I just installed 15 x 7 with 4 3/16 BS with 245/60/15 on the rear of a 70 dart completely stock. Have about 3/4 inch to spring and 1/4 to wheel lip. If I would roll the lip, could have went with 255/60/15. Also depends on rear ride height , if you use air shocks or anything that raises the height it helps to get a wider tire under there. Hope this helps.