35x12.50R18 is 0.74" taller than 295/70R18, a +2.16% change in diameter, inside the 3% range most shops treat as a safe swap.
Ground clearance changes by 0.37" (half the diameter change), and the tire needs 0.37" more room above it.
35x12.50R18 is 0.89" wider. On the same wheel offset about half of that, 0.44", moves toward the suspension and half toward the fender.
Both fit a 18" wheel; the sidewall is 0.37" taller on 35x12.50R18.
Details: 295/70R18 in inches · 35x12.50R18 in inches · change sizes in the calculator