I have only one data point for you...
2005 Honda Civic
factory 14x5.5 steel wheels
OEM Dunlop SP20FE tires 185 70 R14 set to 44psi
combined weight = 30.5 lbs
you can also find tire weights (I'll assume they're approximate) on tirerack.com (look up a specific tire and then go to the spec section).
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