35x12.50R17 vs 295/70R18

295/70R18 is 0.74 in (18.8 mm) shorter than 35x12.50R17, a −2.11% diameter difference. With the speedometer set for 35x12.50R17, an indicated 60 mph is 58.7 mph on 295/70R18.

Is this a safe swap?

Diameter difference −2.11%: within the ±3% guideline

By overall diameter alone, 295/70R18 falls inside the ±3% range commonly used as a guideline when replacing 35x12.50R17. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 35x12.50R17 (35.00 in) vs 295/70R18 (34.26 in)35x12.50R1735.00 in × 12.50 in295/70R1834.26 in × 11.61 in
Side profile and tread width, drawn to the same scale.
35x12.50R17 vs 295/70R18 differences
Measurement35x12.50R17295/70R18Difference% diff
Overall diameter35.00 in (889.0 mm)34.26 in (870.2 mm)−0.74 in (−18.8 mm)−2.11%
Sidewall height9.00 in (228.6 mm)8.13 in (206.5 mm)−0.87 in (−22.1 mm)−9.67%
Section width12.50 in (317.5 mm)11.61 in (295.0 mm)−0.89 in (−22.5 mm)−7.09%
Circumference109.96 in (2,792.9 mm)107.63 in (2,733.8 mm)−2.33 in (−59.1 mm)−2.11%
Revolutions per mile576589+12+2.16%
True speed with the speedometer calibrated for 35x12.50R17
IndicatedActual on 35x12.50R17Actual on 295/70R18Difference
30 mph30.0 mph29.4 mph−0.6 mph
60 mph60.0 mph58.7 mph−1.3 mph
75 mph75.0 mph73.4 mph−1.6 mph

Ride-height change: 295/70R18 lowers the vehicle by 0.37 in (9.4 mm) at the axle (half the −18.8 mm diameter difference).

295/70R18 is 0.74 in shorter than 35x12.50R17 and 23 mm narrower, a 2.11% difference in overall diameter.

With the speedometer calibrated for 35x12.50R17, an indicated 60 mph is actually 58.7 mph on 295/70R18, and revolutions per mile change from 576 to 589.

295/70R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 35x12.50R17.

Size pages

Other comparisons with 35x12.50R17

Other comparisons with 295/70R18

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