245/45R19 vs 225/65R17
225/65R17 has an overall diameter of 724.3 mm (28.52") compared with 703.1 mm (27.68") for 245/45R19, a difference of +21.2 mm (+3.02 %). The sidewall changes by +36.0 mm, section width by -20 mm and ride height by +10.6 mm. Using the ETRTO rolling circumference, 245/45R19 turns 466 times per kilometre and 225/65R17 turns 453 times. With 225/65R17 fitted to a car calibrated for 245/45R19, an indicated 100 km/h is a true 103 km/h, and the odometer records 97.1 km for every 100 km driven. This exceeds the commonly quoted 3 % tolerance; check clearances, ABS/ESC calibration and local roadworthy rules (VSB 14 in Australia).
Full comparison
| Measurement | 245/45R19 | 225/65R17 | Difference |
|---|---|---|---|
| Section width | 245 mm | 225 mm | -20 mm |
| Sidewall height | 110.3 mm | 146.3 mm | +36.0 mm |
| Rim diameter | 19" | 17" | -2.0" |
| Overall diameter | 703.1 mm (27.68") | 724.3 mm (28.52") | +21.2 mm (+3.02 %) |
| Static circumference | 2209 mm | 2275 mm | +67 mm |
| Rolling circumference (ETRTO) | 2144 mm | 2209 mm | +65 mm |
| Revs per km | 466 | 453 | -14 |
| Ride height | +10.6 mm | ||
| Inch equivalent | 27.7×9.6R19 | 28.5×8.9R17 | |
| Approved rim widths (approx.) | 7.5″–9″ | 6″–7.5″ |
Speedometer error
| Speedo reads | 40 | 50 | 60 | 80 | 100 | 110 |
|---|---|---|---|---|---|---|
| Actual speed (km/h) | 41.2 | 51.5 | 61.8 | 82.4 | 103.0 | 113.3 |
| Error (km/h) | +1.2 | +1.5 | +1.8 | +2.4 | +3.0 | +3.3 |
Assumes the speedo was accurate on 245/45R19. Odometer records 97.1 km for every 100 km actually driven.
- The 225/65R17 is 21.2 mm (3.02 %) larger in diameter, so your speedo will read low and your odometer will under-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 19" to 17", so new wheels are required.
- A diameter change over 3 % is outside the usual rule of thumb; check local roadworthy rules (in Australia see VSB 14 / NCOP Section LS) and ABS/ESC calibration.
Is 225/65R17 legal in Australia? Needs certification
| Overall diameter (VSB 14 LS 4.2.4) 225/65R17 is 21.2 mm larger than 245/45R19; the limit without certification for a passenger car (MA/MB) is +15 mm. Larger increases need an approved signatory / engineering certificate (modification code LS or state equivalent) and may not be permitted at all. | Cert. |
| Speedometer (ADR 18/03) A larger tyre makes the speedo read low: at an indicated 100 km/h you would be doing 103.0 km/h. ADR 18 requires the speedo never to read below true speed; a 3.0 % increase is unlikely to be absorbed by the factory over-read, so the speedo will need recalibration (correction module) and certification. | Cert. |
| 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 225/65R17 instead of 245/45R19?
Overall diameter changes by +21.2 mm (+3.02 %). That is outside the 3 % rule of thumb, so it may rub, upset ABS/ESC calibration and may not be legal without certification. 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 225/65R17?
Your speedo will read low by about 3.02 %. At an indicated 100 km/h you would actually be travelling 103 km/h, and at 110 km/h about 113.3 km/h.
What is the rolling circumference of 225/65R17?
Static circumference is 2275 mm; the ETRTO rolling circumference under load is about 2209 mm, which is 453 revolutions per kilometre.
225/65R17 in inches
225/65R17 is approximately 28.5×8.9R17: 28.5" tall, 8.9" wide, on a 17" rim, with a 5.8" sidewall.
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