What is the diameter difference between 265/70R17 and 265/65R17?

265/70R17 has an overall diameter of 31.61 inches (803 mm). 265/65R17 is 30.56 inches (776 mm). That's a 1.04 inch (27 mm) difference — 265/65R17 is shorter.

Will 265/65R17 cause speedometer error on a car fitted with 265/70R17?

Swapping 265/70R17 for 265/65R17 produces a speedometer error of about 3.3%. Your speedometer will read higher than your actual speed — a 60 mph indicated reading is really 58 mph. Anything under 3% is usually acceptable without recalibration.

How many revolutions per mile does each size do?

265/70R17 turns 638 revs per mile. 265/65R17 turns 660 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.

What's the sidewall height difference?

265/70R17 has a sidewall of 186 mm (7.3 in). 265/65R17 sidewall is 172 mm (6.78 in). Lower-profile sidewalls give sharper steering response but less bump compliance.

Is 265/65R17 a safe plus-size upgrade from 265/70R17?

A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.3%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.

Tire size comparison

265/70R17 vs 265/65R17

Overall diameter, sidewall, revs per mile, and speedometer error — 265/70R17 is the taller tire, with a 3.3% speedo delta when swapping.

265/70R17

31.61in

803 mm overall diameter

265/65R17

30.56in

776 mm overall diameter

Diameter Δ

1.04 in

Speedo error

3.3%

265/70R17 revs/mi

638

265/65R17 revs/mi

660

Outside the typical ±3% safe plus-size band — you may want speedometer recalibration, and this change can affect ABS or traction control behaviour.

Full spec

Side by side

Metric	265/70R17	265/65R17
Section width	265 mm	265 mm
Aspect ratio	70	65
Wheel diameter	17″	17″
Sidewall height	186 mm	172 mm
Overall diameter	31.61 in (803 mm)	30.56 in (776 mm)
Circumference	99.29 in	96.02 in
Revolutions / mile	638	660

Other comparisons for these sizes

265/70R16 vs 265/65R17 265/70R17 vs 275/65R18

FAQ

Frequently asked

What is the diameter difference between 265/70R17 and 265/65R17?: 265/70R17 has an overall diameter of 31.61 inches (803 mm). 265/65R17 is 30.56 inches (776 mm). That's a 1.04 inch (27 mm) difference — 265/65R17 is shorter.
Will 265/65R17 cause speedometer error on a car fitted with 265/70R17?: Swapping 265/70R17 for 265/65R17 produces a speedometer error of about 3.3%. Your speedometer will read higher than your actual speed — a 60 mph indicated reading is really 58 mph. Anything under 3% is usually acceptable without recalibration.
How many revolutions per mile does each size do?: 265/70R17 turns 638 revs per mile. 265/65R17 turns 660 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.
What's the sidewall height difference?: 265/70R17 has a sidewall of 186 mm (7.3 in). 265/65R17 sidewall is 172 mm (6.78 in). Lower-profile sidewalls give sharper steering response but less bump compliance.
Is 265/65R17 a safe plus-size upgrade from 265/70R17?: A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.3%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.