I built a Framed Alaskan Fat Bike into a Ludicrous Commuter!
Here’s a listing of the tools and parts that went in to my build:
Tools
metric hex keys
Park BBT-9 bottom bracket tool
Park MLP-1.2 master link tool
Park CT-3 chain tool
Park CCP-1 crank puller
Park FR-5 cassette tool
Park CWP-7 compact crank puller
Chain whip
Torque wrench
Luna wrench mid-drive installation tool
Wire strippers
Shrink tubing
Soldering iron and solder
Cable cutters
Zip ties
Dremel tool grinder
Blue Lock-Tite
Most of these specialty tools i already had as I’ve built a couple of bikes over the years but some i had to buy for this build. I needed several of the Park specialty tools because i replaced the drivetrain - new cassette, derailleur, rear shifter and chain. I upgraded these to stronger ebike specific parts, see below.
Build
Bike: Framed Alaskan 2.1 Alloy Fat Bike 26” with SRAM X7 groupset. It was on a year-end close-out for a very good price. Frame size is 17”.
Motor: 100mm Bafang BBSHD with Ludicrous Controller on Black Friday Special. Thank you LUNA!!!
Chain ring: Lekkie 42T Bling Ring. I bought the Luna Eclipse 42T and its gorgeous, but I couldn’t get it to clear my chain stay so had to return it.
Display: Luna 500c Mini Full Color Display
Throttle: Luna Right Twist Full Throttle which i really like
Brake Levers: Optional Mechanical Ebrake Levers With Cut-Off
Luna Spacers and Helpers - really glad i got this, i used all the spacers
Battery: Luna Wolf v2 LG MJ1 52 V 13.5 Ah in its naked form
Charger: Luna 52V Advanced
Gear Sensor which i got on A’zon for half price and is worth the cost and effort
CNC Luna Perfect Pedals
5 feet of KMC Bike Chain with Master Link
Several 10 mm rare earth refrigerator magnets
Bike Upgrades
Fisher Fabhouse Matte Black Ultra 3200 LED E-bike Light - i recommend you get their XT-90 to XT-30 Y adapter to enable super simple connection to your battery.
X5 Rear Light with Laser
Arkel TailRider Bike Trunk
Axiom Cycling Gear Steamliner Fatliner Rack
Ortlieb Gravel Pack Panniers
Jandd Underseat Tool Bag
SRAM EX1 Trigger 8 Speed Shifter
SRAM EX1 1x8 Speed Long Cage Rear Derailleur
SRAM XG-899 E-Bike X-Glide Cassette 11-48 8 speed
SRAM 203 mm Centerline Rounded Brake Rotor
Avid 40p Post Bracket Front Brake Adapter
What Went Well
The majority of the build was pretty straightforward. I took my time and i completed it over about a week in the evening and one weekend morning. Pulling the crank and bottom bracket from the new bike was pretty simple with the right tools. There are tons of videos on-line with detailed instructions on how to do this. Likewise, replacing the cassette, derailleur and shifter with upgraded E-Bike quality parts was easy by following on-line illustrations. The swap of the front brake disc from a 160 mm to a 200 mm and spacing out the brake caliper took me a bit to figure out how to correctly position the brake but in the end it was easy. I had thought a lot about upgrading to hydraulic brakes and both my other bikes have them but the disc swap was easy and cheap and upgrading the front brake disc provides all the stopping power i need. My daily ride includes a 20% downhill grade so i wanted to be able to stop on this hill if i had to. Fortunately, the rear rack mounted easily as did the Fisher Headlight. Both my chain ring and my cassette are many teeth bigger than the micro drive the bike came with so I had to replace the chain. Figuring out how long to make the chain isn’t hard but i hadn’t done it before - i found that Park tools has great videos on how to do this and other bike repairs. Thank you Park tools!
What Took Some Thought and Effort
Initially the Bafang motor would not go in to the bottom bracket. Fortunately, I had read build reports from others who used the Framed Alaskan bike for this and they had to dremel out some of the metal inside the bracket where the seat tube and down tube join the bottom bracket. This took a few minutes to do, i kept checking the fit until i got it in on one side, then did the same from the other side of the bottom bracket. My bottom bracket is 100mm wide so i had ordered the 100mm motor to fit. Once I was able to insert it, it became obvious that the chain stay was going to prevent seating the motor correctly and fully into the bracket. Luna’s spacers solved this problem but at the expense of not having enough thread left on the right side of the bike to use the locknut Bafang provides on the bottom bracket. There are two nuts to use here, one is a lock-nut against the one that tightens the motor to the frame but I could only fit the one nut on the threads. I used blue lock-tite to hold the one nut on and will have to check it periodically to ensure it doesn’t work loose. The 120mm Extra Fat option would have worked better in this situation.
