Frame mount for electric mid-drive?

[Jon Norstog]

To the list:

I built one electric bicycle this summer, for my wide, but have now got the bug.  I'd like to build a mid-drive, with the Shimano or Bosch engine.  Is there a source for the steel housing that mounts the drive unit? 

TIA your suggestions!

jn

"Thursday"

[Rick Klint]

bo...@saris.com
He has CNC and 3D versions for Bosch mid drives

[Brandon Ives]

Jon,

Dave Levy has made some for the Shimano 6001/7000/8000 series motor mount adaptors and posted them to one of the FB framebuilder groups. I assume you know him, but if not he’s in Portland (was Seattle yearrrrs ago) as Ti Cycles.

Best,

Brandon Ives

Springfield, MO

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[Jon Norstog]

Thanks, guys!  What I am thinking is more motorcycle than bicycle here ... BMX geometry, 26" wheels and under 50 pound total weight.

jn

[Rick Klint]

https://lunacycle.com/bafang-ultra-magnesium-motor-ebike-mid-drive

[Chris Blandford]

I’ve built a couple frames using the cabinets from Framebuilder Supply:

https://framebuildersupply.com/collections/electric-motor-mounts

Tony also sells a jig adapter—which I’ve seen but haven’t used. Looks perfect.

Here’s a 26” frame I made for my wife. The Steps system is amazing. No regrets.

-Chris

-
Chris Blandford
Blandfo...@gmail.com

[Jon Norstog]

Thanks, Chris.  Framebuilder Supply is an easy ride from my place!

jn

[Alex Wetmore]

Under 50lbs total weight and more motorcycle than bicycle is a hard combo.  The good BB motor systems weigh around 15lbs.  A minimal battery that will get decent runtime with decent power output will be a "10S5P" configuration which is about 36V and 15 amp hours with today's cells, and that'll weigh 6-7lbs.  Figure another pound of wiring and stuff, so you have to keep the rest of the bike under about 25lbs.  Production e-bikes rarely weigh under 50lbs and many are fairly low power.

I have two e-bikes, one was built to be light and I use it for commuting or getting around town when I don't want to be as sweaty.  It is under 40lbs with the e-bike system, but uses a lower power motor that only weighs 2kg (4.4lbs) and I use a 10S2P battery that weighs 1kg (2.2lbs).  That gets me 25ish mile range but I detune the motor to 300W (down from 500W) for lower power assist and more range.  The motor is a variation of the bafang MG311 that ebikes.ca sells.  I copied a lot of my spec from the Faraday (but used a lighter frame and better components), so you could ride one of those to see if it is for you.  

My other one is a cycletruck that I carry my son around on.  I halfway tried to keep it light, but it still ended up at over 50lbs with a 10S4P battery, kid seat installed, and large front basket.  Someday I'd like to make a lighter frame for it, the current one was the first frame that I ever "built" (it was modified from an already heavy Trek 800) and is way too stout and designed around heavier basket loads than I actually carry.

alex

---

From: frameb...@googlegroups.com <frameb...@googlegroups.com> on behalf of Jon Norstog <mutton...@gmail.com>
Sent: Friday, January 11, 2019 1:37:29 PM
To: Brandon Ives
Cc: frame builder list
Subject: Re: [Frame] Frame mount for electric mid-drive?

 

[Jon Norstog]

Oh yeah, I'm not going for highway speeds.  The legal speed limit is 20 MPH and that's good enough for dashing around town.  I'm thinking direct drive on a 26" BMX bike with a drive mounting plate instead of a BB.  Both Shimano and Bosch have pretty decent mid-drives in the 4 kilo range, the question being whether they are up to a direct drive operation.

Later on I might try to put together a 100-pound bike that could run at highway speeds.  Something like thaT you would have to license and insure just like it was a Hayabusa.

jn

[Alex Wetmore]

I didn't mean highway speeds, I meant with minimal human assist.

