im about to change my rims and wheels from 16" to 18".i saw a set of 18" rims with a set of runflats(rsc rft) bridgestone for 1300$ (genuine bmw used rims). i beleive the rims are in good conditions but dunno about the used tires.

how do i know if the tires are good.is there a mark i should look @, the threads perhaps.how are the threards supposed to look like,a date on the tire perhaps?

thx a lot for all help and replies.