My first ebike build: custom-built KMX-based electric velomobile

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The Toecutter   100 kW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Dec 30 2021 3:09pm

Triketech wrote:
Dec 30 2021 10:41am

The majority of my riding is 15-25 MPH, although plenty of long steep elevation and 1800 watts and that may be occasionally exceeded, so my current rig is "good enough for now". :)
Do you have a link to more information on it?

My front track is 39" wide, which helps stability tremendously versus the typical 31-33" track typical of what is on the market. I also have 18 lbs of battery mounted underneath the front boom and the rider position as far forward as possible and the seat as far reclined as possible given the KMX frame's parameters and the current use of a 26" wheel. This rear suspension and a 20" rear wheel should allow a steeper recline angle due to increased clearance.

As long as the rear wheel is kept from potholes, even unsuspended with a 17 lb hub motor, cruising at 45 mph is deceptively stable. I say deceptively stable, because while it rides smooth and feels safe and is very controllable, my brakes are not yet up to the task! I suspect that with hydraulic disk brakes and full suspension, this platform may be stable at highway speeds and capable of consistent stopping performance from such. It will need a lot of changes to be mechanically safe at highway speeds, however, and I could forget about significant safety in a collision at said speeds.
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by Triketech » Dec 31 2021 10:03am

The Toecutter wrote:
Dec 30 2021 3:09pm

Do you have a link to more information on it?
This is one of them from 5 years ago; it's been updated with a Wolf Battery and relocation of components since. At 5000 miles did a motor teardown. Replaced clutch & gears since I had spares but they were still had at least another 5000 miles left on them.

http://www.triketech.com/Drivetrain/Pow ... AC-V2.html

39" vs 31" front track will definitely improve lateral stability and that helps reduce the rear "skid steer" from jolts, although adding the hub motor tends to toss the rear much harder when it bounces. It's not so hard to control when it's anticipated, its when its not anticipated when you leave a loaf in the shorts.....

When speeds begin to exceed 30 MPH a good term to be familiar with is "Crushable Substructure". Those would be a trike rider's legs. Were you aware that an 10 MPH collision with a concrete wall will is a leg busting experience? My wife learned that the hard way and she's rather athletic for her age. I bring that up because the cause of her Expedition crash was from the rear wheel hitting a 2" rock that tossed her sideways enough to direct her off the trail into shallow ditch with a concrete embankment. No damage to trike; 42 pieces of steel to reconstruct Fibula.

Apologies for the safety point; I'm still a bit sensitive to loosing John Abbey (Airmoose). From a safety standpoint, I feel a lot safer driving a shifterkart at triple digits than on any pedal powered machine on roads with speed limits in excess of 25 MPH. That said, I don't always obey safety dictates.. :)

Frankly I've been on the fence over custom building an E-trike frame-up. We seem to keep adding unit stuff to trikes without evaluating the system so it's always ending up as a kluge. Even from the OEM's, but keep in mind, these are the folks who mount hand controls upside-down to look better in the showroom. It helps to have a vehicle design and fab background too.

• Drivetrain on a trike has a long path and needs a wide gear ratio to pedal at 2 wheel fall over speeds
• 20" rear tires eliminate long cage derailleurs
• Once a rider has 300W+ of boost they don't care much about a few watts of drivetrain loss
• Current Mid Drives are the most efficient but clobber the drivetrain with ratio limits and rapid wear
• Hubmotors add excess unsprung weight
• Virtually no trikes on the market with optimized front suspension

Several years back I began with a "clean sheet of SolidWorks paper" and developed little different approach with some of those 6 points in mind. Concurrently I've been developing the "Desert Scorpion" a moniker I gave my FS26.

Which is why I'm stuck on the fence; the FS26 is like a 100 watt light bulb burning at 75 watts when only 60 watts is needed. It's that need to go all the way to bright thats driven my career.....

Before I sold my business I had the tools to fab including CNC, 1500W laser, TIG/MIG, PCB development etc. Besides at my age my TIG skills rely more on feel than sight if you know what I mean. :) So it would take some collaboration with an OEM; and guess what? Goal accomplished. Thats all I can say for now.

