245/70R16 vs 265/70R16
265/70R16 has an overall diameter of 777.4 mm (30.61") compared with 749.4 mm (29.50") for 245/70R16, a difference of +28.0 mm (+3.74 %). The sidewall changes by +14.0 mm, section width by +20 mm and ride height by +14.0 mm. Using the ETRTO rolling circumference, 245/70R16 turns 438 times per kilometre and 265/70R16 turns 422 times. With 265/70R16 fitted to a car calibrated for 245/70R16, an indicated 100 km/h is a true 103.7 km/h, and the odometer records 96.4 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 | 245/70R16 | 265/70R16 | Difference |
|---|---|---|---|
| Section width | 245 mm | 265 mm | +20 mm |
| Sidewall height | 171.5 mm | 185.5 mm | +14.0 mm |
| Rim diameter | 16" | 16" | 0.0" |
| Overall diameter | 749.4 mm (29.50") | 777.4 mm (30.61") | +28.0 mm (+3.74 %) |
| Static circumference | 2354 mm | 2442 mm | +88 mm |
| Rolling circumference (ETRTO) | 2286 mm | 2371 mm | +85 mm |
| Revs per km | 438 | 422 | -16 |
| Ride height | +14.0 mm | ||
| Inch equivalent | 29.5×9.6R16 | 30.6×10.4R16 | |
| Approved rim widths (approx.) | 6.5″–8″ | 7.5″–9″ |
Speedometer error
| Speedo reads | 40 | 50 | 60 | 80 | 100 | 110 |
|---|---|---|---|---|---|---|
| Actual speed (km/h) | 41.5 | 51.9 | 62.2 | 83.0 | 103.7 | 114.1 |
| Error (km/h) | +1.5 | +1.9 | +2.2 | +3.0 | +3.7 | +4.1 |
Assumes the speedo was accurate on 245/70R16. Odometer records 96.4 km for every 100 km actually driven.
- The 265/70R16 is 28 mm (3.74 %) 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.
- 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 265/70R16 legal in Australia? Needs certification
| Overall diameter (VSB 14 LS 4.2.4) 265/70R16 is 28.0 mm larger than 245/70R16; 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 103.7 km/h. ADR 18 requires the speedo never to read below true speed; a 3.7 % 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 265/70R16 instead of 245/70R16?
Overall diameter changes by +28.0 mm (+3.74 %). 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 265/70R16?
Your speedo will read low by about 3.74 %. At an indicated 100 km/h you would actually be travelling 103.7 km/h, and at 110 km/h about 114.1 km/h.
What is the rolling circumference of 265/70R16?
Static circumference is 2442 mm; the ETRTO rolling circumference under load is about 2371 mm, which is 422 revolutions per kilometre.
265/70R16 in inches
265/70R16 is approximately 30.6×10.4R16: 30.6" tall, 10.4" wide, on a 16" rim, with a 7.3" sidewall.
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