Tyre sizes for 9" 20s?

[tintin]

Well, maybe I was lucky - or maybe my luck will run out when taking them off in springtime - but these dodgy centres went on with little fuss.

They're certainly not as slick or an instant snug fit as the real thing, but no heating, trimming or real forcing was required - although for 2 of the 4 rims I did have to "reposition" one of the set of 6 sprung pins to inside (rather than outside..) the retaining ring. That seemed to make them slot in more easily, but it may also mean that they're slightly more likely to fall off, though they all seem pretty secure.

Time will tell, and it's not like I'll be using Herman as my daily driver/for long trips during the winter, so hopefully they'll be jus' fine