35x12.50R20 is 0.10" shorter than 295/65R20, a −0.28% change in diameter, inside the 3% range most shops treat as a safe swap.
Ground clearance changes by 0.05" (half the diameter change), and the tire needs 0.05" less room above it.
35x12.50R20 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 20" wheel; the sidewall is 0.05" shorter on 35x12.50R20.
Details: 295/65R20 in inches · 35x12.50R20 in inches · change sizes in the calculator