GoldenMotor.com Forum
General Category => General Discussions => Topic started by: Garm@n on January 18, 2013, 07:14:30 PM
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Hello, I'm new to this forum and I have been lurking the site for information. It seemed to make things worse. Anyway I would like to build a 12" folding ebike for transport to work. 32km-40km would be my target and have the ability to climb hills at a reasonable speed (20K).
I have looked through this site I spoke with Gary. He mentioned that he will be getting some 12" kits soon. (link)
http://www.goldenmotor.ca/products/12-Inch-Front-Smart-Pie-Conversion-Kit.html
My question is... is this just a hub and would I need to re-spoke my present rim.
- Will this fit my criteria I mentioned earlier.
Now if I need to add the rim to this hub. I was curious if it would fit. Looking at the measurements provided, the hub has a diameter of 188mm, roughly 7.4 inches. So I measured the inside of my rim on my bike and got 7.5 inches, this leaves me to believe it is either a hub/wheel kit or hub that will not fit my 12" rim. So in further searching I found another kit, looks the same, but with a wheel in the diagram and same make and model (link, scroll near bottom)
http://www.goldenmotor.com/
If this is the same unit, how do I get the hub to fit, maybe the diagram provided incorrect?
Or can anyone suggest a better solution for my 12" folding bike.
Also If I do buy this, will my current tire fit into this kit. The size of my tire is 12x2.25"
Thanks
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I guess no way to edit?
Anyway wanted to add 2 things. How would I add air to these wheels. I can see how the valve would be accessible. The other would anyone know how many rpm's this wheel/hub can provide.
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The item you are looking at is a complete kit. All you need is a tire, tube and a battery. The tire you have should be fine.
The description lists everything it the kit in the section Kit Includes:
Gary
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Thanks Gary
So I found the chart you mentioned, I'm not sure how to properly read the chart provided.
V A w PF Hz mN n rpm W %
01- 47.94 1.085 52.00 1.000 0.00 403.3 374 15.80 30.4
09- 47.94 5.680 272.32 1.000 0.00 6563.3 335 230.23 84.5
12- 47.94 9.780 468.87 1.000 0.00 11813.3 307 379.76 81.0
23- 47.88 14.989 717.69 1.000 0.00 38373.3 31 124.56 17.4
I came up with this figure that I gleaned from result 01-
The top RPM (374)produces a result of 13.3mph. Is that correct, or am I reading this wrong? Anyway this seems very slow at full throttle. Is there anyway I can tweak the controller to get me 20-25mph.
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Is this a motor for 12" wheel or a motor of 12" in diameter?
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well I measured my tire and it is a 12 inch diameter. now I am not sure what GM is selling me 12" diameter tire or rim size. let me know this is important, but again speed is a issue. the way it stands
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so, what's diameter of the motor itself? What's top speed? torque?
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frankly I don't know. I was hoping people with the 16" version would step up. or others with good exp provide suggestions, solutions.
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Is this a motor for 12" wheel or a motor of 12" in diameter?
The 12 inch wheel fits a tire that is 12 inches in diameter on the outside of the tire. The rim is much smaller. Just like on a 26 inch wheel the outside diamter of the tire is 26 inches and the 26 inch rim is much smaller. To order a wheel that fits your 12 inch outside diameter tire you order a 12 inch rim. Even though realistically its much smaller.
Over seas a lot of the world uses ETRT standards where a 12 inch tire would be 12 inches in diameter on the inside of the tire. The 12 inch rim would actually be 12 inches in diameter. And the tire much bigger on the outside dimention.
Gary
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What's a top speed of such 12" motor wheel with 24V battery? 48V battery? What's torque?
What's current consumption (continuous and peaks)?
Thank you!
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could you publish a link to the motor?
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i guess my last few post were deleted. I'm not sure how this helps my cause looking for solutions. So I will describe in words rather then posting links from other websites. so it doesnt get flagged as spam.