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Dec 31 2021 11:31am

Triketech wrote:
Dec 31 2021 10:03am

This is one of them from 5 years ago; it's been updated with a Wolf Battery and relocation of components since. At 5000 miles did a motor teardown. Replaced clutch & gears since I had spares but they were still had at least another 5000 miles left on them.

http://www.triketech.com/Drivetrain/Pow ... AC-V2.html
I've read this page before, and it was very informative. Your site helped guide some of my decisions 6 years ago when I was restoring an old Thunderbolt trike.
39" vs 31" front track will definitely improve lateral stability and that helps reduce the rear "skid steer" from jolts, although adding the hub motor tends to toss the rear much harder when it bounces. It's not so hard to control when it's anticipated, its when its not anticipated when you leave a loaf in the shorts.....
The worst I've experienced is a pothole on Kingshighway Blvd launching my rear wheel into the air at 40 mph in traffic. I still retained control of the trike by waiting for the wheel to contact the ground and regain traction before correcting the steering. It was scary, but not enough to "leave a loaf in the shorts". I eat like a 300 lb lardass and burn through all the calories(close to 4,000 a day, mostly from nuts and produce, about 15 lbs of food in a day in all), keeping me thin, so the lower GI tract is always primed and ready with pounds of material and I'm having to find a restroom every few hours to assure nothing is ever left "in the shorts". Many a poor public toilet has been clogged as a result, and that would be a massive disasster if such a monstrosity was inadvertently deposited in my pants while pedaling, nor certain the pants would contain it. True desperation is when you will waste no time to sit in a doorless stall or even a filthy un-partitioned seatless steel prison-style toilet at a park, in view of other people in the restroom. Still greatly preferable to messing one's pants with a massive solid loaf while pedaling. Sorry for the graphic description, but when you eat like a horse and exercise enough not to get fat, it's unavoidable, and I mention this because NEVER has a close call on my trike resulted in a close call down below. It's THAT stable. I don't feel at risk from my own actions while riding it. Hoping the rear suspension improves the stability over those sorts of rough roads though. It would be nice to greatly reduce any jostling of my insides during those times where it feels like I have a bowling ball or a brick sloshing about in them, because that is not at all a pleasant feeling. :lol:
When speeds begin to exceed 30 MPH a good term to be familiar with is "Crushable Substructure". Those would be a trike rider's legs.
My nose piece would be the first thing to crumple, albeit at the speeds I ride, its effects would be insignificant at best. I ride a fun little deathtrap.
Were you aware that an 10 MPH collision with a concrete wall will is a leg busting experience?
Yes. I studied physics a bit during school as an electrical engineer and in my own time on the side, and impulse is no joke.
Apologies for the safety point; I'm still a bit sensitive to loosing John Abbey (Airmoose). From a safety standpoint, I feel a lot safer driving a shifterkart at triple digits than on any pedal powered machine on roads with speed limits in excess of 25 MPH. That said, I don't always obey safety dictates.. :)
John died doing what he loved. There are worse ways to go. He was a valuable source of knowledge on velomobiles and I miss his input. I ride with idiots in greatly more massive vehicles sharing the road all the time, and unfortunately, have no means to prevent or isolate myself from their idiocy other than to not ride. And this thing is my transportation.
Frankly I've been on the fence over custom building an E-trike frame-up. We seem to keep adding unit stuff to trikes without evaluating the system so it's always ending up as a kluge. Even from the OEM's, but keep in mind, these are the folks who mount hand controls upside-down to look better in the showroom. It helps to have a vehicle design and fab background too.

• Drivetrain on a trike has a long path and needs a wide gear ratio to pedal at 2 wheel fall over speeds
• 20" rear tires eliminate long cage derailleurs
• Once a rider has 300W+ of boost they don't care much about a few watts of drivetrain loss
• Current Mid Drives are the most efficient but clobber the drivetrain with ratio limits and rapid wear
• Hubmotors add excess unsprung weight
• Virtually no trikes on the market with optimized front suspension
On the first point, I'm heavily considering a jackshaft kit with two or three speeds acting as an intermediate gear selection, and having two chains. I wanted to buy a Schlumpf HS Triple, but I wouldn't be able to use my Sempu torque-sensing bottom bracket, and no one seems to make a torque sensor that isn't a bottom bracket torque sensor. Further, the Schlumpf HS is limited by its BCD, so I'd have to go with a 38/4X/56T chainring setup, which would make my low gearing barely adequate even with a 20.5" rear wheel diameter(Mitas MC2 16x2.25" tire), which would mean 4.1 mph @ 60 rpm in my lowest low gear. The Schlumpf is an easier solution, except for the fact that there is no torque sensor available that would allow me to retain torque sensing PAS and use the wide gearing it offers, so the other outcome is that I have to make my own torque sensor, when my limited time could be spent perfecting the aerodynamics instead, or settle for a cadence sensing PAS which won't give me the kind of workout I'm after.

