The cheapest fat-bike build I’ve made and the most fun to ride on dirt single-track
The favorite bike of my collection previous to this build was the Sun-Kiss Deadeye Monster that I built specifically for single-track snow riding. I wanted to build something a little lighter that would be dedicated to single-track dirt and mud and not so much for snow. What I ended up with has quickly become the favorite trail bike in my 6 electric fat-bike fleet. It is a cheap and easy build that can be done in about 6 hours and will cost less than $1000 depending on the options you chose.
Mud makes the best camouflage. Titanium axle pedals sure look out of place on a $250 bike.
Please note that every reference to Deadeye ‘Monster’ refers to my Orange Sun-Kiss build, any reference to just Deadeye I am talking about Duh Banana bike build.
Bikes Direct sells their cheapest fat-bike as the single speed Deadeye for $300. I got mine from bikeisland with a couple of shipping scratches on it for $250 which I thought was a good deal. The Deadeye 3 inch tires were the first thing I swapped out as 3″ was not big enough to make a decent suspension. The Deadeye Monster is $100 more and has Vee-Rubber Mission 4 tires (full review here) which I also dislike. Your choice is to spend $300 on a bike whose tires you won’t use or $400 on a bike whose tires you probably won’t use, the choice is yours to make.
I replaced the ‘pull adjustment’ bolts with stainless M5 bolts from McMaster car so I can use a ‘Push adjustment’ instead. Lighter weight and 1.5 cm more adjustment range.
The Deadeye frame has smaller clearance in the rear than the Deadeye monster. Although I could squeeze a Surly 4.8 Lou in the back of my Monster, the biggest tire you can fit in the rear of a stock Deadeye is a 4 inch tire. The rear tire I settled on was a 120TPI folding bead Panaracer Fat B Nimble 4.0 (review here) which I got for $53 on ebay from The Bikesmiths which is a fantastic deal for a great tire. In the front I settled on the 4.25 Vee-Rubber H-Billie which is the first Vee-Rubber tire I’ve used that hasn’t sucked, full review is here.
The nice part about the more narrow chain-stays is that you can mount a stock BBS02 on it without using an offset crankarm on the non-drive side. The same could not be said for the Deadeye Monster which has a much wider separation between chainstays. The Monster chainstay also bumps the reduction wheel of the BBS02 pushing the chain-line out a cm or so. The stock Deadeye fits the BBS02 quite nicely and flush up against the bottom bracket frame hole.
There is room for a 4.5 inch tire in the front fork, but only a 4.0 tire in the rear.
If you stick with the stock 32T front chainring and 22T rear cog you probably don’t need to install a temp sensor as it will be nearly impossible to overheat your controller. The bike tops out at 15mph (measured with a GPS) with this configuration, but you will not want to ride twisty singletrack faster than 15mph anyway so don’t worry. The single-speed setup is awesome in that you never have to worry about chain issues. The chain-line on the Deadeye is much cleaner than the Deadeye Monster and I have yet to have it come off even once. The Deadeye Monster is still giving me trouble and I’m planning to swap the stock front chainring with a 32T narrow-wide Raceface ring on that bike.
The Thudbuster LT is key for high-speed trail-riding and saving your ass.
The most important part of this setup I feel is running the tires as ghetto tubeless. This can be done for about $15/tire in 30 minutes or so, instructions are located here. This will allow you to run low pressures like 8psi in the rear and 7psi in the front and still not have to deal with pinch-flats.
Avid BB7 on the rear, I couldn’t get one to mount properly on the front without hitting the spokes.
What I paid for this setup
- $489 BBS02 from em3ev (without chainwheel) Update: Now there is a new game in town BBS02 750W for $520 from US vendor Lunacycles which ends up being cheaper when you add the shipping from China
- $25 Ballarat chainring adapter (the one I used was different but this one is cheaper)
- $250 for the Deadeye from bikeisland (I got mine with a few scratches, you can buy yours new for $300 from Bikes Direct here)
- $53 for new Panaracer Fat B Nimble 4 tire on ebay (optional but recommended)
- $51 for new Vee-Rubber H-Billie 4.25 from ebay (optional but recommended)
- $92 for used Thudbuster LT 27.2 seatpost on ebay (optional but recommended)
- $2 for Aquarium Thermometer on ebay (optional)
- $32 Rock Bro Titanium Pedals new from ebay seller cycleling (optional)
- $38 New Avid BB7 rear brake and G2 rotor on ebay from cycleling (I couldn’t get one to fit on the front)
That puts the total investment I have into my bike at $1032 without a battery and shipping for various items. This bike is way more fun to ride than electric fat-bikes I have built that cost almost three times as much. At 41 lbs this bike can be thrown around and seems to go right where I want it to. I can roll over big areas of roots at top speed without fear of losing control. The rear tire sometimes slips in thick mud but has so much traction that even on the steepest descents I rarely use my front brake.
Temp sensor
So is there a direct correlation between how much you spend on your bike and how fun it is to ride? If there is then I haven’t noticed it. To me it seems like it’s all about the weight and the tires. Folding Bead 120 TPI tires feel much better on the trail than wire bead 27 TPI tires do. A deeper tread always feels better than a shallow one. Tubeless feels MUCH better than tubes do, even ultralight tubes. Every pound you save on the bike makes it feel that much more nimble and forgiving on the trail. A single-speed for trail-riding is much better than having a bunch of gears as there is less to think about and less to go wrong while you’re riding. Although you will only be able to pedal on the steepest uphills (otherwise the cadence is too fast) and when you see other riders on the trail. Ironically most of them will not even notice that you have an electric bike unless you stop to chat with them.
For a battery pack get something that is 48V and puts out at least 30Amps continuous. If you want step by step instructions on installing a BBS02 look no farther than here.
If you want to install a Bluto suspension fork on this non-tapered headtube check out this post.
If you can live with a top speed of 15mph and don’t mind saving a few bucks then doing a build like Duh Banana bike might be perfect for you.
UPDATE: The newest Deadeye Monsters ship with a 100mm BB. Your best bet is a BBSHD 1000W system. BD website still shows a 68mm BB but the bike has changed. There is a very good chance that the Deadeye (non-monster) is also shipping with a 100mm BB so order the bike and wait for it to arrive BEFORE you buy a drive unit so you can get the right one.
Ride On
