235/60R15 is 1.30" shorter than 225/70R15, a −4.74% change in diameter. That is more than the 3% many tire shops use as a limit, so plan on recalibrating the speedometer and checking ABS and stability control.
Ground clearance changes by 0.65" (half the diameter change), and the tire needs 0.65" less room above it.
235/60R15 is 0.39" wider. On the same wheel offset about half of that, 0.20", moves toward the suspension and half toward the fender.
Both fit a 15" wheel; the sidewall is 0.65" shorter on 235/60R15.
Details: 225/70R15 in inches · 235/60R15 in inches · change sizes in the calculator