Once i had the motor installed, the next issue was the chain ring. Again, the Luna spacers helped a great deal. I could space out the 46T Bafang steel frisbee ring with one spacer and it would clear the chain stay and bonus: chain line was perfect! Right down the middle of the cassette! Better than I had hoped for. This showed me what offset I needed. There is great information on the electricbike forum on chain ring offset that helped me to pick out the right chain ring. I wanted a 42 tooth chain ring as a good compromise with speed and torque, but it had to work of course. The Bafang 46T frisbee offset is 19 mm and Luna Eclipse 42T offset is 24.8 mm. Those extra 5.8 mm (about 1/4 inch) prevented me from using the Eclipse that i had ordered with the build kit. Sadly i had to return it. Fortunately, the Lekkie 42T Bling Ring has a 20.4 mm offset and is also 16mm smaller in diameter than the Bafang 46T. The Bling Ring worked beautifully with one chain ring spacer and gives me perfect chain line. My bike shifts without any problems across the full cassette. I found a Bafang install video on line for the gear sensor and also installed that. Glad i did as it works well by momentarily cutting motor power during a shift to avoid slamming the drive train by shifting under load.
Two other small things needed a bit of thought to solve. The speed sensor needs to be close to the spokes (couple mm actually) because thats where the magnet mounts that is used to measure wheel rpm as it flies around. My fat friend doesn’t really have the chain stays close enough to the wheel to allow that to work. So, I epoxied a magnet to the rim of the wheel and stacked two more of these little 10mm rare earth magnets on top of the epoxied one. Works great and so far they haven’t fallen off. If one does fall off, I bought a box of 250 of them from Amazon, so i have a few spares to use. Last challenge was the X5 rear light would be totally blocked by my trunk bag if i mounted it on the seat post as its intended to be mounted. I cut and drilled out a couple of “L” steel brackets from the hardware store and screwed them to the back of the rack. This made a substitute mount where I could attach the X5 to the rear of the rack.
How Does it Ride?
I have a 34 mile round trip commute that crosses the 5.5 mile long Richmond San Rafael bridge over the San Francisco Bay. Caltrans just opened a bike line in November 2019 on the bridge so for the first time in 25 years i can now bike to work. As I said above, I also have a pretty steep hill at the last half mile to my house since i live on a ridge top so i wanted a bike that could handle the climb and the distance. I’ve been a biker my whole life and have had at least 10 bikes over the years. This one is really special. The fat tires make the ride really comfortable and the Ludicrous upgrade provides very generous power. This bike will wheelie! I can ride up that steep grade at 12 mph with only level 6 assist. On the bridge, I can hit 30+ mph on the downhills and rode up the climb at 20 mph. Round trip uses 50% of a full charge on my battery. This bike is exactly what I was hoping for. Thank you!
Some more photos:
Spacers on drive side.
Bafang Frisbee and Motor Finally Clears Chain Stay
Custom Bracket for Taillight:
Magnets on wheel rim:
Here’s a listing of the tools and parts that went in to my build:
Tools
metric hex keys
Park BBT-9 bottom bracket tool
Park MLP-1.2 master link tool
Park CT-3 chain tool
Park CCP-1 crank puller
Park FR-5 cassette tool
Park CWP-7 compact crank puller
Chain whip
Torque wrench
Luna wrench mid-drive installation tool
Wire strippers
Shrink tubing
Soldering iron and solder
Cable cutters
Zip ties
Dremel tool grinder
Blue Lock-Tite
Most of these specialty tools i already had as I’ve built a couple of bikes over the years but some i had to buy for this build. I needed several of the Park specialty tools because i replaced the drivetrain - new cassette, derailleur, rear shifter and chain. I upgraded these to stronger ebike specific parts, see below.
Build
Bike: Framed Alaskan 2.1 Alloy Fat Bike 26” with SRAM X7 groupset. It was on a year-end close-out for a very good price. Frame size is 17”.
Motor: 100mm Bafang BBSHD with Ludicrous Controller on Black Friday Special. Thank you LUNA!!!
Chain ring: Lekkie 42T Bling Ring. I bought the Luna Eclipse 42T and its gorgeous, but I couldn’t get it to clear my chain stay so had to return it.
Display: Luna 500c Mini Full Color Display
Throttle: Luna Right Twist Full Throttle which i really like
Brake Levers: Optional Mechanical Ebrake Levers With Cut-Off
Luna Spacers and Helpers - really glad i got this, i used all the spacers
Battery: Luna Wolf v2 LG MJ1 52 V 13.5 Ah in its naked form
Charger: Luna 52V Advanced
Gear Sensor which i got on A’zon for half price and is worth the cost and effort
CNC Luna Perfect Pedals
5 feet of KMC Bike Chain with Master Link
Several 10 mm rare earth refrigerator magnets
Bike Upgrades
Fisher Fabhouse Matte Black Ultra 3200 LED E-bike Light - i recommend you get their XT-90 to XT-30 Y adapter to enable super simple connection to your battery.
