What should I look for in a mountain bike for doing BMX-style balancing tricks? When I was a kid I started learning to ride around on my back wheel and it was really difficult.  Then I tried doing it on a crappy CCM mountain bike we had (rather than my nice Gary Fisher Piranha) and it was much easier!  I could ride around balanced on the back wheel for a full minute, and was able to do other tricks more easily as well.

For reasons unknown to me, the CCM was much easier to balance in that position.  I'd like to fool around on my bike and learn some more tricks, but if I buy a new one it will be a mountain bike.  Which leads to my question: What do I need to look for in a mountain bike if I want to be able to do this stuff?  I can imagine it's related to the following, but I don't know exactly how:


Weight
Size
Shape?
Weight distribution
Other?


The CCM was heavier and taller, if that helps.
You want a very low stand over height, short chainstays, steep headangle, and little to no suspension.  If you still want to use it for general mountain biking stuff, then look at street or dirt jump bikes, rather than trials.