I picked out some M12 XC tires based on a recommendation from a friend. I got a 130/80x18 rear, and it is a little smaller than other tires with the same numerical size. Seems perfect for this, not too much tire.
On thing I did was to put both tires in with Bib Mousse, as I hate changing tires. I will not be doing extended slab on this, so they should hold up well.
On gearing, in the case of the little XR, some people say that you should gear them up
. Stock gearing is 13/48, or 3.69. I looked at some application charts, and decided to go with a 13/45 (3.46) set from Supersprox:
gets blue Loctitite, especially sprocket bolts:
Sprocket w/XRs Only Guard:
Once I added the XRs only guard, the stock cover would no longer fit. But I did some Dremeling on it:
cleaned it up with a wire wheel:
And got it to fit. I now have a stronger case protector, and it looks like stock: