Concept to reality - Build Thread

[SHiFT]

This is the build thread for my new project, as yet unnamed. I'll be moving slowly, but will post progress here as I make it - mostly for the record-keeping.

GOAL
A lightweight urban commute vehicle with the speed and handling of a motorcycle, but the ease of use of a scooter.

Construction:
Custom frame.
Off-the-shelf components where possible for easy maintenance and repair/replace.
Semi-modular build philosophy so components can be upgraded or exchanged without re-engineering the frame.

Speed:
50 mph

Weight:
<150 pounds

Features:
Onboard charging (if feasible)
NHTSA-approved lighting
NHTSA-approved safety equipment

Motor:
[strike]Agni 95R[/strike]
Hubmonster by John in CR

Drivetrain:
Zero DS Belt drive - 98/25
http://www.zeromotorcycles.com/shop...ducts_id=181&zenid=adr2sa2di0vdcfjcpclktl0ld2


Controller:
Alltrax AXE 7245

Battery:
[strike]Not sure yet[/strike]
Leaf Modules?
Telsa 18650


Specifications:
28 degree rake
56.5 - 57.0" wheelbase
4" trail
[strike]33" seat height[/strike]
29-30" Seat Height

I will be basing my design on the frame from the Husqvarna E-Go concept bike.
http://www.gizmag.com/husqvarna-80kg-all-electric-concept-e-go/19809/

Thanks for looking!

SHiFT

Edit: This is the continuation of this exploratory thread - http://endless-sphere.com/forums/viewtopic.php?f=10&t=62093

 

[CVillalobos]

Good times! I'll be watching.

 

[agniusm]

Why not get something like a 50cc enduro frame? Someone recently posted a new topic on derbi senda: http://endless-sphere.com/forums/viewtopic.php?f=12&t=68652
I love it, simple, saves tons of work. Have you thought about it, you still can heavily modify it but the biggest thing - geometry is there.
EDIT.
Also i dont understand why you want to go with such high voltage? Do it 48V so you will have to do lesser reduction. ~6000rpm is something.
At the moment i bought Navitas TMP-400 controllers and from the description i like it It has built in precharge, has also regenerative braking built in, couple other features. Its probably a bit under powered for Agni @200A continuous vs. 230A for Agni

 

[SHiFT]

Hm, all good information. Thank you.

Senda frame - I had seen that, and for a long time I was contemplating getting a frame from the UK shipped here and modifying that - Senda, Aprilia RS 50cc, KTM 125 Duke, etc.
It's a good idea, and less costly, but I have had a particular bike in mind since before I started my first bike in 2011. So, I am trying to build that bike. It's purely a vanity thing, as this is not the practical route.

Appreciate the thoughts on the motor and controller. I'm looking for speed and pickup for urban traffic, but doing the math, that 70V+ puts me at very high speed, and I don't know that I need that. Actually, I have been wrestling with that exact thought lately, which is "With that much power, how many seconds will I get to ride the bike before I kill myself?"

48V is more sensible. There should be no added stress on the Agni running it at rates lower than recommended, correct? Maybe loss of some efficiency, but there shouldn't be actual damage to the motor...

SHiFT

 

[Ohbse]

Very cool project and very similar target as something I've been working on in the background for a while now.

May I ask why you went with the Agni? I personally don't have much experience with the brushed stuff, but in general reading around here and around the issues experienced with the older Zero bikes that used the Agni's it seems like a power dense but finicky and maintenance prone option.

I don't have any desire to deal with replacing brushes, 'tuning' or any of the other downsides so I was set on brushless. A couple of people in your initial discussion thread mentioned John in CR's hubmonster as a good option. It's a little heavier, but comparable in physical size. Configured in a mid-mount arrangement there's probably a good few kg that could be trimmed as it's an overbuilt hub motor designed for wheel loads at motorcycle weight. Power handling is excellent and capable of 30kw peaks. One of its more unique features is it is wound as two distinct 3 phase motors, this requires the use of dual controllers which in this case is actually an advantage - you can use a pair of 10-15kw capable controllers which are compact, affordable and reliable to deliver power that would ordinarily take some much more expensive and difficult to configure controller like sevcon etc. Added bonus is the motor is very affordable.

