275/45R19 vs 245/65R17
245/65R17 has an overall diameter of 750.3 mm (29.54") compared with 730.1 mm (28.74") for 275/45R19, a difference of +20.2 mm (+2.77 %). The sidewall changes by +35.5 mm, section width by -30 mm and ride height by +10.1 mm. Using the ETRTO rolling circumference, 275/45R19 turns 449 times per kilometre and 245/65R17 turns 437 times. With 245/65R17 fitted to a car calibrated for 275/45R19, an indicated 100 km/h is a true 102.8 km/h, and the odometer records 97.3 km for every 100 km driven. This is close to the commonly quoted 3 % tolerance, so check clearance and local rules.
Full comparison
| Measurement | 275/45R19 | 245/65R17 | Difference |
|---|---|---|---|
| Section width | 275 mm | 245 mm | -30 mm |
| Sidewall height | 123.8 mm | 159.3 mm | +35.5 mm |
| Rim diameter | 19" | 17" | -2.0" |
| Overall diameter | 730.1 mm (28.74") | 750.3 mm (29.54") | +20.2 mm (+2.77 %) |
| Static circumference | 2294 mm | 2357 mm | +63 mm |
| Rolling circumference (ETRTO) | 2227 mm | 2288 mm | +62 mm |
| Revs per km | 449 | 437 | -12 |
| Ride height | +10.1 mm | ||
| Inch equivalent | 28.7×10.8R19 | 29.5×9.6R17 | |
| Approved rim widths (approx.) | 8.5″–10″ | 6.5″–8″ |
Speedometer error
| Speedo reads | 40 | 50 | 60 | 80 | 100 | 110 |
|---|---|---|---|---|---|---|
| Actual speed (km/h) | 41.1 | 51.4 | 61.7 | 82.2 | 102.8 | 113.0 |
| Error (km/h) | +1.1 | +1.4 | +1.7 | +2.2 | +2.8 | +3.0 |
Assumes the speedo was accurate on 275/45R19. Odometer records 97.3 km for every 100 km actually driven.
- The 245/65R17 is 20.2 mm (2.77 %) larger in diameter, so your speedo will read low and your odometer will under-record distance.
- Section width changes by -30 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.
Is 245/65R17 legal in Australia? Needs certification
| Overall diameter (VSB 14 LS 4.2.4) 245/65R17 is 20.2 mm larger than 275/45R19; 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 lower: at an indicated 100 km/h you would be doing 102.8 km/h. ADR 18 requires the speedo never to read below true speed, but factory speedos typically over-read by 2-6 %, so a 2.8 % increase is usually absorbed. Verify with a GPS speed app after fitting. | Verify |
| 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 245/65R17 instead of 275/45R19?
Overall diameter changes by +20.2 mm (+2.77 %). 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 245/65R17?
Your speedo will read low by about 2.77 %. At an indicated 100 km/h you would actually be travelling 102.8 km/h, and at 110 km/h about 113 km/h.
What is the rolling circumference of 245/65R17?
Static circumference is 2357 mm; the ETRTO rolling circumference under load is about 2288 mm, which is 437 revolutions per kilometre.
245/65R17 in inches
245/65R17 is approximately 29.5×9.6R17: 29.5" tall, 9.6" wide, on a 17" rim, with a 6.3" sidewall.
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