Yes, rims can generally fit a tire that is +/- ~1 inch (25.4mm) the width of the rim safely, some people stretch this to ~1.5-2 inches but ill stick with the "safe" tires. So ill break it down... Rim Width::Max Tire/Perfect Fit/Min Tire 4::76.2/101.6/127 5::101.6/127/152.4 6::127/152.4/177.8 7::152.4/177.8/203.2 8::177.8/203.2/228.6 9::203.2/228.6/254 10::228.6/254/279.4 11::254/279.4/304.8 12::279.4/304.8/330.2 13::304.8/330.2/355.6 14::330.2/355.6/381 15::355.6/381/405.4 Between 11 and 15+ are generally considered race car tires and will RARELY be found on production cars under $80,000 (with a few exceptions). Hope this helps.
It does not use the same rims. You must run a wider rim to run the wider tires.
It is safe to put 33x12.5r15 tires on 15x8 rims because the rim will still maintain a secure seal. The wider tires provide additional traction and contact with the road.
Short answer, no. The rim is physically wider on the 18.4 than the 15.5 rim
No. It is very dangerous to attempt to put the wrong tires on a rim.
No.No.
No you can not.
No.
NO, that is very dangerous.
No.
NO ! -Tires must always go on the correct rim.
Yes, both those will fit same rim
Yes, just be sure rim is same size as the ones tire is being mounted to.