Have you got any plans for a fork? I've been struggling with options in this area.

 

[agniusm]

Read about those Agni motors. At 72V its almost at max voltage (84V) and redline rpm. Doing it at max is no good for anything. I think 60V is good, 16S lipo or 18S lifepo is a sweet spot for 3000rpm.

i suggested that controller from Navitas, cause you can get it of eBay for 130USD. Thats cheap. Plus it has futures, alltrax does not. I have 4845 alltrax and its good, solid, but i have ordered Navitas tmp-400 to play with. The only down side is 250USD programming cable, but i bought 30USD CAN and will try to figure out programming.

Ohbse, i have 2004 blade with even older Etek motor with solid brushes. The whole thing is to use motor as recommended by the manufacturer. If you overdrive a motor - prepare to replace brushes more often. Drive a motor within spec. and you will forget about them.

 

[SHiFT]

Actually, a Hubmonster does sound like a good option given all the comments. Sorry to Arod for missing that in his suggestion. I misread it as being a hub mount-only option, didn't process the recommendation to use it in mid-mount.

It would be air cooled, but being fixed in the frame (rather than spinning in the open) should reduce the air flow drastically. Do I need to worry about overheating it?

Fork:
I am actually thinking of using a Cannondale Lefty fork
(but not the 29 inch size).
http://www.artscyclery.com/Cannondale_Lefty_Supermax_Carbon_PBR_130_29_Fork/descpage-CDLFK1329.html

The choice to go with that is weight, as standard Motorcycle forks are very heavy. I am worried the Lefty is weak for a high speed vehicle like this, so I'm checking with Cannondale on the strength. My current backup plan if the fork is too weak, is to get an fork from a smaller bike, something like this one (this is inverted, which is also nice):
http://www.yamaha-motor.eu/uk/products/motorcycles/mt/mt-125.aspx

 

[Ohbse]

I would say single sided fork is pretty much only for looks at this point and given what the rest if the bike is going to weigh the fork is one area I wouldn't be hunting for grams.. If you want strong and lightweight then dual crown downhill bicycle parts are very hard to beat.

Something like a fox 40, Marzocchi 888 would be best performance/safety per kilo. The one area that you may struggle with is getting enough brake to bolt on easily. High end bicycle brakes are good but borderline for this much weight and speed. The service parts are also expensive and pads comparatively tiny.

I have been looking at some of the higher end pitbike forks as these are along similar lines to DH components just beefier all round. Heavier but much less so than most motorcycle forks intended for much heavier bikes. Various easy bolt on and affordable brakes intended for use at these speeds/weight.

 

[agniusm]

I agree with above. Single sided for is for looks and casual city driving. It is complete nonsense to use it on such bike unless you want it in a show room
Would be interesting to see that 6kw hub motor as mid drive. Note that it needs two controllers thou. The wight could be reduced by milling out vents and trimming whats unnecessary.

 

[sk8norcal]

subscribed

 

[SHiFT]

Frame is coming along.

I will further refine this as I get closer to finalizing the components and the battery size/layout - To that point, I think I'll use Tesla cells, but not sure what config to go with.

I think I will go with a hubmonster too, instead of the Agni. The motor is more robust and almost as light.

Stay tuned,

SHiFT

 

[agniusm]

You see your rear swing arm pivot, i would design it around the hub motor so it would fit there and the swing arm pivot would be clamped motor axle.
I don't know about Tesla cells. modules are too large and taking apart cells will require serious commitment. I see leaf modules being good option, only thing i would do on my build is loose the cans and make aluminium box so it fits tight.
I have done Leaf module for my brothers bike but he didn't waned to cut out the cans:
The bike:

Battery:

 

[SHiFT]

Very nice bike.

I am thinking the swingarm pivot will also be the front sprocket to eliminate driveline length changes over bumps and uneven terrain. But I was thinking of doing a reduction from the motor to the swingarm pivot, like a DaVinci Drive, then over to the front cog and back to the rear cog.