Are you looking to build something more like a scooter that has zero human assist?  I think it'll be challenging to do that in under 50lbs with a 20mph top speed and decent range (20-30 miles), but if you do please share the results.

alex

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From: Jon Norstog <mutton...@gmail.com>
Sent: Sunday, January 13, 2019 9:23:28 PM
To: Alex Wetmore
Cc: Brandon Ives; frame builder list

[Rick Klint]

What do you mean by direct drive?

[Chris Blandford]

I've gotten a few private emails asking about the ebike photo I posted, so figured I'd add a couple more notes & images here. Hope John or others down the road find this helpful! Take this for what its worth, which is probably very little; I'm a hack hobbyist w/ little knowledge about ebikes in general. These are just my observations from building a couple of these frames.

The ebike I posted previously was built around the Shimano STEPS E6000 mid-drive system. I've built two and assembled three of these and ridden them pretty extensively. I've also ridden a couple other hub-drive ebikes, but don't have any mechanical experience with those. My conclusion is that the STEPS system (and likely the Bosch mid-drive system, too) is WAY MORE "bicycle-like" than any of the other hub-drive motors I've tried. The STEPS units I've used do not have a throttle of any kind. The pedal-assist, however, is truly amazing - natural... not jerky or artificial or motorized whatsoever. These things have honestly changed the way I look at riding bicycles for transportation, especially here in hilly SW Portland.

Here are a bunch of photos of my first, unpainted version: http://theblandbicycle.com/projects/the-noise/

(I also own a STEPS Metrofiets cargo bike that I regularly load up with child, groceries, etc.; it doesn't skip a beat. To borrow from my (actual) motorcycle experience, the Steps motor definitely feels more "torque-y" than "horsepower-y", if that makes sense.)

John - I'm not sure what a direct-drive (I assume you just mean singlespeed?) STEPS bike would ride like... my instinct says that you'd be coasting a ton regardless of the gear you chose. A 26" BMX-style e-bike sounds sweet, but you might want to test ride a STEPS bike before committing... it might not be exactly right for what you're going for.

Building the frames and assembling the things is way more straightforward than I imagined, though.

I held the motor cabinet in place with a jig adapter I made from a regular BB and some plate. Just like a Pinion mount. Like I mentioned, Framebuilder Supply now sells something similar. The other odd thing is the battery mounts... They use a regular M5 boss, but the battery needs to sit up at least a couple mm's from whatever tube it's mounted to. I raised mine up off the down-tube with a thick reinforcement thingy. Oh, and the speed sensor mount: another M5 boss sunk into the inside of the chainstay. That was my solution, anyway. I've seen other hardware-store clamp-on solutions.

Assembly is very straightforward. Plug everything in--no instructions provided or needed--and it just fires right up and works. My Metrofiets has hardwired lighting (on/off switch is on the STEPS control unit)... that works out of the box, too. Super simple and slick.

I've never weighed any bicycle, let alone one of these beasts, but my bicep-curl-kinda-feels-like test tells me... right around 50 lbs for the one I had painted. It doesn't matter, though. My Metrofiets is probably pushing 100lbs. The only time I notice it is when I'm locking it to a rack and have to move it sideways-ish fully loaded.

Anyway, I hope that helps somebody! If you're in doubt: DO IT. And don't knock it til you've tried it... I'm as "use your own two legs" as anybody, but I couldn't go back to not having at least one ebike in the garage.

-Chris

[Alex Wetmore]

The ebike I posted previously was built around the Shimano STEPS E6000 mid-drive system. I've built two and assembled three of these and ridden them pretty extensively. I've also ridden a couple other hub-drive ebikes, but don't have any mechanical experience with those. My conclusion is that the STEPS system (and likely the Bosch mid-drive system, too) is WAY MORE "bicycle-like" than any of the other hub-drive motors I've tried. The STEPS units I've used do not have a throttle of any kind. The pedal-assist, however, is truly amazing - natural... not jerky or artificial or motorized whatsoever. These things have honestly changed the way I look at riding bicycles for transportation, especially here in hilly SW Portland.