Regarding the long-cage rear derailleurs and clearance, that is something I am concerned about. I haven't had a chance to install the 20" rear wheel motor and see how much clearance I have. This lack of a wide rear range is not a major issue if I have some kind of 3rd gearing system to keep the overall range to my liking. I'm aiming for at least 1200% gearing range, and require nothing less for my application. I'd prefer around 1500%. My motor limits me to a 7-speed system however, due to the 135mm dropout width. There is a possibility of adding a 4th gear non my front chainrings as well. This is not an easy goal given my design requirements.

300W is enough if you're on flat terrain. I ride with 250W quite often. It is inadequate for many of the hills where I live, but on flat ground, it is more than enough. If I pedal with moderate effort, 250W is enough to get me to roughly 35 mph on the flat, but I'm pedaling with another 250W to do it, and this modest amount of power allows for my legs to do the accelerating up to cruising speed @ 600W+. On hills, this is obviously not tenable due to the length of time required and I tend to put it in the 750W or even 2500W settings and still pedal hard. I need to be able to keep traffic speeds to not get crushed. Before motorizing it, automobile drivers doing 35+ mph have deliberately ran me off the road while I was slowly climbing steep grades at < 10 mph, and it is only through dumb luck that I didn't crash or get injured.

I don't consider mid drives a solution for me. Their negatives defeat the design philosophy I have in mind. I like simplicity of maintenance, longevity of components, cheap build/operating cost, and repairability with readily available parts.

A lighter hub motor build with quality design and components, perhaps a high-efficiency non-PMDC design type with no cogging losses, to allow Leafbike levels of power, at half the weight or less, for me would be ideal. No one makes it for hobbyists at this time, even though many companies have demonstrated prototypes. AMZ made a geared hub motor of 7 lbs that could do 50 horsepower peak.

I'm very pleased with adam333's suspension design for the KMX. It's probably as close to optimized for this particular trike as is possible.
Which is why I'm stuck on the fence; the FS26 is like a 100 watt light bulb burning at 75 watts when only 60 watts is needed. It's that need to go all the way to bright thats driven my career.....
I know the feeling. I have 2500W available in a vehicle that can hit 45 mph with about 750W and hard pedaling, and currently only top out around 45 mph. And I have a Milan SL velomobile, that completely unmotorized, I can almost hit 50 mph in. My unmotorized one is actually FASTER than my motorized one in a flat ground sprint, and can keep about the same rolling average if I put the motorized one to 350W of assist. I'm all for combining the strengths of each into a unique vehicle, and then dumping car-like levels of power into it for the application of hauling ass, hooning about the neighborhood, and overall general hooliganism.
Goal accomplished. Thats all I can say for now.
It will be interesting when you can tell me more.
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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The Toecutter   100 kW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Jan 04 2022 7:17pm

4 days ago, my right-side steering spindle failed when hitting a pothole at 40 mph. The spindle had roughly 60,000 miles on it.

My hypothesis regarding how it failed: while riding in a rural area last month near St. Charles, MO, I hit a racoon at 40 mph after it ran out in front of me with insufficient time to avoid it or brake, subsequently ramping more than a foot into the air and landing hard on the right side front wheel at speed, causing a crack to form. The pothole I hit 4 days ago at 40 mph, also on Kingshighway, caused the tab near the axle insert to shear apart and for the spindle to bend out of shape. Now the right-front wheel rubs against the body shell because the bent spindle has adjusted the camber to be more steep and the KMX is thus unrideable.

I've been trying to find a replacement spindle, without success. It appears KMX has stopped selling to the North American market and none of the former US distributors that I contacted have replacement parts.

I'm going to bring the spindle to a friend's shop and have it bent back into place and welded, but this is at best a temporary fix. I may have to fabricate my own, which at least has the advantage of allowing me to make a sturdier design.

