DD Motor

Electric Motors and Controllers
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hillzofvalp   1 MW

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DD Motor

Post by hillzofvalp » Jul 25 2021 12:57am

...abandoning
Last edited by hillzofvalp on Aug 29 2021 7:44pm, edited 5 times in total.

mxlemming   1 kW

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Re: Interested in developing a DD hub motor

Post by mxlemming » Jul 25 2021 1:24am

3kW+ with 0.2 or 0.25 laminations
135/142mm preferably through axle
Proper splined cassette fitting for 10/11 speed cassette
Large diameter torque arm mounts
Disc mounts

I.e. a high power hub motor that actually fits to mountain bikes without masses of frigging. I don't think there is one yet.
Why can't everything be easy...

Vbruun   100 W

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Re: Interested in developing a DD hub motor

Post by Vbruun » Jul 25 2021 11:55am

I think a motor similar to bionx D series would be nice. What I mean by that is large diameter, light weight hubmotor that can put out a Lot of power.
There are lots of powerful and heavy DD hubs.

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Re: Interested in developing a DD hub motor

Post by HrKlev » Jul 25 2021 12:09pm

A DD rear hub for through axle with proper torque arms does not exist as far as I know. That would be nice for people building semi-fast FS bikes for onroad use with a modern frame.
Hubdrive as middrive, with torque sensing EMTB build: viewtopic.php?f=6&t=107622

6x6 conversion: viewtopic.php?f=34&t=109567

markz   100 GW

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Re: Interested in developing a DD hub motor

Post by markz » Jul 25 2021 2:01pm

This is a good read on lam's, losses, drag and BionX and further down the plastic shell it used.
viewtopic.php?f=30&t=90037&p=1445572&hi ... x#p1445084
viewtopic.php?f=30&t=90037&p=1445572&hi ... x#p1445572

In general for me on hub motors its all about cost vs the power I require for hills at casual speeds.

For the performance oriented, efficiency gamers, and the power thirsty then cost is probably not a factor.

So it comes down to what market do you want to sell to hillzofvalp?

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hillzofvalp   1 MW

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Re: Interested in developing a DD hub motor

Post by hillzofvalp » Jul 25 2021 2:02pm

Okay. Thanks for input everyone. I just want to make an awesome motor (probably 2-3x cost of most comparable motors, but you'd be paying premium for innovation and aesthetics) and test it in the wild with enthusiasts before looking very much further. I could imagine myself selling these through an agreement with GRIN or someone else eventually, but that's probably at least a few years into the project. I would like to see a few thousand miles accrue on a dozen prototypes before any serious consideration in mass production.

Do you think that I could post a gofundme and get say $15k from people on here to build a prototype?

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nicobie   1 GW

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Re: Interested in developing a DD hub motor

Post by nicobie » Jul 25 2021 2:23pm

Good luck with the motor project. However personally, I would not like this forum affiliated with any kickstarter/gofundme scheme. :lowbatt:
Ask for it by name.

my eTownie build thread: http://endless-sphere.com/forums/viewto ... =6&t=23701
Magazine article https://www.electricbike.com/nicks-etownie/

Grantmac   10 kW

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Re: Interested in developing a DD hub motor

Post by Grantmac » Jul 25 2021 3:49pm

The problem with DD motors is weight and low end torque. Fix that and they become relevant.

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Chalo   100 GW

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Re: Interested in developing a DD hub motor

Post by Chalo » Jul 25 2021 4:15pm

mxlemming wrote:
Jul 25 2021 1:24am
3kW+ with 0.2 or 0.25 laminations
135/142mm preferably through axle
Proper splined cassette fitting for 10/11 speed cassette
Large diameter torque arm mounts
Disc mounts

I.e. a high power hub motor that actually fits to mountain bikes without masses of frigging. I don't think there is one yet.
"Masses of frigging" is what happened to MTBs in the last 20 years. Now we all live with the drawbacks as well as the benefits.

The more carbony, curvy, and non-truss-like MTBs become, the less capable they are to handle superhuman power levels.

