265/65R17 vs 265/70R17

What changes between these markings

A five-point aspect-ratio step at 265 mm width adds 13.25 mm per sidewall. That is a 26.5 mm increase in full diameter on an unchanged 17-inch rim. The calculation is independent of the specific brands in the discussion.

With 265/65R17 as original and 265/70R17 as new, nominal diameter changes from 776.3 to 802.8 mm: +26.5 mm (+3.41%). Nominal section width changes by 0 mm and sidewall height by +13.25 mm per side.

Circumference and theoretical speed

Calculated circumference changes from 2438.82 to 2522.07 mm. Revolutions per kilometer change from 410.03 to 396.5, a −3.3% 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 103.41 km/h for the new size. At an indicated 60 mph it gives 62.05 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 265/65R17 is the original denominator. Reversing the inputs gives a −3.3% diameter change and 96.7 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 +13.25 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 contributor posts a side-by-side comparison explicitly labeled 265/65R17 and 265/70R17. The two photographed products differ, so the photographs are editorial evidence for the pair, not measurements used by this model.

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.

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