Looks like I'll be using the Milan for all my transport needs until I get this sorted out. Which means I have to map out any routes I ride to avoid potholes, because shallow potholes the KMX could handle without issue would easily rip the bottom off the Milan.

I'm waiting to hear back from kmxkarts.co.uk about getting a replacement, and some spares. If that is not possible, I will have to fabricate my own, which will give me an excuse to make a sturdier design. The spindle appears to b the weakest link in the chosen platform, so addressing that would make the chassis rugged enough for the higher speeds I plan on riding.
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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Chalo   100 GW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by Chalo » Jan 04 2022 8:38pm

Now perhaps you better appreciate one of the drawbacks of small wheels, whether suspended or not.
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: My first ebike build: custom-built KMX-based electric velomobile

Post by Triketech » Jan 04 2022 10:12pm

Sorry to hear about the spindle failure. Heard that KMX was scarce but thats about all I know.

They sure aren't getting any cheaper, just saw new Ti-Fly 20, Rohloff, Shimano Mid Drive, decked out, MSRP $15K.
Zack Kaplan Cycles in case you just won the lottery. Too slow, but it's amazing folks will pay that much; and they do.

Anyway best of luck on getting back on the road. Maybe a little more frequent framework inspections too.

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by CTMonn » Jan 17 2022 12:17pm

I'm sure we have some members in the UK that would be willing to help. Try contacting them and asking them to buy the parts and mail them to you. It would be much quicker, cheaper, and easier than purchasing the CNC mill and making your own.
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I was warped and twisted. 8)

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by ZeroEm » Jan 18 2022 9:29pm

Don't think the KMX front spindle is like the rest of the trikes. Then again don't have one and only seen pictures.
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The Toecutter   100 kW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Jan 19 2022 4:35pm

CTMonn wrote:
Jan 17 2022 12:17pm
I'm sure we have some members in the UK that would be willing to help. Try contacting them and asking them to buy the parts and mail them to you. It would be much quicker, cheaper, and easier than purchasing the CNC mill and making your own.
One of them just contacted me. Hopefully I can still get the part. At the very least, I'm going to have to use it as a basis for a more sturdy design, especially if I'm going to put a roll cage on this thing, build some motorcycle wheels off of some spare hubs in my possession, install hydraulic disc brakes, and set it up to cruise at car-appropriate highway speeds.

The 3rd generation spindle design I was using is scarcely adequate for 35 mph. Hitting the raccoon at 40 mph is probably what caused it to crack. I need something about 5x as strong. The frame is still straight after all those miles, and a roll cage welded to it will stiffen it up nicely. The rear dropouts are another story!
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Jan 24 2022 10:20pm

While I'm trying to get a replacement part, a friend of mine was kind enough to bend the damaged spindle back into shape and weld through the cracks. I'll probably have time to re-install everything sometime this weekend.

I'm not sure how well it will hold up in the long term. I definitely need replacement parts.
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by uPET » Jan 25 2022 8:01am

Glad you've got it repaired for now. Hopefully we can track down some replacement parts :)

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by CONSIDERABLE SHOUTING » Jan 25 2022 7:34pm

Hey Toecutter, have you seen AirShaper? If you haven't built the body yet, it might be useful :https://airshaper.com/
The Toecutter wrote:
Dec 31 2021 11:31am
A lighter hub motor build with quality design and components, perhaps a high-efficiency non-PMDC design type with no cogging losses, to allow Leafbike levels of power, at half the weight or less, for me would be ideal. No one makes it for hobbyists at this time, even though many companies have demonstrated prototypes. AMZ made a geared hub motor of 7 lbs that could do 50 horsepower peak.
That sounds awesome. Do you have any links to it, or pictures?

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Feb 17 2022 9:55am

Thanks to the help of uPET, I was able to get in contact with KMX and a replacement part is on the way.
CONSIDERABLE SHOUTING wrote:
Jan 25 2022 7:34pm
Hey Toecutter, have you seen AirShaper? If you haven't built the body yet, it might be useful :https://airshaper.com/
I have not used this. I only have a Linux computer and an old Windows XP machine that can't run newer programs, so I need to get a newer Windows machine to use all of the easy-to-use applications to make my models and to make cool things like this work. I hate Windows, but getting some things to work with Linux can take more time than it would to build a body shell, and my time is quite limited right now.
That sounds awesome. Do you have any links to it, or pictures?
The source link is now defunct, but here's a quote from the article:

The four self-developed AMZ M7 wheelhub motors deliver 38.4 kW each at a weight of just under 3 kg. A staged planetary gearbox transmits the motor's torque, resulting in 375 Nm at the wheel. Thanks to an advanced vehicle dynamics control including torque vectoring and traction control, the ...

