Question 1

Which tire is taller, 265/60 R18 or 295/40 R20?

Accepted Answer

265/60 R18 is taller by 31.2 mm (4.02%) compared with 295/40 R20.

Question 2

What is the diameter difference between 265/60 R18 and 295/40 R20?

Accepted Answer

265/60 R18 measures 775 mm overall diameter, 295/40 R20 measures 744 mm — a difference of 31.2 mm (4.02%).

Question 3

How much speedometer error does this change create?

Accepted Answer

Switching from 265/60 R18 to 295/40 R20 changes the speedometer reading by -4.02%. At an indicated 100 km/h, your true speed becomes about 96.0 km/h.

Question 4

Is 295/40 R20 a safe replacement for 265/60 R18?

Accepted Answer

Between 3% and 5% diameter difference — speedometer drift is noticeable. Consider recalibration and confirm clearance with your vehicle's manufacturer specification.

Question 5

What else should I check before changing tire size?

Accepted Answer

Beyond diameter and speedometer error, verify wheel offset (ET), rim width, hub bore, load index, brake and suspension clearance, and your vehicle's manufacturer specification. Local regulations may also limit how far you can deviate from OEM.

Metric	265/60 R18	295/40 R20	Difference
Overall diameter	775.2 mm	744.0 mm	-31.2 mm (-4.02%)
Sidewall height	159.0 mm	118.0 mm	-41.0 mm
Circumference	2.435 m	2.337 m	-98.0 mm
Revs / km	410.6	427.8	+17.2
Ground clearance	reference	-15.6 mm	-15.6 mm
Speedometer @ 100 km/h	100.0 km/h	96.0 km/h	-4.02 km/h

265/60 R18 vs 295/40 R20

Detailed comparison

Verdict: warning

Related comparisons

Frequently asked questions