315/70R17 vs 35x12.50R17

35x12.50R17 is 0.64 in (16.2 mm) taller than 315/70R17, a +1.86% diameter difference. With the speedometer set for 315/70R17, an indicated 60 mph is 61.1 mph on 35x12.50R17.

Is this a safe swap?

Diameter difference +1.86%: within the ±3% guideline

By overall diameter alone, 35x12.50R17 falls inside the ±3% range commonly used as a guideline when replacing 315/70R17. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

315/70R17 vs 35x12.50R17 differences
Measurement	315/70R17	35x12.50R17	Difference	% diff
Overall diameter	34.36 in (872.8 mm)	35.00 in (889.0 mm)	+0.64 in (+16.2 mm)	+1.86%
Sidewall height	8.68 in (220.5 mm)	9.00 in (228.6 mm)	+0.32 in (+8.1 mm)	+3.67%
Section width	12.40 in (315.0 mm)	12.50 in (317.5 mm)	+0.10 in (+2.5 mm)	+0.79%
Circumference	107.95 in (2,742.0 mm)	109.96 in (2,792.9 mm)	+2.00 in (+50.9 mm)	+1.86%
Revolutions per mile	587	576	−11	−1.82%

True speed with the speedometer calibrated for 315/70R17
Indicated	Actual on 315/70R17	Actual on 35x12.50R17	Difference
30 mph	30.0 mph	30.6 mph	+0.6 mph
60 mph	60.0 mph	61.1 mph	+1.1 mph
75 mph	75.0 mph	76.4 mph	+1.4 mph

Ride-height change: 35x12.50R17 raises the vehicle by 0.32 in (8.1 mm) at the axle (half the +16.2 mm diameter difference).

35x12.50R17 is 0.64 in taller than 315/70R17 and 3 mm wider, a 1.86% difference in overall diameter.

With the speedometer calibrated for 315/70R17, an indicated 60 mph is actually 61.1 mph on 35x12.50R17, and revolutions per mile change from 587 to 576.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 315/70R17

Other comparisons with 35x12.50R17

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.