20" unis and tyres

[aracer]

Am thinking of getting a new uni to replace my 20" beginners one, as I'm sure I'm doing more with that than it was designed for, and would like to do some bigger jumps/drops. It's also been making horrible creaking noises when I've been learning to idle - will hopefully replace the bearings, but not sure if that's going to fix it. Keen to still have a uni that size, as I find it a lot easier to learn stuff on.

Was thinking of getting a 19" trials one as the most versatile, but then wondering about tyre choice - I have a slick tyre on my current one, which I can pump up hard to make turning easier, handy for stuff like learning to idle. However all the 19" tyres seem to be knobblies. The alternative would be a robust 20", eg http://www.unicycle.uk.com/unicycles...ycle-blue.html as I see you can now get a big volume trials tyre in that size for when I want that.

So the question is, is there actually any disadvantage to a knobbly 19" trials tyre - am I worrying about nothing, and would it not actually be a problem? Don't really care much about how well it rolls as I have a 26" muni and a road 29er (when I rebuild the wheel!) for distance riding - if handling for learning tight turns, idling etc. is just as good (if I pump it up hard?) then not an issue. Though I guess I've just about sussed idling now, so maybe it's not important at all. Any advice welcome.