Purchased 4 18" used rims off a 21 Explorer from Fenix Auto Parts in Canton Ohio. They shipped them to their location in Belleville Michigan for me (much closer), and I picked them up yesterday. I bought these for snow tires. 18" snow tires are close to half the cost of 21", plus you get better traction in snow with the taller side walls. Put one of the the rims on front and rear today to confirm fit, and there is no interference to the calipers. Looks to be about 3/4" clearance.
Thanks to 2020FordRaptor for the advice on this.
I think I am going with Michelin X-Ice instead of Blizzaks. They are very comparable when new, but the Blizzaks wear faster than the X-Ice, and the X-Ice have better traction when worn. Just waiting for them to go on sale at Costco.
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