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Mongoose Juneau Fat Bike Review and Upgrades

The Moongoose Juneau is a lot of bike for the price. It can often be found for less than $300. The price on Amazon seems to fluctuate up and down. It will drop down as low as about $260 and then bounce back up to over $700.

It's a very nice bike (for under $500), and it only gets better the lower the price goes.


▶ Thudbuster LT Seatpost (Amazon)


Assembling this bike is very easy, and it comes with good instructions. It arrives with the handlebars, seatpost, front wheel and pedals removed.

  • Handlebars require an Allen hex wrench to install and ideally a troque wrench to tighten up to the proper torque.

  • Seatpost clamp uses a quick release so it is easy to install.

  • The front wheel uses a quick release skewer and is therefore easy to attach.

  • The pedals require a narrow wrench (pedal wrench is ideal) to tighten them.


The frame is all aluminum, lightweight, and very well made. The drop outs are designed for quick release skewers, so not the strongest design. Through axles would be nicer and add strength to the frame.

The frame is not designed for a suspension fork, and as such does not have the clearance required to prevent the fork from hitting the frame.

The headset is designed for standard straight tube steerer. It won't work with a tapered steerer tube as most modern quality suspension forks have.


The bike has disc brakes and has a larger 180mm rotor in the front and a standard 160mm rotor in the rear. The braking power is not as good as it could be. Breaking in the brake pads by going fast and coming to a hard stop 5-10 times will help improve the breaking force. I noticed that the stock break pads ride close to the edge of the rotor, and dont utilize their full surface area.

Replacing the brake pads with Shimano resin pads makes a huge improvement in braking power. The Shimano brake pads provide significantly more braking force. Whereas with the stock brake pads it's difficult to lock up the tires on asphalt, the Shimano resin brake pads will easily lock up the wheels. It's a cheap and worthwhile upgrade.


The gears are pretty decent on the Mongoose Juneau. It has 16 speeds. 2 chainrings in the front and 8 sprockets on the rear cassette. Since it does have a cassette, there are more quality options available for rear sprockets. The lowest gears are suitable for mountain bike climbing.


Dropper Seatpost (With Suspension)

I was debating between adding a dropper seatpost or a suspension seatpost. The fat tires do a good job of soaking up vibration and small bumps, but when they are soft enough to do so, they also have no damping, so it feels like riding a basketball. A suspension seatpost would still be nice since it's a hardtail and then I can bump up the tire pressure. I also wanted a dropper seatpost for descents and making the bike feel more playful.

I found the best of both worlds with the PNW Coast dropper seatpost and suspension combination. The 31.6mm diameter version has 120mm drop + 40mm of suspension travel. That's more suspension travel than most good suspension seatposts. However, many reviews say that the suspension is not active and only good for hard hits, and there's no damping.

PNW seatposts do not come with a lever, so be prepared to buy one. Fortunately dropper seat post levers are fairly cross compatible, as long as you have the type where the cable gets cut at the lever, and has the terminating ball at the seatpost.

I like the Crank Brothers Highline Dropper Post Remote Lever, because it seems very adjustable which is important with an already crowded handlebar, it can be difficult to fit the lever, and even harder to get it in the right position.

The easiest installation option is to use an external dropper seatpost, and zip tie the cables to the current cables. I did find an excellent deal on an internally routed PNC coast dropper seatpost, which would require drilling holes in the frame and installing grommets. The path I would take would be to drill a hole in the lower rear seat tube, pass the cable under the bottom bracket, enter the down tube near the bottom bracket, go up the down tube, and exit out the opposite side of the downtube from where the lever will be installed. These Salsa brand grommets would work.

Suspension Seatpost

Even with the fat tires reducing a lot of the small bumps, the fat tires are definitely not a full suspension replacement.

The Cane Creek Thudbuster LT is a good match for a fat bike.


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