295/70R18 is 0.55" taller than 285/70R18, a +1.64% change in diameter, inside the 3% range most shops treat as a safe swap.
Ground clearance changes by 0.28" (half the diameter change), and the tire needs 0.28" more room above it.
295/70R18 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 18" wheel; the sidewall is 0.28" taller on 295/70R18.
Details: 285/70R18 in inches · 295/70R18 in inches · change sizes in the calculator