, and 12mm thru-axles. The externally routed cables, although maybe not as slick as internally routed ones, are easy to install and maintain, which is a definite plus for both endurance racing and bikepacking. As Jason touched on in the Q&A above, a custom carbon fork provides all the clearance you could ever need, along with triple cage mounts and fender mounts. Currently, the Thunderhawk is offered in four different builds, that can be built up around either Force 1 or Rival 1 drivetrains: 650B Road+, 700 CX/Gravel, 700c Road, and 27.5” MTB. After some deliberation with Jason, we decided to go with Schwalbe Thunder Burts (27.5×2.25”) on Industry Nine UltraLite 235 rims and Torch hubs. Just like the frame, the wheelset is lightweight, stiff, reliable, and provides a noticeably quick engagement that is well suited to tackling technical terrain on a drop-bar bike. Other than that, the Force 1 Thunderhawk I’ve been riding is almost identical to the build details on the Bearclaw website, which I’ll elaborate on below.

  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review

Mountain Biking on a Gravel Bike

Upon receiving the Thunderhawk, like with most of the bikes I review, I started off pretty slow and built up from there – maybe some light paved riding to get a feel for the bike, make adjustments, ride some dirt, go on a quick bikepacking trip. Even considering the aggressive nature of the bike, it didn’t take long for me to end up on some Colorado singletrack that begged for some help from front suspension and larger tires. However, this was also my first realization that the Thunderhawk could handle a bit more chunk and techy trail than I had first imagined. Unloaded, the stiff titanium frame and purpose-driven components allowed me to successfully navigate a wide range of terrain that was more suitable for a hardtail mountain bike.

Looks of confusion, a couple thumbs ups, and a young boy who turned to his father and said “Dad, that’s not a mountain bike,” really sums up my time with the Thunderhawk. It’s technically not a mountain bike, and it definitely doesn’t look like one, but it sure as hell will bring you to places where you might just wish you had one. I can see the appeal of owning one high-end bicycle, and swapping wheels (and perhaps stems) to make one extremely versatile bike. Will a bike like this replace a true hardtail mountain bike? No way. But the Thunderhawk can definitely hold its own on terrain you wouldn’t expect to see drop bars and gravel-bike geometry.

Soon after riding more rowdy terrain, I was quick to swap out the stock SRAM 42T chainring for a Wolftooth CAMO System and 32T ring, which paired well with the 10-42 cassette to give me a fighting chance on steep singletrack climbs. Normally, I’d also have swapped out the 100mm stem for something shorter, but this time I figured I’d keep everything set up as is, and see if I could get used to riding in a slightly more aggressive position than I was used to.

  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review

Thunderhawk vs. Julian Bikepack Challenge

The Bearclaw Thunderhawk will likely be of particular interest to endurance riders and those looking to get into some self-supported style events in the future. Routes following gravel roads, with some easier singletrack mixed in, would be totally appropriate for this bike. Plus, the mix of high-end components that all scream fast and light are appealing from a race standpoint. For the sake of science, I opted for my most minimalist packlist ever for my attempt at the Julian Bikepack Challenges BFL this fall. I approached the race, at least from a bike and gear perspective, with the idea that the only real way to appreciate a lightweight, performance-minded bike, is to maintain exactly that.

I left behind my shelter, pillow, inflatable sleeping pad, cookset, and clothing I could live without, resulting in an incredibly lightweight final setup. I focused on keeping the front end of the bike unweighted, knowing that as I grew tired I would be struggling to navigate technical terrain. The bike handled great. Actually, better than expected, especially with my ultralight setup. A good portion of the Julian Bikepack Challenge calls for a hardtail mountain bike and big tires, as there’s a heavy dose of soft sand and extremely chunky descents in the mountain and desert regions of the route.

  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review

During climbs, I was impressed with the bike’s overall stability and speed, poking my way through several technical climbs that wouldn’t have been much easier with bigger tires and flat bars. It was a different story on the chunky descents that were littered across the route, most of which had me wishing I had a mountain bike with front suspension. I found things to be pretty harsh on my hands on the longer hills, and I found the 130mm drops on the Thomson Alloy Dirt Drop bars a bit too aggressive of a position for technical riding. I was hurting while riding in the hoods, and frightened while in the drops. I’d be inclined to choose carbon bars like the Salsa Woodchipper or Cowchippers, which are both available in carbon models and 46cm widths.


