GoldenMotor.com Forum
General Category => Magic Pie & Smart Pie Discussions => Topic started by: GoldenMotor on January 25, 2016, 06:44:34 AM
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(http://www.goldenmotor.com/e-Bike-DIY/MagicPie-edge-1.jpg)
(http://www.goldenmotor.com/e-Bike-DIY/MagicPie-edge-2.jpg)
(http://www.goldenmotor.com/e-Bike-DIY/MagicPie-edge-3.jpg)
(http://www.goldenmotor.com/e-Bike-DIY/MagicPie-edge-4.jpg)
(http://goldenmotor.com/e-Bike-DIY/mpgallery/images/0153.jpg)
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Interesting More data please : Width ? 135 mm ? How is the wheel centered ? Price ?
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How does it support a 7 speed freewheel when it has a built in freehub? I have had to replace several complete mountain bike wheels because the part of the freehub within the hub has worn out, that means replacing your entire motor if this part wears, this is a bad design IMO. More info please!
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How does it support a 7 speed freewheel when it has a built in freehub?
Basically it doesn't. There are two different versions of the Magic Pie Edge rear wheel, one for freewheels and the other for cassettes.
The cassette version incorporates a threaded freehub which screws into the side casing, whereas the freewheel version has a threaded boss to accept the screw on freewheel, just like the earlier Magic/Smart Pies.
Replacing a worn out freehub (or replacing the internal bearings) would require a special tool to undo it, although it should be possible to use a 12mm Allen key instead but the stator and axle assembly would need to be completely removed from the opposite side of the hub to allow the Allen key to be inserted.
Alan
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Thanks Alan:
In my experience with pedal only bikes, as I mentioned before I find the ring inside the hub is often what wears out not the free hub body itself, rendering the entire hub garbage as it's a steel piece cast inside an aluminum hub. Glad to see GM thought ahead and made the entire unit replaceable (even if it is a pita to change). I could see the Smart Pie being dropped as this motor covers all the bases for a smaller size/output motor. ;)
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OCD,
In most cases, the freewheel removal only requires a Park Tool FRS 1.2 freewheel removal tool that must be modified to accept the larger diameter axle bolt -- the hole in the center is essentially bored out to be slightly larger than the diameter of the hub motor axle.
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Replacing a worn out freehub (or replacing the internal bearings) would require a special tool to undo it, although it should be possible to use a 12mm Allen key instead but the stator and axle assembly would need to be completely removed from the opposite side of the hub to allow the Allen key to be inserted.
Hopefully this diagram showing a screw-in freehub unit will make it a bit easier to understand:
(http://www.arhservices.co.uk/GoldenMotor/Magic%20Pie%20Edge/Freehub%20removal_zpsyrohh2jv.JPG)
To access the freewheel pawls and springs without removing the entire freehub unit or the axle/stator assembly would require a tool like this:
(https://i.imgur.com/hvLZlRx.png) (http://www.superbiketool.com/prod4.asp?menu=3&cid=1&pid=430)
The half inch square drive on the end of the tool (not shown in the diagram) should slide easily over the 12mm axle, and you would then need to use a large 24mm spanner to undo the bearing cone:
(https://i.imgur.com/4M1C2hY.png)
Please be aware that the GM freehub may differ slightly from the ones shown above. ;)
Alan
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Now it makes sense to me. The pawls unscrew from the side cover, the outer toothed ring is on the free hub cassette carrier. In a regular rear hub the toothed ring is cast into the hub and the pawls come off with the cassette carrier. I assume with the freewheel style the inner threaded piece has the freewheel threads. It's a well thought out design. :)