Magic Pie Edge fitment and info?

[Jbwiden]

Looking to buy a Magic Pie Edge 8-10 cassette, but have a few questions.

I have a hard tail mountain bike (19" Giant Rainier ~2005) that I intend to convert, it is an aluminium frame and I would put the motor on the rear. The inner spacing between the dropouts is 135mm and it has a 9 speed cassette currently. I believe I should be using at least one torque arm. Is there any reason to suspect fitment issues with the kit? I see the kit is designed for 135mm spacing though would like to confirm my configuration with the 9 speed cassette as I don't want to bend the aluminium frame.

I also believe that maximum speed is likely around 28MPH (45KPH) on flat ground average sized rider using a 48Volt pack, is this a reasonable expectation?

[Bikemad]

Hi andto the forum.

I still have a pre-production cassette version of the Magic Pie Edge which I received back in September 2015, which has still not been installed onto a bike because I was not happy with the original fixing method.

My proposed solution was to extend the thread on the axle to allow an additional nut to be inserted that would withstand the compression forces as the axle nuts were tightened.

GM decided to simply place an additional 7mm thick nut onto the existing axle, but this means that the dropouts need to be spread slightly to accommodate the increased internal axle width (142mm instead of 135mm).

It is possible that the axle may have been modified on more recent versions of the Magic Pie Edge to reduce it to the standard 135mm axle width, but in reality, I don't suppose that it will have been changed.
Hopefully, someone with a recent version will be able to confirm the current overall internal axle width.

Regarding torque arms, I strongly recommend that two torque arms should be used with the 12mm axle used on the Magic Pie Edge. However, I am still hoping to modify my existing axle using a standard 10mm diameter thread (without the machined flats) employing a single custom torque arm using a 12mm square drive to effectively transmit all of the torsional axle forces directly to the frame:





This would ensure that the axle would fit perfectly into most standard 10mm diameter dropouts without the need for any additional filing, and it may also be possible to further modify the axle to allow a quick release skewer type fixing to be used in conjunction with the custom torque arm:





Check out this post for further information relating to the Magic Pie Edge axle.

28mph (45km/h) should be achievable on suitable flat surface with a 26" road tyre (provided there is no headwind).

Alan
 

[Jbwiden]

Alan,

Thanks for the detailed reply!

The compromises to get the cassette version to work may be more than I am willing to bear.

The design is unfortunate, your suggestion to thread the axle more seems quite reasonable and hopefully was implemented. If it was not could an end user cut new thread with a die on the axle themselves, any concerns there? Also, might consider a thinner jam nut, but not seeing much below 6mm for the m12 1.25

>Hopefully, someone with a recent version will be able to confirm the current overall internal axle width.
+1, I have not been able to find anybody who has shown the assembly in enough detail to see.

>Regarding torque arms, I strongly recommend that two torque arms should be used with the 12mm axle used on the Magic Pie Edge.
hadn't realized that it was 12mm, with that I can see that two are needed. Even then it gets me a bit nervous.

[Bikemad]

Could an end user cut new thread with a die on the axle themselves, any concerns there?

The steel axle is probably soft enough to allow a decent die to be used, but the freehub unit would need to be removed to allow the thread to be extended an additional 7mm along the axle to accommodate the 7mm thick nut.

 

Hopefully the flats on the axle would not cause the die to run out of true on the unthreaded portion of the axle.



Alan
 

[Jbwiden]

I have been mulling it over and think a better solution is just to get the freewheel version. Swap the shifter to the proper speed for the chosen freeweel gear count. I'm leaning towards a 7 speed to ensure proper fit within dropouts but would prefer 8 to keep it closer to the stock 9 speed cassette.

[Tommycat]

Now I know your talking about the MP Edge motor. And I don't know how different it is. But I have the Magic Pie V5 which also has a 135mm dropout
requirement. And using a 7 gear freewheel necessitated spreading the dropouts about 5mm. (135mm factory width)  As the gears extended over the threads a bit. No problem for me with my steel frame. And adding a spacer washer worked well. But I also thought that the two small shoulders where a little underwelming against 50 plus foot pounds of axle nut torque. (Now why didn't I use a jam nut instead... ) Likely not all freewheels have the same width... I appreciate your concern and desire to find some accurate dimensions!

+1 on the dual torque arms!


Regards,

T.C.

[Jbwiden]

I found this video from Golden Motor Canada that shows a specific 7 speed working with an edge that appears to require no spreading. With the 8 its close, maybe one extra spacer.

https://www.youtube.com/watch?v=KPk7SqgiuV8&feature=youtu.be&t=236

[Tommycat]

The motor must be narrower...good!  But I read where 7 is the max.

Found a picture of it with dimensions on this website. See the photo gallery.

https://www.miromax.lt/en/c-26/c-27/product-589-magic_pie_edge_5_conversion_kit_without_a_rim__bonus

On closer inspection, it's of a cassette type...may still help.

[Bikemad]

>Hopefully, someone with a recent version will be able to confirm the current overall internal axle width.
+1, I have not been able to find anybody who has shown the assembly in enough detail to see.

The above photo from the Miromax website clearly shows the nut outside of the freehub unit rather than , if the axle had been threaded further, the nut would have threaded on further and would end up being partially recessed into end of the freehub unit to produce the correct 135mm internal axle width.

Alan
 

[GM Canada]

Hi andto the forum.

I still have a pre-production cassette version of the Magic Pie Edge which I received back in September 2015, which has still not been installed onto a bike because I was not happy with the original fixing method.

My proposed solution was to extend the thread on the axle to allow an additional nut to be inserted that would withstand the compression forces as the axle nuts were tightened.

GM decided to simply place an additional 7mm thick nut onto the existing axle, but this means that the dropouts need to be spread slightly to accommodate the increased internal axle width (142mm instead of 135mm).

It is possible that the axle may have been modified on more recent versions of the Magic Pie Edge to reduce it to the standard 135mm axle width, but in reality, I don't suppose that it will have been changed.
Hopefully, someone with a recent version will be able to confirm the current overall internal axle width.

I have actually looked into this. In my experiments, the Edge cassette version fit 135mm dropout fine if I left out the washer next to the 7mm nut. I experimented with my mountain bike which appears to have a sloppy 135mm fit. Somewhat flexible but rests at 135mm. I quite easily got it to drop into the frame with one hand so it cant be that difficult.



I do actually remember these conversations when the edge was being developed. But I have never had a complaint about them before not fitting and we have sold a lot of them. Actually, the edge is by far the most easily mountable motor due to its size and shape. Now with the cassette version even more so. But I was recently sent back a kit because it would not fit for someone. I got for it back and this is the one I experimented with in the video. It seems to work well for me. 

Here is a quick video thrown together Fitting the Cassette version of the edge

I see some other pictures uploaded showing motors with the washer in what appears to be about the same position as mine. But in practical use, it doesn't seem to be much of an issue.  People have been stretching frames out on bikes for years to get 7 and even 8 speed freewheels on their bikes.  I did it years ago myself with an 8 speed freewheel on my townie in this video.

Mounting an 8 speed freewheel on a Magic Pie

If anyone is stretching a frame a bit to use a 10 speed cassette like we have been to fitt the 7-8 speed freewheels,  I would assume most people would find that acceptable. I was actually surprised about this considering how many we have sold and never having heard of this before. People must either be eliminating the washer like I have or just pulled it open enough to drop in. This has to be easier then "re-inventing the wheel"

Gary