I’m purchasing the nimbus x longneck frame soon and I’m not sure which sized seat tube to get the frame in, 300mm or 400mm. I’m 5’ 7" with an inseam of about 31-32 as UDC instructs you to measure it. I want as little seat post visible as possible so I’m afraid going with the smaller frame it wont be quite high enough for my tastes. Even though the minimum recommended inseam for the 400mm seat tube is 33 should I be able to comfortably fit? If not is it difficult to cut the frame down to fit as closely as possible? Remember, I’m not talking seat post, I’m talking the frame. http://www.unicycle.com/shopping/shopexd.asp?id=849 Any help would be appreciated, I’d like to try and order soon so it can be in before my vacation next week is over 
take the uni you normally ride and measure the distance from the crown of the frame to the bottom of the saddle and you’ll have a pretty good idea of what you need.
i’ve also been thinking about getting this frame, but the top doesn’t look quite wide enough to give good foot support.
Well I dont have a 20" right now, im ordering a whole setup so I dont think that will work, but that was a very good idea, hmm, maybe if I just add 4 inches to whatever I get?
I have a 31" floor to crotch inseam, and I have the 300mm version of that frame with 125mm cranks. There’s about 2.5" (63.5mm) of seat post that sticks up above the clamp. If I wasn’t doing seat out stuff and I had 110mm cranks, I might be able to barely fit a 400mm, but then I wouldn’t have as much flexibility in setup. I’m guessing you could cut down the 400mm with the proper tools if you had to.
Also, it has a Torker LX saddle on it, since saddle thickness matters too.
I don’t think you’d want to cut it down, you’d just create a spot for it to rust, and you’d have to cut a notch for the seat clamp. If my calculations/estimations are correct, figuring for 5" cranks, and 12" for the wheel + crown, you’re left with about 330mm between the crown and the top of the seat, so I would go with the 300.
Thanks everyone, so 300mm it is. I’m ordering my new uni now, yay. the 20" Nimbux X with the frame swapped out for the Nimbus Longneck, tire swapped out for the white primo the wall 2.1" tire and silver primo viking seat post clamp.
whats the point of an extra long neck??
I believe the long neck keeps little bits like the seat post clamp out of the way of your feet when you’re freestylin’. It also looks a lot sleeker, I think.