Here's the topic where the link was originally posted with a CAD image of the motor still present:

viewtopic.php?f=34&t=64509

Just ONE of these powering my rear wheel would be crazy. That would be sufficient for what is primarily still a pedal powered conveyance to out-perform most cars when the motor is used to its potential.

But imagine a car built on the concept of a velomobile, bicycle parts gutted, 4th wheel added, with all wheel drive with one motor powering each wheel, a 2 lb 130V/400A FOC controller running each, and a LoneStar pack of about 20 lbs to drive all of it! One could feasibly fit this package in a vehicle of under 150 lbs and keep weight that low while having the vehicle mechanically stout enough to handle it all. Hoonigans would shit a brick!
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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Chalo   100 GW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by Chalo » Feb 17 2022 12:20pm

The Toecutter wrote:
Feb 17 2022 9:55am
The source link is now defunct, but here's a quote from the article:

The four self-developed AMZ M7 wheelhub motors deliver 38.4 kW each at a weight of just under 3 kg. ...
Hmm, I wonder why the link is defunct? Those are definitely put-up-or-shut-up claims, so maybe they opted to shut up?

Anyone can claim whatever thing they imagine. The one who chooses to huff their hot gas might have a problem, though. It seems like you have a special affinity for fictionware.
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: My first ebike build: custom-built KMX-based electric velomobile

Post by CONSIDERABLE SHOUTING » Feb 17 2022 1:04pm

I just realized- no matter what, if you begin to use Waveshaper eventually you're velo will just look like a mini Aptera 8)
The Toecutter wrote:
Feb 17 2022 9:55am
I have not used this. I only have a Linux computer and an old Windows XP machine that can't run newer programs, so I need to get a newer Windows machine to use all of the easy-to-use applications to make my models and to make cool things like this work. I hate Windows, but getting some things to work with Linux can take more time than it would to build a body shell, and my time is quite limited right now.
I'd take a look into it, if only because it's very easy to keep Window's intrusiveness into your personal life very low if you know what they're looking for, and because Windows 11 can be had for free easily. Besides, a basic optiplex can be had for next to nothing and be built to preform well- my friends and I all have some that were literally being thrown into the trash working as home servers- and if all you're doing is waveshaper and 3D printing it's not like windows can get much out of you anyway.
Look into "Optiplex gaming builds". I've almost done one for kicks.
Here's the topic where the link was originally posted with a CAD image of the motor still present:

viewtopic.php?f=34&t=64509
That link going defunct sucks ass; like Chalo, a lot of things could have happened from the creators going bankrupt to even just simple site technical problems. If a motor like that is possible, you're in territory of your 0-60 MPH time depending on your tires. You're in Koenigsegg power:weight territory. I'd take on debt just to get in on that ground floor.

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Feb 17 2022 7:18pm

Chalo wrote:
Feb 17 2022 12:20pm
Hmm, I wonder why the link is defunct? Those are definitely put-up-or-shut-up claims, so maybe they opted to shut up?

Anyone can claim whatever thing they imagine. The one who chooses to huff their hot gas might have a problem, though. It seems like you have a special affinity for fictionware.
There was a video of a car using those motors accelerating from 0-60 mph in around 1.8 seconds. So some credibility was lent to their claims. Even if the motor was 1/2 as good as claimed, it would be very useful for my application were it made available. It certainly doesn't violate the laws of physics and is within the realm of plausibility/possibility.

All of the EV drivetrain parts needed to make the vehicle I want to build possible do exist today as off the shelf solutions, except for the motor. But the motor technology does exist in prototype form. Everything else, the batteries, controllers, computer, to make it possible, are all available to hobbyists. The motor is the only thing missing.

