225/65R17 vs 245/45R19
245/45R19 has an overall diameter of 703.1 mm (27.68") compared with 724.3 mm (28.52") for 225/65R17, a difference of -21.2 mm (-2.93 %). The sidewall changes by -36.0 mm, section width by +20 mm and ride height by -10.6 mm. Using the ETRTO rolling circumference, 225/65R17 turns 453 times per kilometre and 245/45R19 turns 466 times. With 245/45R19 fitted to a car calibrated for 225/65R17, an indicated 100 km/h is a true 97.1 km/h, and the odometer records 103 km for every 100 km driven. This is close to the commonly quoted 3 % tolerance, so check clearance and local rules.
Full comparison
| Measurement | 225/65R17 | 245/45R19 | Difference |
|---|---|---|---|
| Section width | 225 mm | 245 mm | +20 mm |
| Sidewall height | 146.3 mm | 110.3 mm | -36.0 mm |
| Rim diameter | 17" | 19" | +2.0" |
| Overall diameter | 724.3 mm (28.52") | 703.1 mm (27.68") | -21.2 mm (-2.93 %) |
| Static circumference | 2275 mm | 2209 mm | -67 mm |
| Rolling circumference (ETRTO) | 2209 mm | 2144 mm | -65 mm |
| Revs per km | 453 | 466 | +14 |
| Ride height | -10.6 mm | ||
| Inch equivalent | 28.5×8.9R17 | 27.7×9.6R19 | |
| Approved rim widths (approx.) | 6″–7.5″ | 7.5″–9″ |
Speedometer error
| Speedo reads | 40 | 50 | 60 | 80 | 100 | 110 |
|---|---|---|---|---|---|---|
| Actual speed (km/h) | 38.8 | 48.5 | 58.2 | 77.7 | 97.1 | 106.8 |
| Error (km/h) | -1.2 | -1.5 | -1.8 | -2.3 | -2.9 | -3.2 |
Assumes the speedo was accurate on 225/65R17. Odometer records 103.0 km for every 100 km actually driven.
- The 245/45R19 is 21.2 mm (2.93 %) smaller in diameter, so your speedo will read high and your odometer will over-record distance.
- Section width changes by +20 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 19", so new wheels are required.
Is 245/45R19 legal in Australia? More info needed
| Overall diameter (VSB 14 LS 4.2.4) Diameter change of -21.2 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 97.1 km/h (over-read 2.9 km/h; ADR 18 allows up to 13.7 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 245/45R19 instead of 225/65R17?
Overall diameter changes by -21.2 mm (-2.93 %). 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 245/45R19?
Your speedo will read high by about 2.93 %. At an indicated 100 km/h you would actually be travelling 97.1 km/h, and at 110 km/h about 106.8 km/h.
What is the rolling circumference of 245/45R19?
Static circumference is 2209 mm; the ETRTO rolling circumference under load is about 2144 mm, which is 466 revolutions per kilometre.
245/45R19 in inches
245/45R19 is approximately 27.7×9.6R19: 27.7" tall, 9.6" wide, on a 19" rim, with a 4.3" sidewall.
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