I am really interested in learning crankflips and Unispins.I can already do 180 jump mounts and zeroplants but when I got to the final stage My feet wouldnt come off the pedals.I was hoping if someone else has had this problem and if and how they over came it. Videos appreciated. Thanks in advance.
I recently just learned to unispin, (dont know what tell you for crankflips) but basically try holding on to a fence or something you can grab the top of thats a bit taller than you when you are you are riding. Then as you jump push down on the seat (this took awhile for me to get the hang of my self), try pulling up alittle with your arm grabbing the fence. The only problem with this is that you will have to do a one handed Unispin(which looks cooler in my opinion). Now this the way I learned but it is not THE way
Hope you get it:)
Oh also I Dont know if you have shin pads, but they will make you much more confident because if i wasnt wearing shin pads i wouldnt be able to see my legs 
+1
When I learn 180 unispins I smashed my shins so many times sometimes it was that hard it still bruced with the shinpads.
I was trying that yesterday and i cant get the height i need. What do you guys suggest, just practice because this is really annoying.
It might be your tire. Is it a trials tire or a flatland tire, Trials tires have great air volume and are nice and bouncy. If you have such a tire already it might be the amount of air in it. You may have to much which doesn’t let you compress the tire(no spring) or to little where your hitting your
rim. Also I don’t know if you just learned hopping but that could be the case
If none of this helped I don’t know what to tell you
Maybe post of video of your progess and we might be able to help you out a bit more. 
I’ll try it’s raining where i am so I’ll try to due it tommorrow
ya i cant get a hold of working camera