Wheel and tyre size

This must be a really old topic but having just gone solo for first time and wanting to buy the ideal ike what do people recommend for a 69 year old much wanting to start learning properly.(I imagine as with flying you only start really learning after your first solo)

there is a big difference between the uni you learn on and afterwards your “usual” uni because once you’ve learned you may prefer fairly different practices.
learning on a (rather wide) 20" is a good thing to start with… once you feel confident enough you can buy some other steed for your stable (I own 7! but I prefer Muni because I like unicycling in the woods; other “old geezers on one wheel” prefer a big wheel for the road … so it’s up to you).

I agree, 20" is the easiest wheel size to learn on. At your age it is harder to learn than when you’re younger, though still certainly doable. So, get a 20".

Tips for beginners and a spreadsheet to estimate how long it would take you to learn (includes age and other factors) can be found through http://www.xs4all.nl/~klaasbil/uni_beginners.htm