stock tires 31's? sorry if its dumb one

[jasonroman]

well i have 82long bed. riding with 17in rims. tires are costing me money. id like to put some stock or ralley wheels on my truck to cut down on cost of tires. my rims aint in the best shape so no sense spending money on tires. anyway. i found a guy in jersey that has 4 15in ralley wheels with tires. not sure the exact size of tires. but guy said 31's. he sent me pics and they dont seem that big.
but, my trucks lowered. so my brother in law says they def wont fit. pics dont look like they are monster truck tires. and for price, id get 4 tires with rims for less then what im gonna pay for 2.
dudes an hour and a half away, so id rather not take a drive if tires wont fit.
he has an 80 sumthing c10. 2x like mine.