TireSizesFinder

37x12.50R17 vs 37x12.50R18

37x12.50R18 is 0.00 in (0.0 mm) taller than 37x12.50R17, a 0.00% diameter difference. With the speedometer set for 37x12.50R17, an indicated 60 mph is 60.0 mph on 37x12.50R18.

Is this a safe swap?

Diameter difference 0.00%: under 1%

By overall diameter alone, 37x12.50R18 is a near match for 37x12.50R17; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 37x12.50R17 (37.00 in) vs 37x12.50R18 (37.00 in)37x12.50R1737.00 in × 12.50 in37x12.50R1837.00 in × 12.50 in
Side profile and tread width, drawn to the same scale.
37x12.50R17 vs 37x12.50R18 differences
Measurement37x12.50R1737x12.50R18Difference% diff
Overall diameter37.00 in (939.8 mm)37.00 in (939.8 mm)0.00 in (0.0 mm)0.00%
Sidewall height10.00 in (254.0 mm)9.50 in (241.3 mm)−0.50 in (−12.7 mm)−5.00%
Section width12.50 in (317.5 mm)12.50 in (317.5 mm)0.00 in (0.0 mm)0.00%
Circumference116.24 in (2,952.5 mm)116.24 in (2,952.5 mm)0.00 in (0.0 mm)0.00%
Revolutions per mile54554500.00%
True speed with the speedometer calibrated for 37x12.50R17
IndicatedActual on 37x12.50R17Actual on 37x12.50R18Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph60.0 mph0.0 mph
75 mph75.0 mph75.0 mph0.0 mph

Ride-height change: 37x12.50R18 does not change the vehicle at the axle (half the 0.0 mm diameter difference).

37x12.50R18 is the same height as 37x12.50R17 and the same width, a 0.00% difference in overall diameter.

With the speedometer calibrated for 37x12.50R17, an indicated 60 mph is actually 60.0 mph on 37x12.50R18, and revolutions per mile change from 545 to 545.

37x12.50R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 37x12.50R17.

Size pages

Other comparisons with 37x12.50R17

Other comparisons with 37x12.50R18

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