265/70R16 vs 285/75R16
285/75R16 has an overall diameter of 833.9 mm (32.83") compared with 777.4 mm (30.61") for 265/70R16, a difference of +56.5 mm (+7.27 %). The sidewall changes by +28.3 mm, section width by +20 mm and ride height by +28.3 mm. Using the ETRTO rolling circumference, 265/70R16 turns 422 times per kilometre and 285/75R16 turns 393 times. With 285/75R16 fitted to a car calibrated for 265/70R16, an indicated 100 km/h is a true 107.3 km/h, and the odometer records 93.2 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 | 265/70R16 | 285/75R16 | Difference |
|---|---|---|---|
| Section width | 265 mm | 285 mm | +20 mm |
| Sidewall height | 185.5 mm | 213.8 mm | +28.3 mm |
| Rim diameter | 16" | 16" | 0.0" |
| Overall diameter | 777.4 mm (30.61") | 833.9 mm (32.83") | +56.5 mm (+7.27 %) |
| Static circumference | 2442 mm | 2620 mm | +177 mm |
| Rolling circumference (ETRTO) | 2371 mm | 2543 mm | +172 mm |
| Revs per km | 422 | 393 | -29 |
| Ride height | +28.3 mm | ||
| Inch equivalent | 30.6×10.4R16 | 32.8×11.2R16 | |
| Approved rim widths (approx.) | 7.5″–9″ | 7.5″–9″ |
Speedometer error
| Speedo reads | 40 | 50 | 60 | 80 | 100 | 110 |
|---|---|---|---|---|---|---|
| Actual speed (km/h) | 42.9 | 53.6 | 64.4 | 85.8 | 107.3 | 118.0 |
| Error (km/h) | +2.9 | +3.6 | +4.4 | +5.8 | +7.3 | +8.0 |
Assumes the speedo was accurate on 265/70R16. Odometer records 93.2 km for every 100 km actually driven.
- The 285/75R16 is 56.5 mm (7.27 %) 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 285/75R16 legal in Australia? Needs certification
| Overall diameter (VSB 14 LS 4.2.4) 285/75R16 is 56.5 mm larger than 265/70R16; 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 107.3 km/h. ADR 18 requires the speedo never to read below true speed; a 7.3 % 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 285/75R16 instead of 265/70R16?
Overall diameter changes by +56.5 mm (+7.27 %). 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 285/75R16?
Your speedo will read low by about 7.27 %. At an indicated 100 km/h you would actually be travelling 107.3 km/h, and at 110 km/h about 118 km/h.
What is the rolling circumference of 285/75R16?
Static circumference is 2620 mm; the ETRTO rolling circumference under load is about 2543 mm, which is 393 revolutions per kilometre.
285/75R16 in inches
285/75R16 is approximately 32.8×11.2R16: 32.8" tall, 11.2" wide, on a 16" rim, with a 8.4" sidewall.
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