I really doubt that 135mm spacing would allow room for a 10/11/12/13 speed cassette on one side, clearance for a disc caliper on the other, plus a stator wide enough to rate 3kW.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

mxlemming   1 kW

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Re: Interested in developing a DD hub motor

Post by mxlemming » Jul 25 2021 7:19pm

Chalo wrote:
Jul 25 2021 4:15pm
mxlemming wrote:
Jul 25 2021 1:24am
3kW+ with 0.2 or 0.25 laminations
135/142mm preferably through axle
Proper splined cassette fitting for 10/11 speed cassette
Large diameter torque arm mounts
Disc mounts

I.e. a high power hub motor that actually fits to mountain bikes without masses of frigging. I don't think there is one yet.
"Masses of frigging" is what happened to MTBs in the last 20 years. Now we all live with the drawbacks as well as the benefits.

The more carbony, curvy, and non-truss-like MTBs become, the less capable they are to handle superhuman power levels.

I really doubt that 135mm spacing would allow room for a 10/11/12/13 speed cassette on one side, clearance for a disc caliper on the other, plus a stator wide enough to rate 3kW.
I just want an mxus3k turbo that takes a through axle to fit... basically every downhill bike frame produced since 2005.

The xf40c has a standard cassette with tons of wasted space and the 3k turbo goes 142mm (which also goes into 135mm if you apply enthusiasm).

So i don't think this is far off.

Downhill bikes are feckin tough. The disc mounts see far higher forces than a motor can create. Mine have shrugged off landing an 8 foot drop to flat with the rear wheel locked. I think with a sensible torque arm most mountain bikes will take it.


https://m.youtube.com/watch?v=n1JONofyurA
The carbon vs aluminum myth was put to bed a long time ago.
Why can't everything be easy...

markz   100 GW

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Re: Interested in developing a DD hub motor

Post by markz » Jul 25 2021 10:20pm

How about an axle that can accommodate big ass phase wires with better wire routing to the outside.
Last edited by markz on Jul 25 2021 11:29pm, edited 2 times in total.

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Chalo   100 GW

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Re: Interested in developing a DD hub motor

Post by Chalo » Jul 25 2021 10:43pm

mxlemming wrote:
Jul 25 2021 7:19pm
The carbon vs aluminum myth was put to bed a long time ago.
Heat treated aluminum is more or less isotropic. It has the same strength in every direction along its surface.

Carbon is anisotropic. It only has strength in the directions it was designed and constructed to have strength in. So when you exert forces on it that it wasn't specifically designed to resist, you do so without understanding whether it's strong enough to do that.

Here's a picture of a carbon bike that stabbed a wheel reflector right through its chainstay:

Image

That bike was plenty strong for doing what its designers had in mind, but not strong enough to resist a plastic wheel reflector. Are you willing to wager that your bike's designers were thinking about what you intend to do with your bike? Because if not, you'd probably be better off with an isotropic frame material.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

JackFlorey   100 kW

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Re: Interested in developing a DD hub motor

Post by JackFlorey » Jul 25 2021 10:48pm

markz wrote:
Jul 25 2021 10:20pm
How about an axle that can accommodate big ass phase wires with better wire routing to the outside.
I would think you would NOT want wiring routed through the axle. It's more prone to damage that way.

markz   100 GW

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Re: Interested in developing a DD hub motor

Post by markz » Jul 25 2021 11:30pm

markz wrote:
Jul 25 2021 10:20pm
with better wire routing to the outside.
Screenshot 2021-07-25 223208.png
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mxlemming   1 kW

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Re: Interested in developing a DD hub motor

Post by mxlemming » Jul 26 2021 2:13am

Chalo wrote:
Jul 25 2021 10:43pm
That bike was plenty strong for doing what its designers had in mind, but not strong enough to resist a plastic wheel reflector. Are you willing to wager that your bike's designers were thinking about what you intend to do with your bike? Because if not, you'd probably be better off with an isotropic frame material.
I doubt they thought about motors, but
1) they did think about disc brakes which are basically the same force and
2) I'll wager that that pic is not as it seems. Someone's hammered that reflector through it, using a chisel or screwdriver to make the hole, it's photoshopped or maybe (unlikely) there's a serious carbon layup error resulting in no carbon atall in that area.
3) that's the flimsiest bike imaginable, from 12 years ago
4) check the "smash it against a concrete block"test in there video i posted.