I was especially impressed with the Industry Nine wheels and Thunder Burt tires, as they took the brunt of the rough trails I encountered. They came setup tubeless straight from Bearclaw, and after adding a little extra sealant before the race, they required no maintenance during or after the event. There were more than a few occasions when I was slightly worried about the durability of the Thunder Burts’ sidewalls, but they held up to some major abuse just fine. The same can be said for the Industry Nine UltraLite 235 rims and Torch hubs, which are incredibly stiff, lightweight, and proved durable on my watch. The UltraLite 235’s have a claimed weight 1,320g for the set, which isn’t far off from their carbon offerings. The internal width of 23.5mm mixes well with the 2.25” tires, and 24 straight-pull spokes mean the interface between hub and spoke is solid. Industry Nine recommends a tire width from 33-55mm (1.3”-2.1”). These are the same wheels that Jay Petervary won the inaugural Silk Road Mountain Race on this year, and in our Q&A with Jay he was quick to say that “turning over a lighter wheel mass is significantly easier” when compared to plus-sized alternatives, and I have to agree. .

The lightweight nature of the entire build meant quick acceleration on hard-packed surfaces, even with 27.5 x 2.25” tires. Plus, a fairly standard gravel bike geometry – somewhere in between a race-specific drop-bar bike and and a longer wheelbase touring bike – meant I was comfortable on the majority of terrain I encountered.

  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review


Intrigued by his presentation on outdoor gear textiles at the Bikepacking Summit last September, I got to talking with Greg Hardy from Rockgeist about a custom frame bag. Titanium bikes deserve special bags, so that’s exactly what the Thunderhawk got. Soon after sending in the necessary photos for Rockgeist’s Photofit custom framebag process, I received a 2.92 Cuben Fiber half framebag, complete with Rockgeist’s new “black sparkle” Fiber Flight Zipper. Clearly, the proverb “you can’t have your cake and eat it too” is false. To keep things consistent, I also ran a Honeypot Feedbag alongside the new Spacelink stem bag anchor.

  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review

The whole kit paired well with the Thunderhawk’s demeanor. Space metal and space fabrics look great together, not the mention the high quality finish that we’ve come to expect from Rockgeist. The new black sparkle zipper ran smoothly during my testing period, no matter how dry and dusty the ride, and the Spacelink kept my stem bag sturdy and locked in place over all types of terrain. The Cuben Fiber Hybrid is the ultimate in ultralight frame bags, at least for now, so anyone pursuing a future in crazy lightweight gear or endurance racing ought to check it out.

Build Kit

Bearclaw doesn’t hold back when it comes to the different build kits available. Like most bikes in this category, the stock 42T chainring was a bit too large for loaded bikepacking and singletrack, so I swapped that out for Wolftooth’s CAMO System and a 32T ring. As mentioned earlier, the stock Thomson Alloy bar’s drop was a bit too big for me, and I would have preferred a carbon alternative for some added comfort. The Industry Nine wheelset is bombproof, lightweight, and the tubeless setup from Bearclaw held up great over the testing period. I’m always happy to see a SRAM Force drivetrain and brakes, although I was dealing with some notoriously squeaky brake pads by the end of my demo. All in all, it’s a great blend of lightweight and performance-oriented parts, and if I were to spec one out with Bearclaw again, it would likely only include the changes I mentioned above.

  • FRAME 3AL-2.5V double-butted titanium frame
  • SIZES 48,51,52.5,54,55.5,57,58.5,60
  • FORK Bearclaw RAMHORN Full Carbon Post Mount Disc
  • CRANKSET SRAM Force 1 X-Sync
  • CHAINRING 42T X-Sync
  • B/B SRAM PF30
  • Cassette SRAM PG1130 11-42 11spd
  • Derailleur SRAM Force 1
  • FRONT BRAKE ROTOR SRAM Centerline 160mm
  • REAR BRAKE ROTOR SRAM Centerline 180mm
  • HEADSET Chris King Dropset 2
  • HANDLEBAR Thomson Alloy Dirt Drop
  • STEM Thomson Elite
  • SEATPOST Bearclaw Titanium
  • SEAT CLAMP Thomson
  • GRIPS Easton Tape
  • SADDLE WTB Volt Titanium
  • FRONT HUB Industry Nine Torch Classic 100x12mm
  • REAR HUB Industry Nine Torch Classic 142x12mm
  • SPOKES Industry Nine UltraLite 235 Wheelset
  • RIMS Industry Nine UltraLite 235 Wheelset
  • FRONT TIRE Schwalbe Thunder Burt 27.5×2.25
  • REAR TIRE Schwalbe Thunder Burt 27.5×2.25

