Review of Co-op Cycles DRT 4.1 Fat Bike

The Co-op Cycles' DRT series has received a brand-new update — the DRT 4.1 fat bike

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Jeff Balton |
Co-op cycles DRT 4.1

Co-op Cycles DRT 4.1 fat bike

The Co-op Cycles’ DRT series has received a brand-new update — the DRT 4.1 fat bike. Ride longer, harder, and get out there all year round with this capable yet affordable fat-tire bike.

The DRT series is a selection of budget mountain bikes made by Co-op Cycles, a cycling brand founded by REI. It consists of rigid, hardtail, and full-suspension entry-level and mid-range two-wheelers.

Until recently, there was one piece of the puzzle missing — a purebred fat bike.

In comes the DRT 4.1! It’s a proper fat bike characterized by a compliant aluminum frame, massive tires, Shimano and SRAM components, and an affordable price tag.

If you want to roll over roots, rocks, sand, mud, or snow and enjoy doing it, DRT 4.1 is the bike that can make that happen for you.


Co-op Cycles DRT 4.1 Key specs

Frame: 6061 Aluminum
Fork: 6061 Aluminum, Rigid
Bottom Bracket: SRAM DUB English BSA 100mm fat
Crankset: SRAM X1 1000 Eagle™ DUB fat 5
Rear Derailleur: SRAM SX Eagle
Rear Cogs: SRAM Eagle, 11-50t
Number of Gears: 12
Brakes: Shimano Acera MT-400 hydraulic disc
Tires: Innova 26 x 4.8 in.; 60 TPI
Saddle: WTB Pure Sport
Weight: 39 lbs.


Who Is the Co-op Cycles DRT 4.1 For?

DRT 4.1 fat mountain bike

The DRT 4.1 fat-tire bike is FAT in every possible way. It has huge tires, a burly frame, sturdy aluminum rims, disc brakes, and a plentitude of mounting points. As a result, it weighs 39 lbs. which is not much given its sturdy.

However, it’s not a bike for those who want to be quick, nimble, and ride fast. But it’s definitely the right choice for anyone who wants to keep riding when the majority of other mountain bikers have to turn around and look for a more manageable route.

Co-op Cycles is an outdoor-oriented brand, so it makes sense that they put an effort to make DRT 4.1 ready for long bikepacking adventures. You can equip it with fenders, racks, and several water bottle cages on both the frame and the fork.

It will allow you to keep riding come rain or shine, no matter the season, the temperature, or the conditions.


Co-op Cycles DRT 4.1 Review Highlights

Like all other members of the DRT line, DRT 4.1 is very attractively priced at $1,300. One thing that we can expect from it, taught by experience, is a fantastic value for the money.

Co-op did not cut corners with this bike, even though they could not splurge either, as that would spike the price.

As a result, off-road enthusiasts get a 1×12 drivetrain, hydro brakes, tubeless-ready rims and tires, aluminum, and a few other surprises we’ll mention below.


Strong and Rigid Aluminum Frame

drt 4.1 aluminum frame

Building fat bikes around traditional steel frames is a popular trend nowadays. Nonetheless, Co-op Cycles decided to make DRT 4.1 with lightweight 6061 aluminum.

As a result, this bike weighs 39 lbs., which is not lightweight by any means, but it is significantly lighter than many of its competitors in the same price range.

The fork is rigid and made of aluminum as well. All of the cables are fully internally routed, which brings out the bright orange paint job and really makes it pop.

All in all, it’s a comfortable and simple frame, with a relaxed geometry, as one would expect to see on a fat bike.


12-Speed Drivetrain

drt 4.1 SRAM SX 12-speed drivetrainFor the drivetrain, Co-op decided to go with SRAM’s 12-speed SX Eagle groupset. That makes a lot of sense, as SX Eagle is the cheapest 12-speed group SRAM offers at the moment.


Therefore, you get both cost savings and a wide range of gears, at the expense of a slightly higher weight compared to the NX group.

The 11-50t cassette combined with the 30T crankset will give you a wide range of easy gears to choose from and climb whatever hill gets in your way.


