TireSizesFinder

38x15.50R20 vs 37x13.50R22

37x13.50R22 is 1.00 in (25.4 mm) shorter than 38x15.50R20, a −2.63% diameter difference. With the speedometer set for 38x15.50R20, an indicated 60 mph is 58.4 mph on 37x13.50R22.

Is this a safe swap?

Diameter difference −2.63%: within the ±3% guideline

By overall diameter alone, 37x13.50R22 falls inside the ±3% range commonly used as a guideline when replacing 38x15.50R20. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 38x15.50R20 (38.00 in) vs 37x13.50R22 (37.00 in)38x15.50R2038.00 in × 15.50 in37x13.50R2237.00 in × 13.50 in
Side profile and tread width, drawn to the same scale.
38x15.50R20 vs 37x13.50R22 differences
Measurement38x15.50R2037x13.50R22Difference% diff
Overall diameter38.00 in (965.2 mm)37.00 in (939.8 mm)−1.00 in (−25.4 mm)−2.63%
Sidewall height9.00 in (228.6 mm)7.50 in (190.5 mm)−1.50 in (−38.1 mm)−16.67%
Section width15.50 in (393.7 mm)13.50 in (342.9 mm)−2.00 in (−50.8 mm)−12.90%
Circumference119.38 in (3,032.3 mm)116.24 in (2,952.5 mm)−3.14 in (−79.8 mm)−2.63%
Revolutions per mile531545+14+2.70%
True speed with the speedometer calibrated for 38x15.50R20
IndicatedActual on 38x15.50R20Actual on 37x13.50R22Difference
30 mph30.0 mph29.2 mph−0.8 mph
60 mph60.0 mph58.4 mph−1.6 mph
75 mph75.0 mph73.0 mph−2.0 mph

Ride-height change: 37x13.50R22 lowers the vehicle by 0.50 in (12.7 mm) at the axle (half the −25.4 mm diameter difference).

37x13.50R22 is 1.00 in shorter than 38x15.50R20 and 51 mm narrower, a 2.63% difference in overall diameter.

With the speedometer calibrated for 38x15.50R20, an indicated 60 mph is actually 58.4 mph on 37x13.50R22, and revolutions per mile change from 531 to 545.

37x13.50R22 mounts on a 22-inch wheel, a plus-2 fitment from the 20-inch wheel of 38x15.50R20.

Size pages

Other comparisons with 38x15.50R20

Other comparisons with 37x13.50R22

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