Leaf modules - I hadn't considered the need to repair only a cell or two in the battery (you helped me avert a noob mistake). That would indeed create quite a lot of difficulty for me. The Leaf modules are pretty easy to use it seems, great idea thanks.
I am planning to vent the front of the battery housing well too, so I could easily stack these in a way that they can be swapped in and out, and still have room for airflow.

SHiFT

 

[agniusm]

Dual reduction = more looses. With hub motor you only need single reduction because of low rpm.
I dont know about venting the battery on a dirt bike.

 

[agniusm]

This is off topic but axe is reliable for me and it is sealed. I have same usb programming with rs232 to usb cable. No issues there.

 

[SHiFT]

Getting there.

The final bike will probably have some details changed, but it's largely complete.

 

[Ohbse]

Looks very cool. Using solidworks?

Do you have a source of the swing arm lined up? Single sided is very cool, but it makes life a lot more difficult when it comes to sourcing properly lightweight and affordable components like wheels, hubs, brakes etc... unless you have a complete donor in mind.

I see you went with a double stage reduction on the pivot mounted jack shaft - this really isn't required if you're planning on utilising a Hub Monster (which you should, they're awesome).

I can run some numbers for you once I get home if you've got a specific size of rolling stock in mind, but with what I've got so far with a 17x3.0 moped tire and a 110 km/h top speed only requires a ratio of 1.2, or put another way something like a 19 tooth with a 23 tooth on the rear from memory. Reduction is really not a problem, unlike if you're using a smaller RC type motor.

In an ideal world you would utilise the motor axle AS the swing arm pivot. Obviously the axle is more than strong enough for this. You then have a choice whether you lock the reaction torque of the motor to the swing arm or to the frame. Opinions vary as to which is most beneficial, but everyone agrees a mild single stage reduction with no tensioner is the best possible option.

 

[SHiFT]

Yes, I may have to go with a standard rear swingarm. That's fine. If I can find a donor, I'll go with that, but you are right - weight will likely be the limiting factor, even if I find a donor.

If I make the motor output shaft the rear swingarm pivot I couldn't use a single-sided swingarm in this configuration anyway. So I've designed it with the "ideal" from a cosmetic standpoint, but may revert to the tried and true when it comes down to building it.

Thank you,

SHiFT

 

[Willow]

subsribed

 

[SHiFT]

OK, frame done.

I will likely not use the swingarm as modeled, though, given all the feedback I've received, thank you.

The seat support will also likely change, as I will move the seat down some from the concept for a lower seat height.

 

[RobertC]

Subscribed. I have similar thoughts to you.. I am also in planning on building a mid-mount drive ebike.

What material would you be building the frame with? Standard chromoly steel? The design shown above has some bends near the front. Does that complicate things?

I am in Vietnam, and there are more motos than people. Something like 100 million scooters. I am looking to use stock, common parts whenever possible as labor is cheap and parts are super easy to find. Tires, Rims, disc brakes, gears, chains, I will probably use 150 cc motorcycle parts to start with. Anything that starts to wear or looks ready to break will get replaced.

But I had some different ideas for the motor. Have you read this thread ( http://endless-sphere.com/forums/viewtopic.php?f=31&t=65972 ) about the QS motors? Good efficiency and under 300 USD for 2-3 k-watts continuous power.

For batteries I am thinking the large Headways simply for ease of assembling the packs: http://www.evassemble.com/index.php?main_page=product_info&products_id=175

A123 prismatic looks like it would work as well, but I am concerned about fakes..

 

[SHiFT]

Robert I'll respond to you, but I also have a question to ES members at large at the end.



Why custom:
Vanity for the most part. Secondly, light bikes like the 150cc bikes you have in abundance there are not available here. It would be almost as costly for me to custom build something, as it would be to buy a bike unseen/unridden from overseas (UK, Asia, etc), ship it here, then customize it once it has arrived. And if I made a mistake with my first frame, and it won't work, I have to start over.
I have specific needs that I want to address which would almost certainly require modifying any frame at least some, so researching online and buying without ever seeing the bike, feeling the dimensions, or the weight would not be wise.