How about this new hub motor has an aluminum axle. Not sure how much the steel axles weigh but I bet you could save a load of weight.
Why can't everything be easy...

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hillzofvalp   1 MW

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Re: Interested in developing a DD hub motor

Post by hillzofvalp » Jul 26 2021 3:12pm

I'd probably design it to work on 142 only. Does anyone have a CAD model of a 142 frame.. I rather design something that works really well on a small fraction of available frames (but maybe the best of the bunch) than something that is so-so on more variety of frames.

How about designing it to bolt directly to the caliper mount? Without caliper in the rear there is more space for motor.. I don't see a real need for rear caliper with regen. I guess redundancy.. But you can run dual front calipers for redundancy. Idk, this might be a crazy idea

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Chalo   100 GW

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Re: Interested in developing a DD hub motor

Post by Chalo » Jul 26 2021 3:26pm

mxlemming wrote:
Jul 26 2021 2:13am
2) I'll wager that that pic is not as it seems. Someone's hammered that reflector through it, using a chisel or screwdriver to make the hole, it's photoshopped or maybe (unlikely) there's a serious carbon layup error resulting in no carbon atall in that area.
Nope.

http://pardo.net/bike/pic/fail-001/FAIL-116.html

I was still participating in rec.bicycles.tech when Andy Muzi of Yellow Jersey showed it to us.

Anyway, it's still a problem with today's bikes including MTBs. That's why there's such a thing as "shelter tape" to keep little stone chips from destroying your carbon frame. One of my coworkers wrote off his Yeti MTB's frame because something hit his frame right in the 1/4" gap between pieces of protective tape. Whatever caused it was something he didn't even notice at the time.

I'll reiterate: Carbon fiber reinforced plastics can be very strong at resisting anticipated forces, but extremely weak at resisting unanticipated forces. In the direction of the fibers, CFRP is a supermaterial. Across the direction of the fibers it's just thin plastic.

So did your frame's designer take into account the forces that are peculiar to e-bikes? How many extra layers of expensive material were used so it would be overbuilt enough to cope with unanticipated loads?
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

mxlemming   1 kW

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Re: Interested in developing a DD hub motor

Post by mxlemming » Jul 27 2021 1:51am

Chalo wrote:
Jul 26 2021 3:26pm
mxlemming wrote:
Jul 26 2021 2:13am
2) I'll wager that that pic is not as it seems. Someone's hammered that reflector through it, using a chisel or screwdriver to make the hole, it's photoshopped or maybe (unlikely) there's a serious carbon layup error resulting in no carbon atall in that area.
Nope.

http://pardo.net/bike/pic/fail-001/FAIL-116.html

I was still participating in rec.bicycles.tech when Andy Muzi of Yellow Jersey showed it to us.
They don't even come with reflectors... i cannot find a single pic with reflectors on a trek madone. The model pictured had the doubled up blade spokes you couldn't even put reflectors on.

Further, the mechanics of that pic don't add up. The reflector is now a clear inch away from the spokes so what was driving it through the other side of the carbon tube? I get that the length might have been enough for the entry, but the exit? At that angle?

Did you actually see this? Did Andy Muzi actually see this? If so, does he have an equally big vendetta against carbon?
hillzofvalp wrote:
Jul 26 2021 3:12pm
How about designing it to bolt directly to the caliper mount? Without caliper in the rear there is more space for motor.. I don't see a real need for rear caliper with regen. I guess redundancy.. But you can run dual front calipers for redundancy. Idk, this might be a crazy idea
I run no rear brake and regen on my ebike. I'm not entirely convinced by it. The controller occasionally trips and then i have no brake. I'd err on the side of making the disc Mount available, though you could double using it up?
Why can't everything be easy...

markz   100 GW

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Re: Interested in developing a DD hub motor

Post by markz » Jul 27 2021 3:07am

Actually they do come with a reflector or light mount bracket, but for the visibility from the rear.
If you want reflectors where people can see you from the side then you need to find them and install them.
Like these people done, sure they are different reflectors then the one that damaged the bike. Of course theres other stories online in forums about a crank bolt piercing the frame and another story of a crank gear.

