Does anyone know what size C clip is necessary to attach the dahon magnet to the bike? I actually have the magnet piece, but I dont know if the measurement is supposed to be the diameter of the post? or the diameter of the recessed region

Does anyone know where I could order it?

thanks

Not sure what you are asking here. There is two magnets to hold it together and thay are atatched to the bike from the factory. If you are trying to atatch them to a bike that is not made to use them we need pix and you neeed to explain more.

There should ne plenty pix on the net and maybe also videos on Youtube.

You can buy the entire Magnetix assembly from Thor (thorusa.com) and it is not expensive.

When I bought my bike, they installed the front wheel part of the magnetix assembly, and left out the back wheel part. I went back to the shop, and they gave me the magnet part + spring . They said I just needed a C-clip to install it, so I figured I could take care of it. But now I can't find the c-clip anywhere

Thanks

Sounds more than strange to me. If it is a "just" then why did the shop not do it themselves? This is the magnets: https://www.evanscycles.com/products/...t-set-ec047416 . this should be all you need. The rest is part of the frame (welded to the frame).
Is there a way you can give us some pix? I can not reach my dahon at the moment so I can not try to guess what is the problem. What Dahon is it you bought? New or second hand?

If I go back to the store I'm sure they'll install it for me - I might do that. I have the magnet, and the spring. There is a larger round part in the photo, which is what holds the magnet into the frame - that's the part i'm missing.