I would agree though, in your situation, I'd also use an existing bike and modify as few parts as possible. I'd pick an actual motorcycle not a scooter. And because I know terminology may be different, I would say I consider the Honda Wave, PCX, and Blade to be scooters. The Honda Win is more of a motorcycle. I only say that, because you are going to have a lot of engineering and fabrication to do if you get a motor and transmission combination like many scooters. Often the transmission is a CVT that is attached to the motor and also performs the function of the swingarm. That's a big pain I'd avoid. Many of the concerns you have are factors in my design as well. What I want to build is basically an electric version of Honda Win which you find everywhere in Asia and even some places in Europe. Basically, a bike with the weight of a scooter, but the looks and speed of a motorcycle.



ES:
I'm working now on a design around the frame I have had made. I could use some input on how you think I should execute making the motor and swingarm pivot one unit. I'm not envisioning how the swingarm will pivot and the front cog would all work integrated together. I don't see a way I can have the output shaft go through to the frame without an additional bearing on the frame to spin with the output shaft. But is that the best way?

Thanks,

SHiFT

 

[RobertC]

Great reply! I thought supply of donor bikes would be a problem for you. How long is your riding season without needing arctic gear?

Some other random points:
1) Your previous post was flawless English.. I read it twice, the second time looking closely, and spotted zero errors. Perfect.. I teach English and notice these things.
2) I am guessing you are an engineer, due to the CAD work etc.
3) Will you be fabricating the frame, or contracting with a machine shop?
4) Do the curves at the front of the frame add much difficulty to the build? Is it easier to go with straight stock?
5) What material for the frame?
6) I am not sure that Scooter and Motorcycle are rigorously defined terms. I personally would say a scooter is something with a flat deck for your feet. A 90-150 cc motorcycle is straddled by the rider. Differences between the Win and the Wave is maybe a slight difference in size, and placement of the fuel tank, waves have it under the seat, the win has it on top in front of the rider. The rest of the parts should be easy to swap. The scooters and Waves also have some plastic fairings, where the Win is bare of any body panels.

For a donor bike I want something with disc brakes front and back, with chain drive. Also, I want the engine to be "Bolt On" not an integral part of the frame! ie. unbolt the engine/transmission, disconnect all wires and fuel lines and it should simply fall on the floor leaving the bike ride-able downhill.. There are many of these 4-5 years old available. Newer bikes are mostly CVT as you mention. More expensive to buy used, and more parts for the bin after conversion, so not as interesting.

As for the swing-arm mount, I think go simple and brute force. 1 inch OD sealed bearings for 1-2 USD each, and some 1/4 inch steel plate sized and drilled to attach the mid-mount motor. This should be plenty strong.. Or maybe put the bearings in the ends of the swing arm? It might be easier to specify a motor with a straight-through drive shaft which would avoid any alignment issues with the swing-arm. Stick with standard industrial style motor mounts and trim to fit the space allowed. This part should be easy. Something like the pictures here: http://www.instructables.com/id/Engineer-Your-Own-Electric-Motorcycle/step4/MOUNT-MOTOR-BATTERIES-CONTROLLER-CHARGER/ but with the motor mounted 6-7 inches further back towards the rear wheel, eliminating the "L" shaped vertical swing-arm mount. Perhaps cut the frame along the weld where the new motor mount is attached then mount a U shaped engine mount in its place. Instead of a rain-drop outline go with something more rectangular and less pointed at the top of the engine mount.

Same idea for mounting the front end, cheap large industrial bearings.

I am most worried about the balance of the bike. Frame geometry, drive-ability, comfort, etc. Starting with a standard motorcycle most of these are close to "correct" and have been tested and refined for decades. But I do find most of the standard scooters you mentioned to be a bit cramped. An extra inch here or there in the build process should hopefully not change the engineering too much.

You mentioned moving the seat further up the thread. This scares me a bit as it would drastically change the Center of Gravity of the bike, and the position of the handle-bars relative to the rider. FYI, I am 5 feet 10 inches tall (saw you used inches in your posts above) with about 30 inch inseam for trousers. This is "Medium" sized for a man in the USA, but in Asia, I buy XL or XXL clothing. Small motos and scooters are sized a bit smaller than me usually. I might stretch a stock donor bike 2 inches longer, and an inch or two more height between the foot pegs and the top of the seat..