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Chalo   100 GW

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Re: Interested in developing a DD hub motor

Post by Chalo » Jul 27 2021 11:09am

mxlemming wrote:
Jul 27 2021 1:51am
They don't even come with reflectors... i cannot find a single pic with reflectors on a trek madone. The model pictured had the doubled up blade spokes you couldn't even put reflectors on.
If you'd worked in a bike shop, you'd know that every bike sold complete in the USA comes with front, rear, wheel, and pedal reflectors. It's a CPSC requirement. There's no requirement that the retailer install them, but some always do it as due diligence. Most retailers don't install reflectors on purely sporting bikes.

Stuff happens. It happens more easily when your bike is made of thin plastic.

I had a 79 year old customer come in last year after a whoopsie on the bike path on his Pinarello Dogma. I trued up his wheel and sent him on his way, but an inspection by his bike's dealer discovered that his frame, fork, and one wheel were all damaged beyond economical repair. All of the damage would have resulted in only cosmetic scratches on metal parts. (I got to check them out when disassembling the bike and packing the parts for shipment.)
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: Interested in developing a DD hub motor

Post by qwerkus » Jul 31 2021 1:02pm

hillzofvalp wrote:
Jul 25 2021 12:57am
Hello,

It's been a while since I've been on this forum. Since then I designed a couple halbach outrunners and tooling to create them. I'm interested in applying my learnings and creating a nice halbach offering for ebikes.

What would you say are the specs of an ebike DD hub motor that is missing from the market?

Also, what would you say are the top 3 motors out right now, what are their specs, and do you have access to their magnetic geometries?
I'd vote in favour of a dd hub with power levels similar to the RH212 which is already plenty, maybe a bit of weight optimization, but definitely the ability to integrate shimano internal geared hubs - similar to the tcdm. No more derailleur and more thermal mass to absorb peak power. Should ppl want it, they could still bolt out the IGH and swap it for a splined freehub unit though I would not see the point. The whole Idea of a DD hub is a maintenance free robust setup, which is exactly the strength of IGHs.

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Re: Interested in developing a DD hub motor

Post by The Toecutter » Aug 01 2021 11:52am

I think a synchronous reluctance hub motor of about 5 lbs would be perfect for an ebike. You'd have no cogging torque and thus no penalty when operating purely under pedal power, the motor would have efficiency so high that you'd be able to make massive amounts of peak power if desired(possibly 15-20 kW peak for 5-10 seconds at a time) in such a small package while still being able to do 2+ kW continuous, and the mass would be almost as if there was nothing there versus a traditional 15-20 lb hub motor when it comes to acceleration.

You'd probably want it to be able to fit in dropouts as narrow as 135 mm, with compatibility for commonly available gearing types(perhaps 11 speed cassettes?).
Custom electric velomobile, 1500W: viewtopic.php?f=6&t=110298

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hillzofvalp   1 MW

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Re: Interested in developing a DD hub motor

Post by hillzofvalp » Aug 21 2021 7:32pm

Would anyone on here agree to throw $50 to a research project? Two nice meals, or a single meal with your wife who you don't like eating with anyways. 250-500 of those people on here?

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The Toecutter   10 kW

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Re: Interested in developing a DD hub motor

Post by The Toecutter » Aug 21 2021 8:22pm

I'm willing if others can get on board with the idea.
Custom electric velomobile, 1500W: viewtopic.php?f=6&t=110298

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Brocolli-Awesome Motor (BAM) Survey for Everyone

Post by hillzofvalp » Aug 21 2021 11:21pm

Click here for the BAM Preliminary Survey, It only takes 1-2 minutes, and everyone here is encouraged to fill it out. I won't contact you via your email unless perhaps you ticked a box that says you're interested in possibly eventually donating: https://forms.gle/CNHtYGAx734SCs8i8.

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