Question 1

Which tire is taller, 265/60 R18 or 305/40 R22?

Accepted Answer

305/40 R22 is taller by 27.6 mm (3.56%) compared with 265/60 R18.

Question 2

What is the diameter difference between 265/60 R18 and 305/40 R22?

Accepted Answer

265/60 R18 measures 775 mm overall diameter, 305/40 R22 measures 803 mm — a difference of 27.6 mm (3.56%).

Question 3

How much speedometer error does this change create?

Accepted Answer

Switching from 265/60 R18 to 305/40 R22 changes the speedometer reading by +3.56%. At an indicated 100 km/h, your true speed becomes about 103.6 km/h.

Question 4

Is 305/40 R22 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	305/40 R22	Difference
Overall diameter	775.2 mm	802.8 mm	+27.6 mm (+3.56%)
Sidewall height	159.0 mm	122.0 mm	-37.0 mm
Circumference	2.435 m	2.522 m	+86.7 mm
Revs / km	410.6	396.5	-14.1
Ground clearance	reference	+13.8 mm	+13.8 mm
Speedometer @ 100 km/h	100.0 km/h	103.6 km/h	+3.56 km/h

265/60 R18 vs 305/40 R22

Detailed comparison

Verdict: warning

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