Since the 12" motor here has 2 problems 1. under powered 2 wheel size is not compliant to ontario ebike laws. I found a possible solution. another site carries a 14" wheel/hub kit but carries a external controller BUT pushes a 1000w. Some issues I do see is whether the wheel fits my bike and rpms is a about 150 more than the Smart Pie. The cost for the leaf motor kit is steep about 500$ including shipping, but I did not factor in duty, probably making this kit un-affordable. The question I was waiting for was....
are they under-rating motor or over stating the wattage, it seems to me a 1000w should exceed the Smart Pie specs in this case?
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Not sure why any posts may have been deleted. I know I didn't do it and Alan is against censorship. So I Imagine "Big brother" GM China is watching and maybe they didn't like them. The motor you had shown before it was deleted looked like a 901 in a 14 inch rim. That would be 50o watts at 36 volts and 1000 watts at 48 volts.
I think you need to decide about street legal issues. In one sentence a 12 inch wheel is to small for street legal and in the next you are looking for 1000 watts. I know you are trying to figure out how fast the 12 inch wheel will go. In one post you state you found the chart I was referring to. I have no idea about any chart. You must be confusing me with another person.
I can present some logic about speed. I have a fair amount of experience with 26 inch 901 and 26 inch MP3. Flat out with 48 volts the 901 would do 48 kph in a 26 inch rim (50 in a 700c rim). Flat out with 48 volts an MP3 does 46kph. Both of them at 48 volts are considered 1000 watt motors. Of course these are not speeds you would do to be street legal this is just for comparison. The speeds are pretty close. At 36 volts they do 33kph and 32 kph respectively. Still very close. But now they would be considered 500 watt motors.
I have no experience with Smart Pies other then spinning them up for a test but people are saying the top speed of the Smart Pie is similar to the MP3. So at 48 volts a Smart Pie would be considered 400watts and will do 46kph and at 36 volts it would be 250 watts and do 32 kph in a 26 inch rim.
If anything I am saying so far makes sense the 48 volt 400 watt Smart Pie would be faster than the 901 at 36 volts 500 watts no matter what the wheel size. So if you are trying to stay street legal wattage wise the Smart Pie would be faster and in a smaller rim more suitable for your needs.
Also people are finding more torque then they expected on a 26 inch rim so in a smaller rim it would have even more torque.
That leads us of course to the wheel size issue again. If you are wanting street legal all the way then I think you need a different bike. I doubt a 14 inch rim will fit on your bike but of course I have never seen it or any pictures of it.
But one more thought is I have two folding Ebikes with 8 inch wheels. No one has ever taken a look at them other then to state how cool they look. I doubt they would ever present an issue, but with current laws I guess they are not street legal. That was my biggest complaint when I sent my submission in to the provincial study. What difference should wheel size make? Talk about a stupid rule just for the sake of making a rule.
Gary
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thanks for response and for the explanation about my posts. So you are right about 14" hubs, I'll put that idea to rest. So once again compromising is rearing its ugly head and will probably move to 16" wheel. Though14" is away to go. It would easier to fold smaller take the bus if failure or down pour occurs. Anyway I will head to a shop that sells folding bikes and take measurements.
Now this opens up a new avenue for me with the MP3. I'm curious if most just buy the kit or do others buy the monitor system attached to the bike. I also would like to know if rear hub better choice over the front hub.
BTW I'm guessing the rear hub is only free wheel. So no coaster brakes available?
I'm not sure why 350mm was the magic number by the government, I'm only speculating the government is trying to weed out the pocket bike riders. My fear if I am not fully compliant and since Toronto is one of the top 3 cities in traffic enforcement in Canada. I'd rather not receive moving violation or driving without insurance and license once the police notice the non compliant tires.
As for speed, I get them by reading charts provided from the manufacturer. Just take the rpm's convert the diameter of the tire to it's circumference multiply by the time and convert the total inches to miles and voila! mph... I think thats correct.
