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Tire Size Comparison

175/65R15 vs 205/55R16

Switching from 175/65R15 to 205/55R16 changes overall diameter by +3.85% (23.96 in → 24.88 in).

+3.85%Borderline — noticeable speedometer/odometer error

Speedometer error

With a speedometer calibrated to 175/65R15, fitting 205/55R16 makes it read as follows:

Speedo showsTrue speedSpeedo showsTrue speed
40 km/h41.5 km/h25 mph26 mph
60 km/h62.3 km/h37 mph39 mph
80 km/h83.1 km/h50 mph52 mph
100 km/h103.8 km/h62 mph65 mph
120 km/h124.6 km/h75 mph77 mph

Full comparison

175/65R15
Overall diameter608.5 mm · 23.96 in
Section width175 mm · 6.89 in
Sidewall height113.8 mm · 4.48 in
Circumference1911.7 mm · 75.3 in
Revolutions per mile842
Revolutions per km523
205/55R16
Overall diameter631.9 mm · 24.88 in
Section width205 mm · 8.07 in
Sidewall height112.8 mm · 4.44 in
Circumference1985.2 mm · 78.2 in
Revolutions per mile811
Revolutions per km504
Original tire
New tire
+3.85%Borderline — noticeable speedometer/odometer error
2424.9
Original
Overall diameter608.5 mm · 23.96 in
Sidewall height113.8 mm
Circumference1,911.7 mm
Revolutions / mile841.9
New
Overall diameter631.9 mm · 24.88 in
Sidewall height112.8 mm
Circumference1,985.2 mm
Revolutions / mile810.7
Speedometer & odometer error

The new tire changes overall diameter by +3.85%. With a speedometer calibrated to the original tire, that same percentage is how far the speedometer and odometer read off — a taller tire means your true speed is higher than indicated and the odometer under-counts distance.

Speedo showsTrue speedSpeedo showsTrue speed
40 km/h41.5 km/h25 mph26 mph
60 km/h62.3 km/h37 mph39 mph
80 km/h83.1 km/h50 mph52 mph
100 km/h103.8 km/h62 mph65 mph
120 km/h124.6 km/h75 mph77 mph

See individual specs: 175/65R15 · 205/55R16. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.