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Trail Tested: Diamond Back El Oso Grande Fatbike

Usually when a new year rolls around, many people resolve to lose a few pounds. I’m going to suggest the opposite and recommend you get gloriously fat. You should get El Oso Grande fat to be specific.

This is not the first fatbike we’ve featured on Expedition Portal. By my count I believe this is the fifth, but it is unique in one very particular way––it’s attainable. I often joke that fatbikes are sold in three pricing levels. At the bottom is expensive and above that sits cost prohibitive. At the top is a range of prices I classify under the header of, divorce court. Spend those funds at your own peril and see what the spouse has to say about it. At $1,700, the El Oso Grande doesn’t even register as truly expensive. It’s quite literally a lot of bike for the cash.

With a hydroformed 6061-T6 aluminum frame and fork, the El Oso Grande qualifies as a full fat platform due to its 95mm rims and plump 4.9-inch tires. Helping to push that big meat down the trail is a 2×10 drivetrain using a mix of SRAM X5, FSA, and Shimano components. The TRP cable-actuated disc brakes keep things mechanically simple and are paired to 160mm rotors front and rear. Overall, it’s a nicely sorted bike offered for a reasonable ask.

We first took delivery of our test bike last spring and over the course of the summer and fall we have come to appreciate it based almost exclusively on fun-factor. There is no denying you get what you pay for in life, and that certainly applies to the bike world. A $1,700 fatbike does have modest limitations. For starters, she’s a weighty beast. Much of that can be attributed to entry level tires and the rather enormous tubes within, but the whole package with intermediate level components is quite heavy at 36 pounds.


For typical fatbike fun, the El Oso Grande provides all of the benefits of a big-tired bike. Floatation on the softest surfaces is excellent. Sand and snow are no match for the 4.9-inch tires and the low 26×36-tooth gear ratio offers ample low range oomph to push through those conditions. The frame has several nice appointments like triple-bolt mounting bosses on the fork blades to accommodate bottle or cargo cages. The main triangle is large enough to fit a generously sized frame bag, and the rear stays have well positioned rack mounts for those riders inclined to venture far afield with more stuff on board.

Big bikes like these have to be thoughtfully engineered as to not feel sluggish or prone to flex under the forces of the big wheels. The El Oso Grande has a lively geometry which does an admirable job of accentuating the handling characteristics. That is a tough challenge given the weight of the wheels. Most users will likely upgrade the tires and extract the tubes, a worthy procedure which could potentially cull a couple of pounds.


Without flogging the heft of the El Oso Grande to death, there are is one other minor misstep. In an effort to reduce cost and complexity, the mechanical brakes are not only fitted to tiny rotors, they don’t have a ton of power or modulation to begin with. This means the mass and momentum of the bike writes checks the brakes can’t cash. Burn into a high speed corner with a bit too much enthusiasm and you will overcook the apex and likely steamroll into the bushes.

Aside from that minor grouse, the Diamondback is a lot of fun, particularly if the mission for the day is to just enjoy the ride and not set any speed records.

Who should buy it

If you have yet to wet your beak in the fatbike world and you’re not sure if it’s for you, the low entry point of the El Oso Grande makes it an attractive option. I will say, just a few hundred bucks more puts you in reach of bikes with full carbon fiber frames, but we know how that exercise goes. Plunk down an extra $200 here, then another there, and you’re back up to $3,000 or more––probably more. At $1,700 at full retail, the Diamondback is a solid value.

If you live in a part of the world with lengthy climbs, particularly steep ones, the weight is going to be a cruel task master. The brakes are going to be downright spooky, but those two drawbacks can be mitigated with a little upgrade cash, and not too much of it. It’s a very nice looking bike and would make for a great way to start off 2017.

So go get fat.


Christophe Noel is a journalist from Prescott, Arizona. Born into a family of backcountry enthusiasts, Christophe grew up backpacking the mountains and deserts of the American West. An avid cyclist and bikepacker, he also has a passion for motorcycles, travel, food and overlanding.