GoldenMotor.com Forum
General Category => Magic Pie & Smart Pie Discussions => Topic started by: Bikemad on October 27, 2009, 12:03:19 AM
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The Magic Pie is currently available with the following size rims: 26", 28" and 700c.
Smaller sizes, such as those commonly used on BMX, folding bikes and recumbents etc. could be produced if there was enough demand for them.
If you would like GM to consider producing the Magic Pie in a smaller size, please select the size wheel you would like to see made available.
(Please answer the above Poll)
16" rims (and possibly 18" rims as well) would need to be fitted with a solid, non-pneumatic tyre (http://www.amazon.com/dp/B000AO5MVS/ref=asc_df_B000AO5MVS946590?smid=A2TE9IQP68MWQU&tag=shopzilla_mp_1221-20&linkCode=asn&creative=380341&creativeASIN=B000AO5MVS) or solid inner tube (http://www.noflattires.net/cart.php?target=product&product_id=479&category_id=117) as there would be no way of fitting a valve.
An 18" rim for conventional tubed tyres might just be possible, but you would probably need to use one of these adapters for inflating the tyre:
(http://www.arhservices.co.uk/GoldenMotor/Valveadapter.GIF?)
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Some feedback. :D
I would vote 24" and 20 " so I just made the voting even with my vote.
A Pie on a 700c is nice. All that torque translated to speed. Yummy.
Really for a little dirt BMX e-bike gearless isnt all that practicle, however the Pie just looks to be good enough on a 20".
Recumbent, tandem or load carrier, shopping bike, for practical road and heavy loads use the a 24" heavy duty rim Pie would be fantastic.
There are uses for these dimentions, but how they apply to ones needs is important. I would love a 24" Pie.
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I too think they should make 20" and 24"
The 24" would offer that little extra torque with the smaller rolling diametre that would be beneficial to those with hills to climb.
I think there'd also be a market for the 20" for folding and BMX type bikes but the spokes would need to be replaced by cast alloy blades like these ones.
(http://www.goldenmotor.com/hubmotors/hubmotor-imgs/48v1000w.jpg)
I'd also like to see an option of different rims. My Magic Pie shipped with a 1.5" rim but my old 500w motor shipped with a 1.75" (or possibly larger, it certainly looks noticably bigger). Its something that would add little or no cost to GM but costs us alot locally to purchase a new rim and have it respoked.
Maxxis hookworms are a popular ebike tyre that are big and wide and absorb alot of the bumps, but at up to 2.5" in size I doubt they'd fit on a 1.5" rim.
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Discuss this... and don't say I don't care for my beloved forumers. ;)
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Discuss this... and don't say I don't care for my beloved forumers. ;)
Who said this?
Where?
Anyone?
:D
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Sweet. Is that an 18" rim ? Can it run normal tubes ?
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Sweet. Is that an 18" rim ? Can it run normal tubes ?
Looks like 48 x 2.50 on the sidewall, but I can't find any information on that particular tyre size, so I'm guessing it's 16" from scale measurements of the picture, but the rim doesn't look like it's suitable for V brakes, so I presume a disc, drum or band brake will be required.
The photo definitely shows a conventional valve sticking out, so it looks like a normal tube can be fitted.
16" rims (and possibly 18" rims as well) would need to be fitted with a solid, non-pneumatic tyre (http://www.amazon.com/dp/B000AO5MVS/ref=asc_df_B000AO5MVS946590?smid=A2TE9IQP68MWQU&tag=shopzilla_mp_1221-20&linkCode=asn&creative=380341&creativeASIN=B000AO5MVS) or solid inner tube (http://www.noflattires.net/cart.php?target=product&product_id=479&category_id=117) as there would be no way of fitting a valve.
Perhaps it was this very comment about the valve that persuaded GM into producing this rim, just just so they could prove me wrong. ;D
Alan
A man who never made a mistake never made anything.
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A man who never made a mistake never made anything.