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I don't carry ready built Ebikes. The main reason is the cost of shipping from china to Canada makes it unrealistic and overpriced. Another is of the 4 I did import I kept them all for myself. There was never any interest for a pre-built bike. There are so many inexpensive bikes already here and kits like he MP3 are extremely easy to install. If you know anything about the battle for Ebikes going on in Toronto right now buying anything that resembles a scooter coud end up getting you off the road altogether. I recently converted my regular ride to having a pedelec. That way when I am in Toronto I can ride the bike lanes without issue. In Mississauga Ebikes can ride in the bike lanes and if they are under 88 pounds they can ride n the bike paths as well. So keeping it light would most likely be in your best interest, at least until the battle is over and the dust settles. Who knows where the lines will be drawn. The bicycle union is trying to eliminate the scooter style Ebikes all together from the definition of Bicycle.
A rear hub is always the best choice. Its best to have the power where the traction is. But some bikes have coaster brakes and no way to convert to regular brakes. Some people try to do the front to a balance the weight but end up just spinning out the front wheel on take off. Other people think messing with the gears is difficult or they want to keep there 8 or 9 speed freewheel. The reality is ones you have a motor the numbers of gears means very little.
Gary
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Gary do these kits come with a kill switch. Personal safety if throttle sticks. I know the battery casing has a key lock, I am presuming it's off/on, but impractical if it's behind me and low to the back wheel. Would be difficult to turn key if something goes wrong. Also once I choose the 48volt kit, would it still be possible to use 36v SLA battery as back up or during building phase to test motor and controller or is it just best to buy the battery with the kit. Thanks
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The brake levers have a wire to the controller that cuts the power and enables regenerative braking. Any 24, 36 or 48 volt battery will run the kit. The higher the voltage the more power and speed. If you are thinking of using cheaper batteries until you can afford something better you are not the first person to do this. Many people have started out that way. I have even seen some people using two or three old car batteries in a trailer to get started. That maybe a bit much for you and your folding bike though :)
Gary
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You mentioned something interesting. Once the hand brake is engaged the motor stops rotating, regardless of the throttle position. Right now the setup for my folding bike will be...
1 front wheel mp3 hub (16")
2 rear coaster brakes
3 front v brakes
4 eventually 48v LifePo4 battery
My questions are...
-the kit I buy will have 2 hand brakes I will only need one due to the rear coaster brakes. Problem?
-the front v brakes. Will the motor cut-off still engage or do I need disk brakes? regen braking also work with V brakes?
-will I be able to connect the new brake handles to my current braking system? (ie front v brakes)
BTW how water tight are these systems
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Hi. And Hello Gary.
I believe those charts include newton torque test readings with RPM and efficiency load voltage, for a 26" wheel.
I guess it was a tread mill setup. So the 12" should experience less torque at high RPM and wind up faster on load.
I think speed drops off with the 12" diameters a tad, more voltage 48v or higher can satisfy that and program your bike to go what ever speed you need.
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You mentioned something interesting. Once the hand brake is engaged the motor stops rotating, regardless of the throttle position. Right now the setup for my folding bike will be...
1 front wheel MP III hub (16")
2 rear coaster brakes
3 front v brakes
4 eventually 48v LifePo4 battery
My questions are...
-the kit I buy will have 2 hand brakes I will only need one due to the rear coaster brakes. Problem?
-the front v brakes. Will the motor cut-off still engage or do I need disk brakes? regen braking also work with V brakes?
-will I be able to connect the new brake handles to my current braking system? (ie front v brakes)
BTW how water tight are these systems
One hand brake is fine as long as you use it when you brake so it cuts the motor.
Regen braking works with v-brakes, disk Brakes, etc
To use the brakes. you just unclip your brake cable from you exiting brake lever. Replace the brake lever with the gm one and join the brake cable to it.
The internal controllers are fairly water proof as long as the motor is mounted correctly with the cable running water away from the motor instead of into it.
With the external controller wheels there are less water issues as the controller can be protected from water quite easily.
The main water issue seems to be when people seal the motor air tight casing condensation to be trapped inside.
Are you sure a 16 inch will fit on your bike? If so I have a front MP2 16 inch with external controller I'm selling used. Contact me by email if you are interested.
Gary
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Be careful with the axle width, I've just gone through making custom forks because I couldn't get 20" forks that were wide enough to take the Smart Pie, if you're just looking for a folding electric bike, I'd skip all hassle and buy one complete.
