16-inch rim · tyre size comparison

205/55 R16 vs 225/50 R16

225/50 R16 and 205/55 R16 are effectively the same height: 225/50 R16 is 0.5 mm shorter in overall diameter, a -0.08% difference. That is well inside the ±3% limit commonly used to screen a tire size change; it is a nominal calculation, not a fitment approval.

Diameter difference
-0.5 mm
-0.02 in · -0.08%
Indicated 70 mph
69.9 mph
Actual speed on 225/50 R16, if the speedometer was accurate on 205/55 R16.
Sidewall height
-0.25 mm
112.75 mm to 112.5 mm.
Compare in the calculator205/55 R16 size guide225/50 R16 size guideSpeedometerWhat changes

Dimensions side by side

205/55 R16 and 225/50 R16 dimensions
Measurement205/55 R16225/50 R16Difference
Overall diameter631.9 mm24.88 in631.4 mm24.86 in-0.5 mm (-0.08%)-0.02 in
Section width205 mm8.07 in225 mm8.86 in+20 mm+0.79 in
Sidewall height112.75 mm4.44 in112.5 mm4.43 in-0.25 mm-0.01 in
Circumference1,985.17 mm78.16 in1,983.6 mm78.09 in-1.57 mm-0.06 in
Rim diameter406.4 mm16 in406.4 mm16 in0 mm0 in
Revolutions per mile810.68811.32+0.64
Revolutions per km503.73504.13+0.4
205/55 R16225/50 R16
Nominal diameters at the same scale. The inner circle is the rim.

Calculated from the nominal size codes, without load or tread wear. Real tyres vary by model, rim width and pressure, so the exact tyre's published dimensions take priority.

Speedometer with 225/50 R16

If the speedometer was accurate on 205/55 R16, fitting 225/50 R16 means the car is travelling 0.08% slower than it shows, and the odometer over-records distance by about the same amount.

Indicated speed versus calculated road speed on 225/50 R16
Speedometer showsActual on 225/50 R16Difference
30 mph29.98 mph-0.02 mph
50 mph49.96 mph-0.04 mph
60 mph59.95 mph-0.05 mph
70 mph69.94 mph-0.06 mph
50 km/h49.96 km/h-0.04 km/h
100 km/h99.92 km/h-0.08 km/h

UN ECE Regulation 39, used in the UK and EU, does not allow a speedometer to show less than the true speed, so many read slightly high from the factory. A shorter tyre adds to it. Calibration varies by car; these figures are the tyre-size effect only.

What changes from 205/55 R16 to 225/50 R16

  • Wheels

    Both fit 16-inch wheels. Our rim-width starting estimate is 6 to 7 inches for 205/55 R16 and 6.5 to 7.5 inches for 225/50 R16, so a 6.5 to 7-inch wheel sits in both ranges. The exact tyre's approved rim range takes priority.

  • Sidewall and ride comfort

    Sidewall height differs by only 0.25 mm (112.75 vs 112.5 mm), so ride comfort and steering feel will depend more on the tyre model and pressures than on the size.

  • Contact width

    225/50 R16 is 20 mm wider in nominal section width (9.8%). A wider tyre usually puts a wider, shorter contact patch on the road, which can help dry grip, but it may follow ruts more, clear standing water less readily and add some rolling resistance.

  • Wheel well clearance

    Ride height is effectively unchanged. On the same wheel width and offset, each sidewall moves about 10 mm further out towards the arch lip and further in towards the suspension. Check clearance at full steering lock and full suspension compression, especially on a lowered car.

  • Gearing

    Effective gearing changes by +0.08%, too little to notice from the driver's seat.

  • ABS, stability control and AWD

    These systems compare wheel speeds. Fit the same size on both ends of an axle, and follow the car maker's rolling-circumference limits, which can be much tighter than 3%.

General tendencies from the nominal numbers, not a test of any tyre. Load index, speed rating, tyre construction and the car's approved sizes matter more than these rules of thumb.

Cars in our guides using these sizes

Factory trims and popular community setups from our fitment guides. A popular setup is not a factory approval; each guide explains its trims, axles and clearance limits.

More comparisons

Questions

Can I use 225/50 R16 instead of 205/55 R16?

Both fit 16-inch wheels. The diameter difference is -0.08%, well inside the ±3% screening limit. That does not approve fitment: check the car maker's approved sizes, load index, speed rating, rim width and clearance first.

How much bigger is 225/50 R16 than 205/55 R16?

Overall diameter is 0.5 mm (0.02 in) smaller: 631.4 vs 631.9 mm. Section width is 20 mm wider, and the sidewall is 0.25 mm shorter. These are nominal figures; real tyres vary by model and rim width.

Will 225/50 R16 change my speedometer reading?

Yes, by 0.08%. If the speedometer was accurate on 205/55 R16, an indicated 60 mph would be about 60 mph on 225/50 R16, and an indicated 100 km/h about 99.9 km/h. You would be going slower than the speedometer shows.

Which is better, 205/55 R16 or 225/50 R16?

Neither in general. 225/50 R16 is wider, which can help dry grip; the narrower size is usually better in standing water and snow. The size listed for your car's trim, on its placard or in the handbook, is the safe default.

Check the exact tyre

Size codes give nominal dimensions. Before buying, confirm the size is approved for your car and check the exact tyre's load and speed ratings and published dimensions.