The Final Form?

[jonpad01]

This will be my 4th bike frame. List of major components:

-Fucare Taurus frame and front fork (26" fat bike) (have this)
-3shul C350 V4 controller (have this)
-QS 205 4T Motor with the 175mm axle (waiting on this)
-Home made battery - 72v 30ah (20s7p) using molicel p42a cells (waiting on parts)

Some special pieces that I want on the system:

-Need a 120mm torque sensor, possibly one from Bafang? (There are some 120mm "T9" torque sensors on aliexpress)
-Get rid of the cycle analyst and instead use my own microcontroller for torque sensing (I wish the CA code was open source)
-Integrate grins analogue style brake lever into the 3shul controller for variable regen braking
-Add a 5 or 7 speed freewheel to the QS 205 using round nuts if needed
-Add the largest possible chainring on the front, I want to pedal at 30mph!

The frame as it came from Fucare


Here is the headset, had to buy cups for it


Cups installed


Top head tube takes a ZS44/28.6, bottom takes a ZS55/40, I'm using an adapter for a non tapered fork.

 

[Chalo]

What is it with folks using fatbikes for fast e-bikes? Fatbikes are for crawling slowly through soft crud, and that's the only thing they're any good at. Using fat tires (like 3.5"+) on the street only reduces your speed, range, and handling qualities without giving you anything good in return (and it marks you as a n00b and/or a dingdong).

After an adult lifetime of getting stoked and impressed by larger and larger bike tires, I was quick to try fatties when that was feasible for me. Trying them cured me of my infatuation right away. They're depressingly slow, with terrible steering that only gets passable if you overinflate them to the point that they don't have any of the cush or flotation their size allows.

That's a disc braked bike. You can use 29 x 2.5" or 27.5 x 3" wheels and tires for about the same overall diameter as 26 x 4", and your bike won't suck as much if you do that.

If you must go with 26" fatties, at least give yourself 65mm rims so you can use real tires in the 2.2" to 3" range once you figure out how disappointing fatbike tires are.

 

[nicobie]

Nothing wrong with building a bike for looks. However please realize that Chalo is correct.

 

[jonpad01]

The reason for the fat bike frame is simply this, I want a 7 speed freewheel on a QS 205.

As for the tires, I have no comment because I have never used 4" fat tires. The plan is to try 4" tires first, but the rear rim that I am lacing to the motor will be 65mm so I can fit smaller sizes if I don't like them. The front is an 80mm rim because that's the only size I could find that comes as a complete wheel. I might consider building a front wheel at a later date.

The other reason I wanted wider tires is because I had a 1.95" wheel spin out from under me and put me on the ground last year, broke my elbow.

My use case is all terrain for the most part, dirt trails with steep climbs, but also city streets.