I'm from a place where finding a standardized size for tyres bigger than 26 inches is mostly a hassle, to say the least..
But sadly (or not) I have a bike that I've been riding for a while now and have used it enough to wear out the tyres. The stock tyres on the bike were 700×35c. The rims on the bike are, as I mentioned above, 21-622 ETRTO. Now, the tyres that are bigger than 26' that are somewhat widely available around here and are ETRTO 635mm tyres. The confusion looms because, well, both of them are referred to as 28' tyres by more than just a handful of people..
It's simply used for commute on roads I won't particularly describe as best, and I avoid most bad potholes, if that helps.
So, if I'm unable to find 700c or 622mm tyres, it is safe for me to be using the 40-635 tyres without changing the whole wheel? I mean, I can probably find a tire that has a smaller width but a smaller diameter tyre seems to be hard to find around here..