Can 20570r15 be substituted for 215 70 r14?

No, a 205/70R15 tire cannot be directly substituted for a 215/70R14 tire. The first number represents the tire's width in millimeters, which is different between the two sizes. The second number indicates the aspect ratio, which remains the same, but the last number signifies the rim diameter; a 15-inch rim cannot fit on a 14-inch rim. Therefore, you would need to stay within the same rim size and specifications for a proper fit.