Mauimart - Mid-mount Hub Build

[mauimart]

I finally got around to starting my next build. It's a 2004 Specialized Big Hit which will be powered via a two-speed mid mounted hub motor. The plan is to attach everything using a bolt-on strategy--no welding or punching holes into the original roller. Initial setup will be as follows:

- #35 drive train with a direct drive ratio between 1.5:1 and 2:1 (future plans for belt drive - PolyChain)
- 72V to 100V, up to 2kWh battery, possibly HK lipo or Enerdel
- controller unknown, possibly a home build down the road
- will maintain the 2-speed capability with possible future plans to mod it for single speed once I have some actual motor performance data

I have begun with some renderings and mock-up parts cut from wood.

 

[litespeed]

Great job on the mock up wood pieces. Looks like a great idea.

Tom

 

[etard]

Great concept man! This looks like a really well balanced build.

Are you using a laser to cut those wood mock ups, or do you really love drilling holes? :lol:

That's beautiful frame, I can see why you don't want to hack into it...

 

[mauimart]

Great concept man! This looks like a really well balanced build.

Are you using a laser to cut those wood mock ups, or do you really love drilling holes? :lol:

That's beautiful frame, I can see why you don't want to hack into it...

Yes, the wood parts were cut on a laser. I forgot to mention that I have access to some pretty incredible machine tools--waterjet, CNC mill, CNC lathe, laser cutter, ironworker, and 3D printers. Once the design has been solidified I will cut the motor mount brackets out of 0.25" aluminum on the waterjet.

 

[spinningmagnets]

Is that one of John in CRs "mini monsters"? Either way, it should be a climbing beast with that much copper...

 

[Whiplash]

Wow. Super clean mockup! Anybody have anything to say about those big cells? Look pretty impressive!

 

[whereswally606]

Very nice. Looking at that big hit makes me think I could do the very same with a norco savage frame I have reserved for my future middrive design. Subscribed

 

[mauimart]

Is that one of John in CRs "mini monsters"? Either way, it should be a climbing beast with that much copper...

That is indeed the motor. I am looking for it to do around 6kW continuous with bursts up to 10 kW.

 

[hydro-one]

NICE! i cant wait to see it in action!! i want to copy this!!!

 

[pkirkll]

ohhh, i like it!!!

If it could be made out of wood for good .........i wood --lol---be happy,,, no cnc or goodies..

i have a 1000w Golden i may try to take from the rear to middrive on a Novara-----(may be too big]---the monster is nice!!!!

i really want to make something like an e-tote goat or Rokon..... for the high desert

 

[John in CR]

Looking good Mauimart. I could never build a mockup that nice, because I wouldn't be able to resist the temptation to ride it.

With your skills and tools I'd consider mocking up a swingarm to fit the motor before making a final decision. If you're shooting for that kind of power having the motor torque anchored from outside of the swingarm, I believe the motor torque pulling on the chain will have large effects on the rear suspension. You'll probably need the longer wheelbase anyway.

 

[madin88]

nice engineered parts!

how heavy is that motor and what kv?

I would mill the motor round to not get hurt if someone get in touch with the spinning housing.

 

[waynebergman]

The motor will not spin. The axle will spin.

 

[dbaker]

note the wires coming out of the shaft. Motor hub will spin.

 

[waynebergman]

I guess my mind is still thinking about my mac conversion where the axle does spin. Sorry about that.

 

[jateureka]

Any more updates on this build?