Then that makes me a walking error.
:P
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I've just noticed this wheel on the GM website (http://www.goldenmotor.com/magicpie/magicpie.html), but I'm not convinced that the speed figures shown are correct:
(http://www.goldenmotor.com/hubmotors/hubmotor-imgs/MagicPie%2016in.jpg)
eBike Speed: 25kph/24V, 33kph/36V and 45kph/48V (Based on 26" rim, 80kg rider)
Assuming this is the same motor and runs at the same rpm as the 26" version, the speed will be approximately 17kph@24V, 21kph@36V and 28kph@48V for this 16" rim.
The speed figures shown on the picture would only be correct if it can spin 62.5% faster than the 26" pie! ::)
Yao, can you please clarify these speed figures?
Alan
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Dear All,
You might find it strange, however the 16" is made to hit that speed. The windings are different, lower torque but higher speed. Go check out the Tq figs for the 16" and you shall understand!
Chopper stingray fans anyone?
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Go check out the Tq figs for the 16" and you shall understand!
I've just had a quick search and couldn't find an obvious link on the site, but I did eventually find where the files for the 36V dynomometer test results were:
16" Magic Pie performance curve at 36V (http://www.goldenmotor.com/magicpie/16in%20MagicPie%20Performance%20Curve.pdf)
16" Magic Pie performance data at 36V (http://www.goldenmotor.com/magicpie/16in%20MagicPie%20Performance%20Data.pdf)
The speed figures shown on the picture would only be correct if it can spin 62.5% faster than the 26" pie! ::)
The 26" Pie wheel speed is 33.60kph@270rpm (max unloaded wheel speed)
The 16" Pie wheel speed is 37.44kph@480rpm (max unloaded wheel speed)
This means that the road speeds for the 16" Magic Pie could be even faster than the 26" version, as it can spin 77.7% faster!.
Alan
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Sounds like I want this motor instead of the one I ordered (MagicPie 'Classic') :). What is exactly the RPM limiting factor? I've been reading up on brushless motors a bit, but I'm not entirely sure yet. I figured it had to do with the controller, essentially with the max speed at which it can switch the succesive coils and feed them enough current with a steep enough rate, but since the windings are apparently different I'm again clueless..
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It seems confusing when they have two columns with (W) in it. What does the (r/min) column denote? I can't believe it's rpm, the numbers would make no sense. Anyone wish to translate the information?
These figures are obtained by testing the motor on a dynamometer, A device which gradually applies a progressively increasing test load onto the wheel, whilst measuring the wheel speed, torque, the power consumed and the power produced by the wheel.
This is why the rpm is high to start with and slowly decreases as the power and torque provided by the wheel increases.
The "W" on the left is the power produced by the motor in Watts.
The "W" on the right is the power consumed by the motor in Watts.
The Efficiency is calculated by dividing the power produced by the power used and then multiplying by 100 to give a percentage.
e.g. If a motor consumes 600W and only produces an output of 500W, the efficiency would be 500/600*100 = 83.34%
The r/min column shown is the actual rpm of the wheel measured during the varying test load.
Alan
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Dear All,
You might find it strange, however the 16" is made to hit that speed. The windings are different, lower torque but higher speed. Go check out the Tq figs for the 16" and you shall understand!
Chopper stingray fans anyone?
I have the electrc version of the sting Ray chopper...
I desperately NEED the 24" Magic Pie...
I would LOVE a 20" one ( but it would need to be a WIDE {4"} rim/tire cast would be awesome-- maybe I can special order one? )
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can I order 16" MagicPie Casted Wheel but instead of cast wheel a normal 26" bycycle wheel (with 16" MagicPie Casted Wheel motor) so I could go FASTER THAN 45 km/h ?
