Questions about BMX conversion

[Bennicus]

Hi all,
Just joined because I'm thinking about trying a conversion on a BMX but have a couple of questions:

Rims: Can I use my own rims, or are the only options for 20 inch wheels the cast ones?  It's not very clear on the ordering page, but it looks like the Super Pie is smaller and maybe not cast in the 20" version, so what length spokes would I need to fit that?  What about the Magic Pie Edge, is the 20" version of that also cast?

Tyres: Sounds like the cast 20" rims are wider than usual BMX rims, which is one of the reasons I'm asking about using my own rims, otherwise buying tyres might be a pain.  Got any advice in this regard, am I worrying over nothing?

Front or rear: All the examples I've seen of rear mounting are with a fairly hefty cassette, would it work with a single fixed ratio sprocket?  Would I need to add extra spacers?  If I mount on the front it might be better for weight balance (battery at the back), but will the cables get in the way?


Cheers all
Ben

[Bikemad]

Hi Ben andto the forum.

The Smart Pie comes with a conventional laced rim in the 20" version so tyres should not be a problem.
The GM rim is probably a lot narrower than your BMX rims but can still accept reasonably wide tyres.
I rebuilt the front wheel of my wheelie machine using a GM 20" rim as I wanted the front and rear wheels to match.



Even though the rims are less than an inch wide, it easily accommodated a 26" x 2.30" tyre on the rear:



And a 20" x 1.95" tyre on the front:



Unfortunately it is impossible to provide accurate spoke lengths for a specific 20" rim without knowing the Effective Rim Diameter (ERD) of the rim, the motor flange diameter, spoke pattern (radial, crossed or leading/trailing etc.) and several other requirements.
Check out the spoke calculator at ebikes.ca for more details.

What about the Magic Pie Edge, is the 20" version of that also cast?

Gary appears to have already answered this question in the other thread that you posted in:

The 20 inch Edge is spoked. AT least for now. I have some arriving this week. I should be able to upload a picture then.

Gary

A single speed thread on freewheel unit can be used:



If you are using normal width tyes, then a spacer should not be required.

Alan
 

[Bennicus]

Very interesting thanks!  My main concern with the spokes is I'll need to find pretty short ones, but I would like to be able to use whatever rims I choose.  Being a BMX, and with the extra weight and torque of the Magic Pie, I figure I'll need some pretty sturdy ones (rims & spokes).  The cast option sounds pretty robust, but I just don't like the appearance that much