 

[SHiFT]

1) Your previous post was flawless English.. I read it twice, the second time looking closely, and spotted zero errors. Perfect.. I teach English and notice these things.
2) I am guessing you are an engineer, due to the CAD work etc.
3) Will you be fabricating the frame, or contracting with a machine shop?
4) Do the curves at the front of the frame add much difficulty to the build? Is it easier to go with straight stock?
5) What material for the frame?
6) I am not sure that Scooter and Motorcycle are rigorously defined terms. I personally would say a scooter is something with a flat deck for your feet. A 90-150 cc motorcycle is straddled by the rider. Differences between the Win and the Wave is maybe a slight difference in size, and placement of the fuel tank, waves have it under the seat, the win has it on top in front of the rider. The rest of the parts should be easy to swap. The scooters and Waves also have some plastic fairings, where the Win is bare of any body panels.

1. Thanks. I majored in English in college, so I should have decent grammar. Although, I do have a habit of using erroneous commas where I would pause in natural speech. Surely, I've done that above.
2. I'm not, but I hired a designer to build the frame in CAD so...
3. A shop can build the frame for me. I live in a high-rise with no tools or workshop. I'll focus on putting the bike together and leave the heavy-lifting for a shop with the right resources.
4. Yes, normally it does, but by how much depends on the complexity of the curves. I am hoping these are not too complex to make the cost/effort prohibitive.
5. I'd like to use aluminum. I know aluminum is not as strong as steel, hence the elaborate machined frames of most aluminum bikes. However, I spoke to a local builder who said in a lightweight bike with enough trellis in the frame, aluminum should be strong enough. I may consider titanium if it is not outrageously priced.
6. Yes. I think you are right. I lumped them together not because that is US terminology, but because that is how I characterize them being in a country without any of these style bikes for retail sale, of which I am aware. Though I acknowledge that I am probably wrong - Your dividing line makes much more sense and is more unilateral than my subjective definition. I would call the Wave a step-through frame, which gives it a scooter look in my opinion.

For a donor bike I want something with disc brakes front and back, with chain drive. Also, I want the engine to be "Bolt On" not an integral part of the frame! ie. unbolt the engine/transmission, disconnect all wires and fuel lines and it should simply fall on the floor leaving the bike ride-able downhill.. There are many of these 4-5 years old available. Newer bikes are mostly CVT as you mention. More expensive to buy used, and more parts for the bin after conversion, so not as interesting.

Entirely agree.

Geometry:
I agree about the concerns for balance and feel. This is something I'm going to have to take a chance on. I have in mind many variables such as steering angle, seat height, distance from foot peg to ground, trail, etc, based on popular bikes like the Triumph Bonneville, Honda Rebel, and Ducati Monster. I'm hoping that if I follow standards and geometries of other popular bike frames, I'll end up with something which has generally agreeable ride comfort and feel for basic commuting, even if it is slightly awkward in some conditions. Still, I can adjust the geometry once the bike is built, to a degree, so I plan to tune it quite a bit.

Size:
You are tall for Vietnam, heh. My mother is from Hong Kong, but I am 183cm tall, which is not at all unusual here. I don't know if you've ever sat on a Harley, or even Yamaha/Star Bolt. These are very large bikes, even for me. When I sat on the Bolt the first time, I felt like I was a kid grappling with a machine that was way too big for me. It was a strange experience, I can only imagine if you got one out there, and went storming through Hanoi or some place with a monster 1300cc Harley pushing hordes of 150cc bikes out of the way like a shark through a school of fish. Hah.

Thanks for the help on the pivot. I'm thinking I'll need to go that route with the bearing.

Ride weather:
In California, you basically never need cold weather gear, and only seldom need rain gear. You can ride year-round. I moved from California to Virginia 3 years ago, and here you can pretty much only ride in the summer, May to September or so. Of course, the weather changes, but generally, people do not ride during Fall and Winter. Even if you could protect against frigid/uncomfortable temperatures, generally, you don't want to get stranded if snow or rain falls after you are already on the road or at work.

 

[SHiFT]

Removed duplicate post