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Yes yes yes! That would be exactly the ticket! The 16 incher wrapped in a 'normal' bicycle wheel size (or just offered with flanges ready to accept spokes!) Come on GM, you already have the motor windings etc. figured out, just get rid of that cast rim and throw on some spokes :P
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I'm buying a folding bike with 20" wheels for some travel by train in 2010. I'd love to see the Magic Pie in a 20" wheel. The simplicity of it's design, with the controller housed in the wheel, would be even more ideal for a folding bike. I put an electric motor on my mountain bike this past summer and definitely will install an electric conversion kit on the new folder. I hope the Magic Pie will soon be available in 20" wheels because that's the motor I'd prefer to install.
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We really need the 20" and 24" models...
Is this possible and if so when would they he ready for sale
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I just wanted to say that we received our 16" MP today less than two weeks after payment with just 4 days shipping, including customs, from the factory in good order. It will be awhile before I can post about its intended use and how it performs but just wanted to say thanks to the Golden Motors team here for making just what we needed at just the right time ;D
Mabman
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Don't get too excited about the Magic Pie as you havn't got the antitheft wheel locking device to work yet, and as far as I know nobody has! I don't even believe it has been implimented in the "Magic Pie" although it is clearly documented on GM's website. My main reason for buying the "Magic Pie" was to protect me against theft as I have invested over €2000 on my bike.
Good luck,
Jim
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Anti theft devices only keep honest people honest. The anti theft option, even if not working as advertised, is not going to affect our needs at this time.
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Don't get too excited about the Magic Pie as you havn't got the antitheft wheel locking device to work yet, and as far as I know nobody has! I don't even believe it has been implimented in the "Magic Pie" although it is clearly documented on GM's website. My main reason for buying the "Magic Pie" was to protect me against theft as I have invested over €2000 on my bike.
Good luck,
Jim
wtf, 2000,-? on what
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Discuss this... and don't say I don't care for my beloved forumers. ;)
(http://goldenmotor.com/SMF/index.php?action=dlattach;topic=1430.0;attach=1408;image) (http://goldenmotor.com/SMF/index.php?action=dlattach;topic=1430.0;attach=1410;image) (http://www.arhservices.co.uk/GoldenMotor/Pie16FOffset.JPG) (http://www.arhservices.co.uk/GoldenMotor/Pie16ROffset.JPG)
I think that the 16" cast alloy rim looks really nice, but I was surprised to find out that it still suffers from the offset rim problem.
(About 7mm offset on the front and around 9mm on the rear.)
This could easily have been sorted if the rim had been offset to allow for the offset hub as shown in the attached diagrams below.
I realise it may not be cost effective to produce two different rims for the same size wheel, but if it had been designed with an offset 7mm, it could be used either way round to suit front or rear wheels.
This would have given a perfectly centred front rim, and a much reduced rear offset of 2mm instead of 9mm, which would be a lot easier to accept.
A front rim which is not correctly centred will have a noticeable affect on the steering, it will pull to the left under acceleration, and pull to the right during braking and I expect it will also upset the self centring castor action as well.
It should be relatively easy to incorporate the correct amount of offset into both the design and the manufacturing of a cast rim.
I would love to hear your comments on the subject of offset rims.
Alan
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Dear Alan,
We are going to create moulds for 20" cast rim for MagicPie since 20" rim is most popular for teenage bikes. We will adopt your suggestions to make 20" rim more centered.
But we like your and other bike riders advices on tire sizes for this 20" MagicPie. It is expensive to make new mould. So we want more feedbacks on 20" to mount most common available tires.
Thanks for your support.
Golden Motor
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I applaud the idea of a 20" cast rim and fully centered front wheel version. I would be in favour of maintaining the current 16" maximum rpm, thus increasing top speed due to larger circumference. Personally, I am partial to big tires such as the Schwalbe Big Apple for their ride comfort.
I must say I am not a conventional user, as I am not into the bicycles so much as into the electric vehicles. For a lightweight electric vehicle ('EV'), the Magic Pie is excellent. There is one additional feature though that I would greatly appreciate, and that I believe would be beneficial to have for GM if you wish to become a player in this market as well: reverse. I'm no expert on the electronics side, but I can imagine it only requires modification to the controller.