I have a notebook with a design for a monocoque chassis drawn up that may or may not get built. I have a long way to go before translating that into something usable, and will likely go through multiple iterations before I actually build something from it. But the idea is to use my purchased Milan SL as a starting point to guide a new vehicle design. Its aerodynamics are very good and the aerodynamicist who designed the Milan knew what he was doing. Without a motor, I can reach roughly 50 mph on flat ground, simply pedaling it. I want to make a vehicle similar to that, but more mechanically stout, more suited to crap pothole-laden roads, maybe not as aero but close enough, and shove car-like levels of power into it. I'm probably going to break stuff along the way. Maybe even die.

The vehicle I built off of the KMX was a good first build. It used to exist in my head as fictionware and some people on this forum told me it was impossible. But I built it, partially thanks to advice you gave me(and it is much appreciated). When it was running, I could top out at over 45 mph and get a 150-200 mile range @ 30-35 mph with light pedaling. 2500W in my custom build was more than enough to keep pace with automobile traffic including going up steep hills, and dudes on gasoline powered mopeds didn't have a prayer keeping up with it. And it weighed only 90 lbs, and was still pedalable with the motor shut off at a FASTER rolling average than the much lighter naked KMX trike was. My goals outlined 7 years ago were mostly met with my first build. So much more than that is possible. Compared to the Milan, its aerodynamics are utter crap, and improving that one aspect by itself will open up a lot of possible design outcomes, many of them which would seem outlandish.

If I were to move the EV parts to the Milan, I'd likely get more than double the range per charge, that is, 300+ miles range @35 mph, possibly as much as 200+ miles range @ 40 mph, on less than 20 lbs of batteries. I'd also probably break something, being that the Milan was not designed for hard accelerations or cruising 40+ mph on pothole-laden roads, especially with its 3" ground clearance. The irony is that regarding rolling average in a hilly area, I'm as fast in the unmotorized Milan as I am when using 350W of assist in my custom build for the same pedaling effort; even set at 2500W of assist, my custom build has a slightly lower top speed than the completely unmotorized Milan(albeit the custom build's top end is greatly limited by the 48V battery pack and the 4T motor wind, since I'm only drawing ~600-800W at top speed with very hard pedaling according to the CA3. 2500W is probably enough power to reach 70 mph in the custom build with its current crap aerodynamics, and that's theoretically possible with a 3T wind motor powered by a 72V pack, which would be quite an accomplishment if reached using the humble Phaserunner).

I'll get it going again soon. I have a 3T wind 1500W Leafbike motor and an ASI BAC4000 controller in my possession. I also have a truing stand to build up some light-duty motorcycle wheels, and have a hydraulic disc brake system waiting to be installed(I need to design a larger fluid reservoir so I can store more mineral oil). 72V is going to move quite nicely, albeit the spindles will still be the weak link. I need to design stronger spindles so that I can safely cruise faster than 35-40 mph.

The next iteration has me setting my sights on a 70+ mph top speed and acceleration comparable to a 4-cylinder new car. Like my first build conceptualized 7 years ago, it won't be fictionware forever. :twisted:
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by CONSIDERABLE SHOUTING » Feb 17 2022 9:03pm

I'd just message the manufacturer and ask why it was taken down. Hell, I'll do it too.

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by Chalo » Feb 17 2022 9:37pm

The Toecutter wrote:
Feb 17 2022 7:18pm
Chalo wrote:
Feb 17 2022 12:20pm
Hmm, I wonder why the link is defunct? Those are definitely put-up-or-shut-up claims, so maybe they opted to shut up?

Anyone can claim whatever thing they imagine. The one who chooses to huff their hot gas might have a problem, though. It seems like you have a special affinity for fictionware.
There was a video of a car using those motors accelerating from 0-60 mph in around 1.8 seconds. So some credibility was lent to their claims.
Yeah, because there's no such thing as movie magic.

https://www.dailymail.co.uk/video/news/ ... otion.html
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

calab   100 kW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by calab » Feb 17 2022 9:47pm

Sounds like a reputable company to me :lol:

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The Toecutter   100 kW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Feb 17 2022 9:59pm

Chalo wrote:
Feb 17 2022 9:37pm

Yeah, because there's no such thing as movie magic.

https://www.dailymail.co.uk/video/news/ ... otion.html
For this motor's specs to be false, the university that built the car that is claimed to have used the motor would have to be in on the scam. Possible, but Occam's Razor suggests against it.

https://newatlas.com/electric-car-world ... d-89811358

Although in a practical sense, even if it's real doesn't matter much if I can't buy it.