It’s worth mentioning that Bearclaw offers custom builds on any of their frames, so you have the option to mix and match to get the perfect bike for you. I’ve been told that over half of their builds have been custom, so mix and match away. Pick a build from their website or start from scratch, the choice is yours. This falls in line with Jason’s approach, and is an added bonus of purchasing from a smaller company. Also, Bearclaw listened, and the PF30 bottom bracket will now only exist on early models (some of which are still available). Newer frames will come spec’d with a threaded bottom bracket

Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review


  • Extremely versatile. Comfortable, yet performance-oriented geometry with the ability to run a huge range of wheel / tire sizes.
  • Huge tire clearance, with room for 700x46c all the way up to 27.5×2.4”.
  • Build kits make sense for the bike, and are priced accordingly.
  • High-quality titanium frame with an obvious attention to detail and superb craftsmanship.
  • New carbon fork is fantastic, offers lots of clearance and mounts.
  • Large front triangle easily holds two bottles and a half frame bag, or one gigantic frame bag.


  • Front ring too large for bikepacking. I immediately swapped out the 40T chainring for a 32T to match my riding style.
  • Seat tube bottle mount is almost too low for certain bottle cages. My King Cage Bottle Drop Cage didn’t clear the downtube.
  • Thomson Alloy Dirt Drop Bars weren’t that comfortable when tackling long descents.
  • Model/Size Tested Bearclaw Thunderhawk Force 1 MTB, 58.5
  • Weight (as tested) 20.62 pounds (9.35 kg)
  • Rider Height/Weight 6’1″/185 lb (185cm/84kg)
  • Price $5,500
  • Place of Manufacture Taiwan
  • Manufacturer’s Details
Bearclaw Thunderhawk Review

Wrap Up

I’ve had a lot of people reach out in the last couple months to ask about my experience with the Thunderhawk. It has been compared to the Salsa Warbird, Chumba Terlingua, the Kona Rove and Sutra LTD, and even the Why Cycles R+. The Bearclaw Thunderhawk shares a few unmistakable features with the bikes mentioned above, but also differs from each, and other 650B monstercross bikes as well. First off, working with Jason at Bearclaw was enjoyable and easy, and it’s obvious that he’s passionate about creating an experience that is as close to custom as you can get. The off-the-shelf builds are appropriate for the bike, and although a stem or chainring swap may be necessary, the prices make sense.

As my first long-term review on a titanium bike, I am happy to report that the smooth riding, light weight, and durable characteristics you’d expect from a bike of this calibre definitely shone through. From short rips on Colorado singletrack to the 300-mile Julian Bikepack Challenge, and lots more in between, I was never worried about my overall comfort on the Thunderhawk. Accompanied by a high quality wheelset and the 2.25” Thunder Burts, I often found myself clearing obstacles and technical trails that were better suited for a hardtail mountain bike. It’s a very capable bike, and appears to be adaptable to all kinds of different riding preferences and conditions. I’m interested to see what else Bearclaw has up their sleeves, and what other whacky product names surface in the near future.

  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review
  • Bearclaw Thunderhawk Review

Updates for 2019 Bearclaw Thunderhawk: Moving forward, there a few changes that Bearclaw has made to the Thunderhawk that differ from the model we tested. First, the press-fit bottom bracket will be changed to a threaded 68mm shell. Also, all three bottle mounts on the frame will be updated to three-pack anything cage mounts. Jason also let us know that all frames and builds will include a Chris King Dropset 2 headset. Prefer the version we tested? As of January 5th, 2019, Bearclaw still has a few original Thunderhawks available!

Miles Arbour

Rider Profile

Currently housesitting in Maple Ridge, British Columbia, Miles enjoys riding flowy singletrack, exploring service roads, and often finds himself further from home than he planned. The Bearclaw Thunderhawk was loaned to Miles for this review.

  • Height: 6’1” (185 CM)
  • Weight: 185 lbs (84 KG)
  • Inseam: 33” (83.8 CM)
  • Current Location: Maple Ridge, BC
  • Daily Driver: Surly Karate Monkey
  • Favorite Route: Vapor Trail


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