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There is one additional feature though that I would greatly appreciate, and that I believe would be beneficial to have for GM if you wish to become a player in this market as well: reverse. I'm no expert on the electronics side, but I can imagine it only requires modification to the controller.
If this is enabled, then it should also include a warning tone, like a truck/lorry, when reverse is selected so that you know not to go full throttle in reverse and/or have it limit the rpm when in reverse.
Muzza.
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I don't know how feasible this idea will be, but here goes anyway:
I propose an adapter ring could be cast out of lightweight alloy to enable the existing hubs to be adapted to enable all spoked wheels to have their rims centred correctly.
First, One of the spoke fixing flanges would need to be machined off the existing hub.
Then the cast adapter ring could be bolted on top of the side cover using longer bolts to secure both parts in one go.
This would effectively reposition the spoke flange so that they were both approximately centred within the axle fixings rather than being centred on an offset hub.
Front and rear hubs would need the adapter to be fitted on different sides, but it should be possible to use the same adapter for both front and rear wheels as the spokes should be able to compensate for the slight differences.
The assembly could then be repainted as required to blend in the machined surface and the newly fitted adapter ring etc. prior to the assembly of the wheel, which could then be built with the rim perfectly centred. (and hopefully concentric as well ;))
This modification would mean that only one side cover could be removed easily for access to the motor and controller if required, but I don't see that would be a real problem.
I've tried to show exactly what I mean with the following animation:
(http://goldenmotor.com/SMF/index.php?action=dlattach;topic=1430.0;attach=1572;image)
it would be nice to know what the guys at GM think to my suggestion. :)
Alan
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Alan!
You take this out of my mind! I swear I have it drawn in a notebook!
But I see it as a (good, but) temporary solution, for long therm they need to have a new design for this component.
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There is one additional feature though that I would greatly appreciate, and that I believe would be beneficial to have for GM if you wish to become a player in this market as well: reverse. I'm no expert on the electronics side, but I can imagine it only requires modification to the controller.
If this is enabled, then it should also include a warning tone, like a truck/lorry, when reverse is selected so that you know not to go full throttle in reverse and/or have it limit the rpm when in reverse.
Muzza.
I definitely agree with the rpm limit in reverse, not so sure about the horn though ;) (never needed one in the car :P). On the other hand, if we keep the rpm the same as in forward 'gear', since the hub motor should offer us this possibility, we can do reverse races like with the old DAF variomatic cars that went equally fast in reverse as in forward speed :)
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I definetly agree with Alan that something should be done about the off centre wheel.
The Idear and animation looks very good, to fix the current pies.
The next phase however would be to learn from this first pie and alter the fabrication proces.
Would be a shame to pruduce such a nice motor with some minor design flaws in big numbers.
Best regards,
Jerry.
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In a 20" cast wheel, I would need something that would fit my OCC chopper rear..
The tire in the back is normally a 4" tire so I'm guessing that the 20" pie wouldn't work for me :(
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Hi all,
I built a 20inch folder using a front wheel 'Nano' motor, with a 9AH Li battery. Done 1000 miles so far...brilliant (17 miles on the flat without pedalling at 16mph). Incidentally keeping the battery and charging at zero degrees in the garage has reduced the capacity significantly...this was recovered by keeping and charg[/img]ing the battery inside :)
I'm starting a new project based on a Trice Q tadpole trike, (20" wheels) and need a rear wheel motor, my choice at the moment is the 48V 1000W, but I'd prefer a Magic Pie as it would be neater. Roll on the 20" Magic Pie for summer... 8)
PS I don't think it is stated, but these high power motors should have a torque bar provided, otherwise I'll have to fabricate one...
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some china suppliers have motor hub wheel in 2000 w 3000 w 4000w and 5000w difrent size and speed 60 to 150 km ph . verry nice design.good price