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Just take a measurement of the stud length and one of the lug nuts and try any automotive supply store. I'd be re-using the old rims and just mounting new tire. Just do a good cleaning of the bead area of the rim before mounting the new tires.
Should you decide to replace the rim, you'll need the same diameter, width and bolt pattern/circle. To find the bolt circle of the lug pattern, measure the lug centerline to lug centerline across the rim center.
Nights camped in 2013 - 55, 2014 - 105, 2015 - 63