TireSizesFinder

27x8.50R14 vs 205/75R15

205/75R15 is 0.11 in (2.7 mm) taller than 27x8.50R14, a +0.39% diameter difference. With the speedometer set for 27x8.50R14, an indicated 60 mph is 60.2 mph on 205/75R15.

Is this a safe swap?

Diameter difference +0.39%: under 1%

By overall diameter alone, 205/75R15 is a near match for 27x8.50R14; 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: 27x8.50R14 (27.00 in) vs 205/75R15 (27.11 in)27x8.50R1427.00 in × 8.50 in205/75R1527.11 in × 8.07 in
Side profile and tread width, drawn to the same scale.
27x8.50R14 vs 205/75R15 differences
Measurement27x8.50R14205/75R15Difference% diff
Overall diameter27.00 in (685.8 mm)27.11 in (688.5 mm)+0.11 in (+2.7 mm)+0.39%
Sidewall height6.50 in (165.1 mm)6.05 in (153.8 mm)−0.45 in (−11.3 mm)−6.87%
Section width8.50 in (215.9 mm)8.07 in (205.0 mm)−0.43 in (−10.9 mm)−5.05%
Circumference84.82 in (2,154.5 mm)85.16 in (2,163.0 mm)+0.33 in (+8.5 mm)+0.39%
Revolutions per mile747744−3−0.39%
True speed with the speedometer calibrated for 27x8.50R14
IndicatedActual on 27x8.50R14Actual on 205/75R15Difference
30 mph30.0 mph30.1 mph+0.1 mph
60 mph60.0 mph60.2 mph+0.2 mph
75 mph75.0 mph75.3 mph+0.3 mph

Ride-height change: 205/75R15 raises the vehicle by 0.05 in (1.4 mm) at the axle (half the +2.7 mm diameter difference).

205/75R15 is 0.11 in taller than 27x8.50R14 and 11 mm narrower, a 0.39% difference in overall diameter.

With the speedometer calibrated for 27x8.50R14, an indicated 60 mph is actually 60.2 mph on 205/75R15, and revolutions per mile change from 747 to 744.

205/75R15 mounts on a 15-inch wheel, a plus-1 fitment from the 14-inch wheel of 27x8.50R14.

Size pages

Other comparisons with 27x8.50R14

Other comparisons with 205/75R15

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