215/50R17 vs 205/55R16
205/55R16 has an overall diameter of 631.9 mm (24.88") compared with 646.8 mm (25.46") for 215/50R17, a difference of -14.9 mm (-2.30 %). The sidewall changes by +5.3 mm, section width by -10 mm and ride height by -7.4 mm. Using the ETRTO rolling circumference, 215/50R17 turns 507 times per kilometre and 205/55R16 turns 519 times. With 205/55R16 fitted to a car calibrated for 215/50R17, an indicated 100 km/h is a true 97.7 km/h, and the odometer records 102.4 km for every 100 km driven. This is close to the commonly quoted 3 % tolerance, so check clearance and local rules.
Full comparison
| Measurement | 215/50R17 | 205/55R16 | Difference |
|---|---|---|---|
| Section width | 215 mm | 205 mm | -10 mm |
| Sidewall height | 107.5 mm | 112.8 mm | +5.3 mm |
| Rim diameter | 17" | 16" | -1.0" |
| Overall diameter | 646.8 mm (25.46") | 631.9 mm (24.88") | -14.9 mm (-2.30 %) |
| Static circumference | 2032 mm | 1985 mm | -47 mm |
| Rolling circumference (ETRTO) | 1973 mm | 1927 mm | -45 mm |
| Revs per km | 507 | 519 | +12 |
| Ride height | -7.4 mm | ||
| Inch equivalent | 25.5×8.5R17 | 24.9×8.1R16 | |
| Approved rim widths (approx.) | 6″–8″ | 5.5″–7.5″ |
Speedometer error
| Speedo reads | 40 | 50 | 60 | 80 | 100 | 110 |
|---|---|---|---|---|---|---|
| Actual speed (km/h) | 39.1 | 48.8 | 58.6 | 78.2 | 97.7 | 107.5 |
| Error (km/h) | -0.9 | -1.2 | -1.4 | -1.8 | -2.3 | -2.5 |
Assumes the speedo was accurate on 215/50R17. Odometer records 102.4 km for every 100 km actually driven.
- The 205/55R16 is 14.9 mm (2.3 %) smaller in diameter, so your speedo will read high and your odometer will over-record distance.
- Section width changes by -10 mm. Check guard, strut and inner-arch clearance and that the rim width is within the approved range for the new tyre.
- Rim diameter changes from 17" to 16", so new wheels are required.
Is 205/55R16 legal in Australia? More info needed
| Overall diameter (VSB 14 LS 4.2.4) Diameter change of -14.9 mm is within the +15 mm / -26 mm allowance for a passenger car (MA/MB) (measured against the largest size the manufacturer designates for the model). | OK |
| Speedometer (ADR 18/03) A smaller tyre makes the speedo read high: at an indicated 100 km/h you would be doing 97.7 km/h (over-read 2.3 km/h; ADR 18 allows up to 13.8 km/h at that speed). | OK |
| Load index (tyre placard / ADR 42) Enter the placard load index and the replacement tyre load index to check. | ? |
| Speed rating (tyre placard / ADR 42) Enter the placard speed rating and the replacement tyre speed rating to check. | ? |
Frequently asked
Can I fit 205/55R16 instead of 215/50R17?
Overall diameter changes by -14.9 mm (-2.30 %). That is close to the 3 % rule of thumb; it may fit, but check guard, strut and brake clearance and your local rules. In Australia VSB 14 allows up to +15 mm for passenger cars and +50 mm for 4WDs/goods vehicles without certification.
How much will my speedo be out with 205/55R16?
Your speedo will read high by about 2.30 %. At an indicated 100 km/h you would actually be travelling 97.7 km/h, and at 110 km/h about 107.5 km/h.
What is the rolling circumference of 205/55R16?
Static circumference is 1985 mm; the ETRTO rolling circumference under load is about 1927 mm, which is 519 revolutions per kilometre.
205/55R16 in inches
205/55R16 is approximately 24.9×8.1R16: 24.9" tall, 8.1" wide, on a 16" rim, with a 4.4" sidewall.
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