DIY ebike project advice

[Eugene12]

Hello,

After spending sometime reading and watching custom ebikes I decided to built one myself.

So my preferred specs are:

• - Able to go uphill on FSR and single track in Southern BC.
• - Pedal assist as I still want to workout and return back in an emergency.
• - A dirtbike design as I want to put bike bags when riding on FSR for camping.
• - Top speed is non essential, 30-40 km/h, no more. I'm concerned about torq and range in the first place. 30 km on motor and 60 with pedal assist would be more than enough for me.
• - Weight under 30 kg

I saw Surrons but they are only motor driven and not affordable for me. I even considered buying an old dirt bike, throw all internals. I think it'd be way heavier and too wide for pedalling. So I ended up researching builds with stealth bomber style EBB frame.

Like here https://www.aliexpress.com/item/1005005261877983.html

Usually people go with a hub motor but for off-road mid drive is better. Dirt bikes, EMTBs are all with mid drives. I found decent reviews about bafang 1000w mid motor

I'm curious if it fits that frame because I see no such projects. I'm also unsure if this motor powerful enough for my build as hub motors in bomber clone builds are usually 3000+ watts.

Any advice on parts/builds will be appreciated!

 

[Eugene12]

I'm also not sure about performance of hub motors in the mountains. DH/jumps are not for me but durability and ability to go uphill like 15% is the issue

 

[E-HP]

I saw Surrons but they are only motor driven and not affordable for me.

Don't keep your budget a secret.

 

[Adrian_]

Mid drive EEB frame has been done, I'm only aware of one thread but it required grinding down fins on the motor which is Bafang BBSHD to make it work, he's some pictures and build thread link: Enduro ebike frame documentation - Electricbike.com Ebike Forum

 

[calab]

A freewheeling hub like a MAC geared hub w/generic controller that has pas feature would be nice for southern bc.
If you do lots & lots of hills, long hills or steep hills, a mid drive has its benefits but lots of draw backs.
Who sells the MAC geared hub motors now, buy it from the source.
29'er wheels is easy going over bumps, which means if your not in it for speed get a motor winding that suits your speed requirements and remember the voltage plays a role.

 

[amberwolf]

If you are willing to put in some learning and experimentation time, you can use the motor simulator at ebikes.ca to determine the power and torque levels required for the job you need the system to do, and get a guesstimate of the Wh/mile requirements for your range as well. This will let you better choose an appropriate drive system including battery requirements.

The default options are setup for hubmotors but with some optional features you can enable, you can use it for middrives.

 

[Eugene12]

Thank you for the answers. That simulator looks really nice.