What changes between these markings
At a fixed 70-percent aspect ratio, 20 mm more nominal width adds 14 mm to each sidewall. The diameter therefore grows by 28 mm even though both markings use a 17-inch rim. A 14 mm radius change is geometric; it is not a measured lift or a clearance guarantee.
With 265/70R17 as original and 285/70R17 as new, nominal diameter changes from 802.8 to 830.8 mm: +28 mm (+3.49%). Nominal section width changes by +20 mm and sidewall height by +14 mm per side.
Circumference and theoretical speed
Calculated circumference changes from 2522.07 to 2610.04 mm. Revolutions per kilometer change from 396.5 to 383.14, a −3.37% change. Circumference follows diameter in this circular model; revolution counts move in the opposite direction.
At an indicated 100 km/h, the size-ratio calculation gives 103.49 km/h for the new size. At an indicated 60 mph it gives 62.09 mph. Both examples assume calibration corresponds to the original nominal circumference and ignore existing instrument bias and real rolling deformation.
Keep the comparison direction explicit
The published URL keeps one stable order for this pair. Here 265/70R17 is the original denominator. Reversing the inputs gives a −3.37% diameter change and 96.63 km/h at an indicated 100 km/h. Use Swap in the editable tool to inspect that direction; changing only the sign would be inaccurate.
Half of the diameter difference is +14 mm of nominal radius change. It is not a measured ride-height change, and the width difference does not locate the installed sidewall without wheel and product information.
Why this pair has a reference page
A Ranger5G author asks whether to change an order from 265/70R17 to 285/70R17 after selecting suspension modifications. The exact pair supplies editorial context. Those modifications and the replies do not establish general clearance or fitment, and the 285/70R17 manufacturer evidence retains its LT prefix.
The linked manufacturer entries establish the individual size markings. The public discussion establishes an editorial reason to compare them. Neither source role supplies a fitment approval, search-volume estimate, purchase recommendation or universal acceptable percentage. Check complete vehicle and product requirements separately.
Sources and further reading
- Grabber APT — Specifications — General Tire
- Grabber A/TX — Specifications — General Tire
- 265/70r17 or 285/70r17? — Ranger5G
- Tire glossary — Michelin