As far as speed goes if people are getting 40kph out of 26" wheels, then being a smaller wheel you're going to be maybe half that, because every rpm covers less distance, on the plus side if you halve your speed, you should have double the torque. I just took my 20" Smart Pie Trike out on the road for it's first run, and with only 1 20AH 24V LIPO4 Battery I estimate I'm getting around 20kph, not bad with a 130kg rider, it won't go up my 15 degree driveway, but I just have to use the pedals :) And I'm still waiting on the second battery to give it a go at 48v. I haven't hooked up the laptop and fiddled with anything yet, got to try the Pedal assist yet.
Hopefully get some pics tommorrow, maybe some video.
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Hey thanks for the advice. Since you are doubling the voltage would it not be correct that the rpm will double as well giving you 40km/h base on a 20' wheel. Also I'm speculating the 48v is really 58V giving you another 5-6km/h. So possibly your 20" bike can go about 45km/h and based on that figure and applying to a 16" wheel I would do about 35km/h or am I wishing these figures. Plus I weight 170lbs or 77Kg.
The odd thing I remember is reading the specs and when calculating the speed via rpm I was unimpressed with the speed achieved. 20Km/h is too slow for my liking. 32 is my limit for speed. I'm getting mixed messages, But I am curious as to how the Emmo urban is able to achieve speeds up to 40Km/h on 16" wheels and no mods. I think that is the size I read previously.
-Gary, about the 16" MP2 or MP3 I sourced out a 16" bike do you know how wide the axle width for mp2 or 3. Also can you tell me the difference between2 and 3.
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Well I don't think double voltage means double speed, more like some speed & extra torque & range, I'm only expecting an extra 50% at best. It's also possible I'm badly estimating my speed and only doing 15kph too.
Here's some rough calcs on the circumference of the rims using pi*diameter
16" = 127cm per revolution = 67% of 40kph = 27kph
20" = 159cm per revolution = 84% of 40kph = 33kph
26" = 188cm per revolution = 100% 0f 40kph
So my guess at half the speed is incorrect, more like I've lost only 15%, this is off the rim size so there's probably a bit more speed with another 4 inches of tyre added. So if I'm right the best speed you can get is 67% of what the guys with 26" wheels are getting, but you may have 33% more torque for climbing hills :)
I'm not sure my trike is stable enough to want much more speed anyway, I need to lower it's centre of gravity a lot, not being able to change the lean of the bike for corners and road camber feels weird :)
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Thanks again. I'm looking forward to see your trike build. I'm actually considering buying the bike whole as I will be in Florida in March. Do you know of any good stores that sell folding e-bikes in Tampa Florida or north of that location.
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Be careful with the axle width, I've just gone through making custom forks because I couldn't get 20" forks that were wide enough to take the Smart Pie
The Smart Pie axle width is 100mm front and 135mm rear. That is the same as all other kits I sell and is pretty much standard on 99 percent of all bikes made worldwide. I find it puzzling that you could not find 20 inch forks with the 100mm width. Or Is it because you have a folding bike and could not find standard 20 inch forks that would fit your bike?
Gary
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My original Trike forks were only around 90mm wide like a dragster bike with a 1" neck tube, my old mountain bike has the same width and 1" neck too. I looked and to find a 1" necktube 20" or even 26" forks 100mm wide with Disc brake mounting just weren't around at the local bike shops or the internet, I had also already brought a set of 26" forks with the wrong necktube so all I could do was cut n shut the 1" neck onto the 100mm wide forks. I wanted a chopper look hence the longer forks :)
It was just something I had never considered when starting the project that there was more than one size neck tube or front axle width. Now it's operational, hopefully I'll take it for it's first shopping run and get some picks of it on Monday if the sun comes out :)
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Both of those bikes must be old standards or unusual bikes. Here is a few modern day references.
Wikipedia states standard front forks 100 mm and 110mm on downhill bikes. My downhill bike was 100 mm front forks.
http://en.wikipedia.org/wiki/Bicycle_fork
Sheldon Brown states 100 mm front for modern bikes and a whole variety of sizes for rear wheels. But do you believe a guy with a gold bird on his helmet?
http://sheldonbrown.com/gloss_sp-ss.html
Gary