Hub drive systems can also work this way (test ride a Faraday, or if you are in Seattle come ride one of my bikes).  The motor location isn't key to the Bosch and STEPS systems, the torque sensing system is key.  Torque sensing bottom brackets are out there, they aren't common on hub motor systems because they make the retrofit more complicated and cost money, but they allow for throttle-less systems.  I agree that the right systems feel totally natural and like a bike, just easier.

I really like the Bosch system and it rides great (I've never ridden the STEPS system).  For a human power first system I still prefer a hub motor because they feel a lot better under human power alone.  The Bosch runs the cranks through a planetary gear system that doesn't feel that efficient.

I agree that weight doesn't matter that much, unless you have stairs between your bike storage and the street.  I do and wish I didn't.  I think that there is good reason for a longtail electrified cargo bike to weigh around 60-70lbs, anything lighter is probably a compromise in carrying capacity, range, or both.  I want a bike to weigh under 50lbs If I need to carry a bike up or down stairs every time that I use it.

alex

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From: frameb...@googlegroups.com <frameb...@googlegroups.com> on behalf of Chris Blandford <blandfo...@gmail.com>
Sent: Monday, January 14, 2019 11:33:38 AM
To: Framebuilders
Subject: [Frame] Re: Frame mount for electric mid-drive?

 

[Chris Blandford]

Cool! Thanks for the info. All makes sense, especially about the weight. I wouldn't want to shoulder any of the ebikes I've ridden!

-Chris

[T]

Finally, something I actually know a bit about    ;-}
    About 19 years ago, I actually helped prototype the mid-drive used by eco-speed, who has the patent on mid-drives.
Like many things, the production models are heavier than a decent custom build.  Business issues dictate this.
    I built my sister an E-bike about 8 years ago, designed to more be sturdy than light, and it weighs 35lbs plus whatever battery you put on it.  Built onto a specialized rock-hopper, a medium-light frame in it's day.   I also put a system onto my kokoPedli unFolding bike, the folding bike + motor/controller weighed in at about 29/30lbs, plus whatever battery I put on it.
   The couple of things to think about are mostly related to knowing your needs/desires.  This will probably change over the time-span of getting used to E-bikes.
    First, I HATE torque sensing bottom brackets!   I'll tell you why.  For me, I want the E-assist when  > I <  want it, not all the time, and very much, the time I most want it is when  I DO NOT HAVE THE "UMPH" TO PEDAL !   So, why get one that senses torque?  I would want one that sensed when my torque was getting weaker, but still need to keep moving   =)
    A thumb throttle is the only rational way to go in my world, my needs.   
I do realize that some people have other desires which fit well with sensors, but, after almost 20 years of occasional E-bike use, I'll take a throttle and less gizmos that can go wrong (or over-control my life).

So, what do "my" systems look like?   A basic motor, motor-mount aluminum plate the bolts to aluminum angle that bolts to standard water-bottle bosses already on many frames.
   Connect this to a tandem IPS crank-set, a controller and battery and your good to go.

Actually, hub-motors are a fine way to go to, simpler...   but not as efficient therefore not as far on a charge.

And, I think E-bikes are a great thing for many reasons, my next E-build will be a mid-weight steel "mtn.bike" frame that will have a fairly strong system because it will have an easy-on/easy-off long-tail conversion (of my design) that will turn it into a cargo bike...   and a trailer hitch for those really big-heavy loads.      =)     I expect it to weigh in at about 34 to 36 pounds plus battery in it's minimal basic bike configuration.
     Thomas
kokoPedli.com

[johannes richter]

Excuse my probably really basic/stupid/laymen's questions (I am mainly
an interested reader on this list)

Is this welded (I guess not?) or soldered (I guess so? brass soldered?)
or something else?
It looks beautiful to my laymens eyes : )

Thanks, best regards,

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