# Front hub motor for fatbikes (15x150 through axle)



## SurlyNate (Mar 16, 2006)

Does anyone know of a drop-in solution for a front hub motor for a 15x150mm through axle? Looking for something for my Big Fat Dummy to aid in hauling tools for trail work, but want something simpler than mid-drive setup with all the associated complexity. Just need a bit of assistance. 

Thanks!


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## high_desert_mud (Jul 22, 2017)

Doesn't exist, not for your application 

I *JUST* set myself up for the exact same bike (BFD is the best bike i've ever owned - likely the best bike ever created  )

What i did is replace my fork with a steel 135mm (eg Classic Mtn Rear) fork, and build a rear non-offset-side wheel on a rear motor. I swap the motor on/off, so i pressed on a crown race, and replace the whole front fork.

What i 
My build:

Grin GMAC build (proper torque arm, _geared_ regen braking can bring whole bike to a stop by itself, power capable to be durable long term on a loaded bike
PhaseRunner controller
52v 14ah 52v pack (the 21700 model was on sale)
 soma battleaxe 135 fork. Might replace with a surly fork when the non-side-offset versions get back in stock. (the three options i found that could be had new: surly pugs or moonlander NONoffset (not in stock), soma battleaxe (some old stock to be found), and a steel fork off of a tumbleweed bike (can be bought new, in-stock).

Some details:

Cargo is a challenging application, for both torque & weight load, as well as power. This limits your realistic options. Grin strongly advised against an small motor such as g301, for instance, even though I am only wanted a "1x human" (~250w MAX) build)
regen braking is a huge plus, to save/augment the brakes (only ~10% range recoupe MAX, likely ~5%)

hope that helps! Look at my thread history for more details, i asked some of the same questions here.


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## high_desert_mud (Jul 22, 2017)

Forgot to mention: the best option I found for thru axle was the grin "all axle" motor - I passed and went 135 because:
- as Grin (ebikes.ca) points out, to support the wider axles in that particular design, they have to use weaker bearings (*AND* the wheel must be de-laced to service  )
- it can not regen. Compared to the GMAC which takes a ton of load off my brakes.


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