I’m wondering, how do you get the cranks off a nimbus axel? so if you could help me out that would be much appreciated. 
Dan
I haven’t read the whole thing, but check out Obie’s article in the Articles forum,
http://unicyclist.com/forums/showthread.php?s=&threadid=38277
might have what you’re looking for.
PS you ought to post this in the RSU forum.
I’m assuming your Nimbus has the regular square taper cranks (cotterless).
You use a crank puller. You can buy them at any bike shop.
I would recommend one similar to the Park CWP-6. You’ll need a crescent wrench too with that style of crank puller. There is also a style of crank puller like the Park CCP-2 that have a built in handle so you won’t need a separate crescent wrench. But those types of crank pullers don’t work as well for unicycle because the handle is too long. Unicycle cranks tend to be shorter than bike cranks. The pedal ends up getting in the way and prevents you from spinning the handle all the way around 360 degrees. You end up needing to take the pedal off first so you can operate the crank puller. Not very convenient. The style of crank puller that requires a separate crescent wrench doesn’t have that problem.
Anyways, Unicycle.com sells crank pullers and so does any bike shop.
The links at Park Tool have pictures that show the tools in use and brief explanations of how to use them.