Hi all,

Just wondering if anyone here has added a kit to a Specialized Fatboy. If so, what did you go with?

thanks!

I haven't completed such a conversion but I'd recommend a mid-drive for that bike. Probably a Bafang BB0S2 or BBSHD depending on your goals.
I have converted a Specialized Crosstrail Hybrid with a Dillenger rear hub drive. And, while it works fine a mid-drive lets you use the rear wheel drive train as your motor's transmission gears.

You'd have a difficult time finding a hub drive wheel in a kit that accommodates those tires, etc. With a mid-drive you'll keep everything more or less stock except the crankset and any front derailleur, if you have one.

The Fatboy should make a very nice eBike conversion. And, you'll find Bafang mid-drive kits available at lots of places. I'd recommend Luna Cycle, or California eBike or Dillenger bikes but they are stock items available at tons of places.

Thanks for your reply.

As I am a novice, I was leaning toward the ebikeling front tire kit for a fat bike. I have been assuming this would result in the least amount of "stock" parts removal. I assume this would still allow me to pedal manually?

Also, there is a youtube video of a guy installing a mid-drive on a Fatboy and if I understood him correctly, he was not able to use all of the gears on the back wheel.

Read up on Front Hub Drives, they are easy to install but you will find them problematic for traction. There's not a lot of weight on the front of your bike compared to the middle or the rear. And, the tire is trying to conduct steering and powering all at the same time. Loose surfaces can be big problems.

All you change on a mid-drive is the "middle" of the bike. The motor is between the pedals, mounted through the bottom bracket. You do lose the front derailleur but that will not be an issue. The rest is stock - front wheel, rear wheel, gears, derailleur are all stock. You really should be able to use ALL of the gears on the back wheel. With any conversion there can be a need to make some alterations. My bike started as a 2 by 9-speed. After installing the rear hub drive I had some problems using the 9th gear. It was a spacing issue and that one gear would skip under pressure. I did change the rear gearing to 8-speed instead of the OEM 9-speed and everything has worked perfectly since.

Theoretically, you'll have less problems like that with a mid-drive conversion - but there can always be small issues to work out on any conversion. The kits are made for a wide range of bikes. They are not custom made for "your" bike.

Ok, I did more reading and watched more videos. I'm starting to see the light now on the mid-drive. Also, regarding that guy being unable to use all the rear gears, it appears it was solely a result of his chain ring choice.

Thanks for the vendor recommendations. I'm currently picking my way through all the options on the Luna Cycle web site.

Last time I looked there was one option on the Luna site, a BBSHD which isn't a bad choice, and no 48V or 52V batteries. You might be interested in the tutorial on ebikesca. Should you decide on a mid-drive, make sure you measure the width of the bottom bracket (probably 100 mm on a Fatboy, but that's a guess). Also, be aware that depending on how the chainstays flare out, the motor may not "nestle" against the frame. It would be advisable to locate someone who has accomplished the conversion. Try endless sphere.

Hi, thanks for the reply.

Yes, it is 100mm. In the video I had referenced (youtube), the motor "touched" the frame after tightening which is a concern.

Thanks for the references....I will look into them.

I forgot to ask...what battery do you recommend for an application like this? Luna seems to offer batteries now but I keep seeing references to Bosch....

thanks...

I don't think Bosch makes batteries for any except OEM systems. I've had good luck with Luna's batteries, and would recommend 52V and at least 15 ah for a BBSHD. BTW, Luna has "out of stock" for all batteries except one 48V & one 52V, but in the description says both aren't available (unless I'm reading something wrong).

Is the Fatboy carbon? Specialized carbon bikes often have a bottom bracket housing that is too thick to slide a mid drive motor into it. You would have to measure the thickness and compare it to the specs. I would not consider a front hub drive on a fat bike as the forks are probably not strong enough.