What ever rim/tyre combination you have .. you're certain to run into the situation of having to order it in .. so the size of the tyre/rim matter less.
Suggest you estimate on your tip where teh tyre will expire .. find a phone number for a bike shop a little ways before the tyre expires - ring them up and order in a tyre .. should have this orgainised say a week or two before you get there ..
If you cannot find anybike shop .. then ring the previous bike shop and have them send on on to you a week or two infront..
Only in some places will you have to carry a tyre with you..
Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S