The peak power attainable for a given amount of copper/iron in a motor varies as an inverse of the function that describes the heat generated by the motor when running at peak power. This is why increasing efficiency matters so much.

The Leafbike variants are about the best I can get for now, which means 17 lbs of motor for about 13 horsepower peak and 4 horsepower continuous, best case scenario with lots of cooling mods. That's already been achieved by members of this forum. My limiting factor regarding acceleration will be the coefficient of friction of the drive wheel's tire. More power/torque won't be of any help beyond the maximum that can be used which is imposed by that limitation. In any event, neglecting wheelspin, that single motor makes enough power to make a vehicle with a laden weight of 300 lbs and 2x the drag of a Milan SL cruise at 90 mph until the battery runs dead without overheating the motor, and top out at over 110 mph for brief periods, and if enough traction can be had and if the rider has the strength of an athlete when adding thrust via pedaling, accelerate from 0-60 mph in under 8 seconds. A vehicle with this sort of mass and aerodynamic efficiency would get 100+ miles range @ 70 mph or 300+ miles range @ 35 mph to boot. And this vehicle would still be very pedalable as a velomobile with the motor shut off. I may very well pull this sort of performance off in a vehicle with a battery pack that weighs under 20 lbs and the vehicle itself weighing under 100 lbs. Math suggests it's possible. It's just a matter of building it.

Top speed and continuous speed:

https://ebikes.ca/tools/simulator.html? ... 0&mass=140

Range @ 70 mph:

https://ebikes.ca/tools/simulator.html? ... 0&mass=140

Range @ 35 mph:

https://ebikes.ca/tools/simulator.html? ... 3&mass=140

Further, an AWD 3-or-4 wheeled single-seater sports car with a dry weight of about 200 lbs using a Leafbike motor in each wheel could still perform quite ridiculously by car standards. Without a need to pedal it, a larger battery pack could also be justified.

The above two paragraphs are not a bad set of theoretical possibilities for a cheap Chinesey hub motor.

Things can only get better from here once better motor technology enters the market, and eventually, it will.
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

uPET   100 µW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by uPET » Feb 18 2022 2:29am

The motor in the link claims around 34 kW peak for just under 3kg motor mass. Not so different from off the shelf motors from China:

https://www.aliexpress.com/item/1005002 ... 4c4dNYusI7

Claims 30 kW peak, 15 kW continuous for 3.5 kg motor mass.

How these claims translate to the real world is anyone's guess - you'd have to buy one and bench test it, but they are being used in drones.

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The Toecutter   100 kW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Mar 18 2022 11:07pm

The part I need to fix the KMX is now in the U.S. There is no estimated date, but the tracking info notified me it will be late.

I'm looking forward to getting this going again.

The repaired spindle didn't fit correctly, and I will need to bend it back into shape, which I'll have the replacement spindle available as a reference.
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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The Toecutter   100 kW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Mar 23 2022 8:29pm

The spindle arrived today.

Thanks to uPET for getting me into contact with KMX so that I could get this part.

This weekend, I'm going to bend the repaired spindle back into shape and get my electric velo operational again. The replacement spindle will serve as a backup component, and as a template to engineer a custom spindle that is a lot stronger.

If I make it to the shop, maybe I'll have time to take the tail off and install the rear shock and new 20" Leafbike wheel-motor too. That would allow me to take the measurements needed to finalize the next body design.

In the mean time, I've put almost 5,000 miles on my Milan SL since purchasing it last year, completely unmotorized.
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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The Toecutter   100 kW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by The Toecutter » Apr 09 2022 8:26pm

I got the KMX back together. Tomorrow I'm going to my local bike shop to get new brake cables, brake cable housings, and cable lube. Sitting for so long has caused everything to seize up, and the parts were already old before the spindle broke.

She might be riding again tomorrow. That is the goal at least.
Custom electric velomobile, 2500W: viewtopic.php?f=6&t=110298

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ZeroEm   10 MW

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Re: My first ebike build: custom-built KMX-based electric velomobile

Post by ZeroEm » Apr 10 2022 8:07am

Bikes don't like sitting, like mine has this winter. I will need to re-lube the bike and wax the chain again. Happy that you are getting it back on the road.
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