TireSizesFinder

37x12.50R18 vs 37x13.50R18

37x13.50R18 is 0.00 in (0.0 mm) taller than 37x12.50R18, a 0.00% diameter difference. With the speedometer set for 37x12.50R18, an indicated 60 mph is 60.0 mph on 37x13.50R18.

Is this a safe swap?

Diameter difference 0.00%: under 1%

By overall diameter alone, 37x13.50R18 is a near match for 37x12.50R18; 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: 37x12.50R18 (37.00 in) vs 37x13.50R18 (37.00 in)37x12.50R1837.00 in × 12.50 in37x13.50R1837.00 in × 13.50 in
Side profile and tread width, drawn to the same scale.
37x12.50R18 vs 37x13.50R18 differences
Measurement37x12.50R1837x13.50R18Difference% diff
Overall diameter37.00 in (939.8 mm)37.00 in (939.8 mm)0.00 in (0.0 mm)0.00%
Sidewall height9.50 in (241.3 mm)9.50 in (241.3 mm)0.00 in (0.0 mm)0.00%
Section width12.50 in (317.5 mm)13.50 in (342.9 mm)+1.00 in (+25.4 mm)+8.00%
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 37x12.50R18
IndicatedActual on 37x12.50R18Actual on 37x13.50R18Difference
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: 37x13.50R18 does not change the vehicle at the axle (half the 0.0 mm diameter difference).

37x13.50R18 is the same height as 37x12.50R18 and 25 mm wider, a 0.00% difference in overall diameter.

With the speedometer calibrated for 37x12.50R18, an indicated 60 mph is actually 60.0 mph on 37x13.50R18, and revolutions per mile change from 545 to 545.

Both sizes mount on 18-inch wheels.

Size pages

Other comparisons with 37x12.50R18

Other comparisons with 37x13.50R18

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