X5 Rear Light with Laser
Arkel TailRider Bike Trunk
Axiom Cycling Gear Steamliner Fatliner Rack
Ortlieb Gravel Pack Panniers
Jandd Underseat Tool Bag
SRAM EX1 Trigger 8 Speed Shifter
SRAM EX1 1x8 Speed Long Cage Rear Derailleur
SRAM XG-899 E-Bike X-Glide Cassette 11-48 8 speed
SRAM 203 mm Centerline Rounded Brake Rotor
Avid 40p Post Bracket Front Brake Adapter
What Went Well
The majority of the build was pretty straightforward. I took my time and i completed it over about a week in the evening and one weekend morning. Pulling the crank and bottom bracket from the new bike was pretty simple with the right tools. There are tons of videos on-line with detailed instructions on how to do this. Likewise, replacing the cassette, derailleur and shifter with upgraded E-Bike quality parts was easy by following on-line illustrations. The swap of the front brake disc from a 160 mm to a 200 mm and spacing out the brake caliper took me a bit to figure out how to correctly position the brake but in the end it was easy. I had thought a lot about upgrading to hydraulic brakes and both my other bikes have them but the disc swap was easy and cheap and upgrading the front brake disc provides all the stopping power i need. My daily ride includes a 20% downhill grade so i wanted to be able to stop on this hill if i had to. Fortunately, the rear rack mounted easily as did the Fisher Headlight. Both my chain ring and my cassette are many teeth bigger than the micro drive the bike came with so I had to replace the chain. Figuring out how long to make the chain isn’t hard but i hadn’t done it before - i found that Park tools has great videos on how to do this and other bike repairs. Thank you Park tools!
What Took Some Thought and Effort
Initially the Bafang motor would not go in to the bottom bracket. Fortunately, I had read build reports from others who used the Framed Alaskan bike for this and they had to dremel out some of the metal inside the bracket where the seat tube and down tube join the bottom bracket. This took a few minutes to do, i kept checking the fit until i got it in on one side, then did the same from the other side of the bottom bracket. My bottom bracket is 100mm wide so i had ordered the 100mm motor to fit. Once I was able to insert it, it became obvious that the chain stay was going to prevent seating the motor correctly and fully into the bracket. Luna’s spacers solved this problem but at the expense of not having enough thread left on the right side of the bike to use the locknut Bafang provides on the bottom bracket. There are two nuts to use here, one is a lock-nut against the one that tightens the motor to the frame but I could only fit the one nut on the threads. I used blue lock-tite to hold the one nut on and will have to check it periodically to ensure it doesn’t work loose. The 120mm Extra Fat option would have worked better in this situation.
Once i had the motor installed, the next issue was the chain ring. Again, the Luna spacers helped a great deal. I could space out the 46T Bafang steel frisbee ring with one spacer and it would clear the chain stay and bonus: chain line was perfect! Right down the middle of the cassette! Better than I had hoped for. This showed me what offset I needed. There is great information on the electricbike forum on chain ring offset that helped me to pick out the right chain ring. I wanted a 42 tooth chain ring as a good compromise with speed and torque, but it had to work of course. The Bafang 46T frisbee offset is 19 mm and Luna Eclipse 42T offset is 24.8 mm. Those extra 5.8 mm (about 1/4 inch) prevented me from using the Eclipse that i had ordered with the build kit. Sadly i had to return it. Fortunately, the Lekkie 42T Bling Ring has a 20.4 mm offset and is also 16mm smaller in diameter than the Bafang 46T. The Bling Ring worked beautifully with one chain ring spacer and gives me perfect chain line. My bike shifts without any problems across the full cassette. I found a Bafang install video on line for the gear sensor and also installed that. Glad i did as it works well by momentarily cutting motor power during a shift to avoid slamming the drive train by shifting under load.
Two other small things needed a bit of thought to solve. The speed sensor needs to be close to the spokes (couple mm actually) because thats where the magnet mounts that is used to measure wheel rpm as it flies around. My fat friend doesn’t really have the chain stays close enough to the wheel to allow that to work. So, I epoxied a magnet to the rim of the wheel and stacked two more of these little 10mm rare earth magnets on top of the epoxied one. Works great and so far they haven’t fallen off. If one does fall off, I bought a box of 250 of them from Amazon, so i have a few spares to use. Last challenge was the X5 rear light would be totally blocked by my trunk bag if i mounted it on the seat post as its intended to be mounted. I cut and drilled out a couple of “L” steel brackets from the hardware store and screwed them to the back of the rack. This made a substitute mount where I could attach the X5 to the rear of the rack.
How Does it Ride?
I have a 34 mile round trip commute that crosses the 5.5 mile long Richmond San Rafael bridge over the San Francisco Bay. Caltrans just opened a bike line in November 2019 on the bridge so for the first time in 25 years i can now bike to work. As I said above, I also have a pretty steep hill at the last half mile to my house since i live on a ridge top so i wanted a bike that could handle the climb and the distance. I’ve been a biker my whole life and have had at least 10 bikes over the years. This one is really special. The fat tires make the ride really comfortable and the Ludicrous upgrade provides very generous power. This bike will wheelie! I can ride up that steep grade at 12 mph with only level 6 assist. On the bridge, I can hit 30+ mph on the downhills and rode up the climb at 20 mph. Round trip uses 50% of a full charge on my battery. This bike is exactly what I was hoping for. Thank you!
Some more photos:
Spacers on drive side.
Bafang Frisbee and Motor Finally Clears Chain Stay
Custom Bracket for Taillight:
Magnets on wheel rim: