Bike Review: Mongoose Dolomite Fat Tire Bike

As an avid year-round biker many people would question why I would buy a $200 fat bike as my first foray into fat biking. Well, I'm cheap.  I'll be honest. I already have a custom-built winter bike that I use as my daily commuter, but I wanted something fun, and a solid base for building what I wanted over time. Well, this is certainly that bike.  The Dolomite is the least expensive fat bike that is on the market.  I paid ~$215 shipped to my house!

Unpacking:

When shipped, this bike comes in a HUGE box and weighs 59 lbs.  I happened to see the FedEx driver when she delivered it, so I helped carry it in, but it is manageable by one person.

Box when delivered:

The bike ships basically complete, but the front wheel and handle bars are not connected.  

Once removed from the box it looks like this: 

You'll have to remove all the packing materials, then the fun part begins!

After you get all the packing materials removed, you're ready to start the dry assembly.  I have a professional bike stand, but it is simple enough to be done while the bike is on the ground.

Assembly: 

So, I'll be the first to admit, I never looked at the manual. The assembly is pretty straight-forward.  You could just put the front wheel on (15mm bolts), attached the handle bars (4mm allen), straighten the headset (5mm allen), and start riding, but that would not be a great option.  Because the bike is cheap, there is basically no lubrication on any of the components, so riding it out of the box may not be the best idea...

Starting from the front, let's checkout the headset.  Loosen or remove the stem from the headset.  Note that once you remove the stem, the fork should come loose (it may require a tap or two with a rubber mallet), however you don't need to completely remove the fork to add the grease. Once you have the fork free, check out the bearings in the upper and lower headset races.  For me, there was basically no grease on either of these bearings.  I quick used some marine bearing grease and a toothbrush and liberally added grease to both of these areas.

Here is an example of my lower headset race, after grease application:

The next steps do require some speciality bike tools.  Nothing too expensive, and certainly tools you will want to have, however, you won't be able to do much without them...

The tools I used are as follows:

• 15mm Cone wrench (ideally you would have 2) $5/ea
• Park Tools bottom bracket hook spanner (HCW-5) $15
• Park Tools Hyperglide Lockring tool (FR-5) $6

Again, starting with the front, let's check out the front wheel.  With a cone wrench, back off the retaining nut and check out the bearings.  Be careful when removing the nut, as the actual ball bearings may fall out, so make sure to complete one side at a time, and leave that side upright.  My bet is that once you are looking at the bearings there is very little grease present.   

Use your toothbrush with ample bearing grease and grease one side, tighten down the cone (not too tight, just tight enough to seal the bearing), and do the same on the other side of the front wheel.  You should notice that the wheel rolls WAY smoother now. If you overtightened the cone, you will notice that the wheel doesn't freespin very well.  Just loosen cones a little at the time until the wheel feels like it has minimal resistance. 

Once the front wheel is completed, move onto the bottom bracket.  Because this is a very inexpensive, it neither has a sealed BB, nor does it have a cartridge like most bikes, the bearings are exposed once you remove the threaded "bracket".  

Grab your hook spanner, and remove the retention ring on the left side (not the chain-side) of the bike.  Not back off the BB using a 15mm wrench.  Again, be careful with this as the bearings may fall out.  Using the toothbrush, add copious amounts of bearing grease, the more the better!  Because this isn't a sealed cartridge, the grease will help to keep to extend the life of the bearings.  

Bottom bracket disassembled:

If you're lazy, you can actually add grease to both sides, while only actually pulling one side.  When the left side is out, put a ton of grease of your toothbrush and smear it on the inside of the right side bearing.  This isn't an ideal option, but it's easy and will work for most purposes. 

Reassemble the BB, making sure to tighten the BB so it's secure, but not super tight.  If it's really tight, you will notice it doesn't freespin very easy. 

Finally, move onto the real wheel.  The left side of the wheel will be the exact same as what you did on the front wheel.  Use your cone tool and loosen it up and add grease. The cassette side however will be a bit more challenging. 

Rear wheel:

Using cone tool, remove the cone for the right side of the rear wheel.  Then remove the cassette using the lockring tool.  Once removed, add a ton of grease onto the bearings.  Remember not to over tighten everything!  

Reinstall the front and rear wheels and double check the BB to make sure it's tight and secured. 

Adjustments:     

I actually found that there wasn't a ton of adjustments that needed to be made.  However, I did have to adjust the disc brakes as they were both rubbing after assembly. 

Disc brakes are very simple overall, and generally self adjusting but need to be setup correctly to prevent premature wear and friction. If you look at the disc caliper, there are four mounting bolts. Two are on the outside of the bike, and two are facing upwards.  To adjust the "fit" of the caliper you only need to worry about the two 5mm allen bolts facing upwards. 

Start with one wheel, and loosed the two 5mm upward allen bolts. Spin the wheel and move the caliper until the caliper no longer rubs on the disc. Once you find that magic spot, tighten down the allen bolts and do the same for the other wheel. 

Conclusions: 

Once the bike is assembled and adjusted it's not too terrible.  The components are definitely cheap, but that's to be expected.  I was also a bit saddened by the fact my bike came pre-scratched from shipping/factory handling. 

Just sitting on the bike, with the brakes locked, I could feel play in the cassette.  Others have said that this is an early fail point, and I can see that too. I already have a spare 8 speed cassette, and shifters, so that may go on pretty soon. 

I haven't ridden the bike yet, but I will surely be able to say more once it gets some miles on the tires.  My goal is to keep costs to a minimum while getting the same enjoyment as those that spend thousands.  I am positive I can do it.