TireSizesFinder

35x12.50R15 vs 315/70R17

315/70R17 is 0.64 in (16.2 mm) shorter than 35x12.50R15, a −1.82% diameter difference. With the speedometer set for 35x12.50R15, an indicated 60 mph is 58.9 mph on 315/70R17.

Is this a safe swap?

Diameter difference −1.82%: within the ±3% guideline

By overall diameter alone, 315/70R17 falls inside the ±3% range commonly used as a guideline when replacing 35x12.50R15. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 35x12.50R15 (35.00 in) vs 315/70R17 (34.36 in)35x12.50R1535.00 in × 12.50 in315/70R1734.36 in × 12.40 in
Side profile and tread width, drawn to the same scale.
35x12.50R15 vs 315/70R17 differences
Measurement35x12.50R15315/70R17Difference% diff
Overall diameter35.00 in (889.0 mm)34.36 in (872.8 mm)−0.64 in (−16.2 mm)−1.82%
Sidewall height10.00 in (254.0 mm)8.68 in (220.5 mm)−1.32 in (−33.5 mm)−13.19%
Section width12.50 in (317.5 mm)12.40 in (315.0 mm)−0.10 in (−2.5 mm)−0.79%
Circumference109.96 in (2,792.9 mm)107.95 in (2,742.0 mm)−2.00 in (−50.9 mm)−1.82%
Revolutions per mile576587+11+1.86%
True speed with the speedometer calibrated for 35x12.50R15
IndicatedActual on 35x12.50R15Actual on 315/70R17Difference
30 mph30.0 mph29.5 mph−0.5 mph
60 mph60.0 mph58.9 mph−1.1 mph
75 mph75.0 mph73.6 mph−1.4 mph

Ride-height change: 315/70R17 lowers the vehicle by 0.32 in (8.1 mm) at the axle (half the −16.2 mm diameter difference).

315/70R17 is 0.64 in shorter than 35x12.50R15 and 3 mm narrower, a 1.82% difference in overall diameter.

With the speedometer calibrated for 35x12.50R15, an indicated 60 mph is actually 58.9 mph on 315/70R17, and revolutions per mile change from 576 to 587.

315/70R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 35x12.50R15.

Size pages

Other comparisons with 35x12.50R15

Other comparisons with 315/70R17

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.