I’ve inflated 2.25in NNs without too much issue. It is worth spending 5 minutes extra getting setup first or you’ll just get annoyed because it won’t quite inflate.
A few pointers that might help:-
– Having the tyre warm (i.e not straight out of a frozen garage) will mean it is more pliable and slide into place better
– A little washing up liquid on the beads will help you seat the tyre if it is tight to get on
– Give it a quick shot with a track pump if you want, but if you want to save lots of expletives, go for a Co2 cartridge if it doesn’t work after the first few attempts with the track pump
– Gently hold the tyres near the valve so that the air has a fighting chance of staying in the tyre rather than disappearing straight out of the sidewall gap by the valve
– If going for Co2, I’d try to inflate the tyre (wear gloves!) without any sealant in and the valve core out, then gently let the air out but don’t break the sidewall seal and put the sealant in through valve
– Once you had inflated it once, as long as you don’t dislodge the sidewalls from the rim, you should get it reinflated fairly easily (with a track pump)
Having done a good few wheels and tyres over the years, I now don’t bother too much with the track pump. If it isn’t going to work after one or two attempts, I’ve decided it is worth spending a small amount on the co2 cartridges (cheap from specialists online) to save a lot of agro.
Best of luck! At least you have Stans rims which are much easier to get tyres inflated on than ghetto tubeless setups.