Impressive 4.8″ Tires

Co-op drt 4.1 fat tires

As it befits a fat-tire bike, Co-op Cycles DRT 4.1 rolls on super plush 4.8″ tires with 60 TPI. These are made by Innova and wrapped around 26″ aluminum rims. The combo is definitely not light, but both the wheels and the tires are tubeless-ready, so rocks and roots won’t give you pinch flats.

The Innova tires in question do not have very pronounced and aggressive knobs, which makes them ideal for solid surfaces, such as hard-packed dirt and gravel. Still, if you deflate them to around 15 PSI, you’ll have no problem riding on soft snow, mud, or sand either.

Related: Best Fat Tire Electric Bikes


Front & Rear Thru Axles

One seemingly small thing that gives the DRT 4.1 fat bike a bike advantage is front and rear thru-axles. Fat bikes endure much more abuse than regular bikes, which is why this is an important detail.

Thru-axles make the bike a lot more stable compared to quick-release axles. Plus, the wheels become stronger and more rigid as well, which you’ll appreciate when you start navigating rocks and roots.


Shimano Hydraulic Disc Brakes

drt 4.1 with hydraulic disc brakes

The last piece of the puzzle we should talk about is the Shimano Acera MT-400 hydraulic disc brakes that DRT 4.1 comes with.

These are two-piston brakes that Shimano made exclusively for trail riding. Therefore, they are easy to set up and offer controlled and predictable braking performance. The levers come with an adjustable reach, so you can fit them to your liking.


Ready for Bikepacking Adventures

The bikepacking culture is on the rise, as more and more people are realizing the benefits of traveling light, through scenic and remote areas, away from busy roads and cities.

If you want to really go off the beaten path, where few have ridden before, Co-op Cycles DRT 4.1 might be the right choice of transportation.

Apart from the huge tires and sturdy frame that can handle up to 300 lbs. of weight, DRT 4.1 can easily get accessorized.

You can fit it with a front and rear rack, front and rear fenders, and two water bottles inside the front triangle. The fork features triple-eyelet mounts, so you can attach additional carriers on the front.

Moreover, the thru-axles make the build strong and stable under heavy load, and the 1×12 drivetrain will give you enough granny gears to keep pedaling when hills become steep.


Geometry and Handling

Unsurprisingly, the DRT 4.1 fat bike has a rather slack geometry with a 68° head tube angle. As a result, the wheelbase is 1100mm to 1215mm long, depending on the size, which will make you more stable while stomping over obstacles.

However, the 72° seat tube angle ensures that you’re riding in a comfortable upright position, so you can keep pedaling all day long, without fatigue.

The bike is available in five frame sizes indicated as XS, S, M, L, and XL. There are no heigh-based sizing recommendations, but you can choose the right size based on the stack and reach.

You can also refer to Co-op Cycles’ general MTB sizing chart to get an idea of which size to get:

Inches 4’9″ – 5’0″ 5’0″ – 5’3″ 5’3″ – 5’6″ 5’6″ – 5’9″ 5’9″ – 6’0″ 6’0″ – 6’3″
Centimeters 145cm – 152cm 152cm – 160cm 160cm – 168cm 168cm – 175cm 175cm – 183cm
183cm – 190cm+


Is Co-op Cycles DRT 4.1 a Good Buy?

Co-op Cycles DRT 4.1 is going to become a best-seller in the fat bike category in no time — there’s no doubt about it.

drt 4.1 bikepacking bike

It combines low price, high value, quality Shimano and SRAM components, a versatile build, and phenomenal looks, so it has all the necessary features to get sold out quickly.

If you’re a recreational rider and you need a bike to go on bikepacking trips or simply ride all the time, no matter the weather and the conditions, you can’t go wrong with DRT 4.1.

Co-op Cycles DRT 4.1













  • Excellent aluminum frame
  • Massive Innova 4.8" tires
  • 12-speed drivetrain
  • Hydraulic disc brakes
  • Thru-axles


  • Rather heavy wheels

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