Question 1

Which tire is taller, 185/55 R15 or 205/50 R16?

Accepted Answer

205/50 R16 is taller by 26.9 mm (4.60%) compared with 185/55 R15.

Question 2

What is the diameter difference between 185/55 R15 and 205/50 R16?

Accepted Answer

185/55 R15 measures 585 mm overall diameter, 205/50 R16 measures 611 mm — a difference of 26.9 mm (4.60%).

Question 3

How much speedometer error does this change create?

Accepted Answer

Switching from 185/55 R15 to 205/50 R16 changes the speedometer reading by +4.60%. At an indicated 100 km/h, your true speed becomes about 104.6 km/h.

Question 4

Is 205/50 R16 a safe replacement for 185/55 R15?

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	185/55 R15	205/50 R16	Difference
Overall diameter	584.5 mm	611.4 mm	+26.9 mm (+4.60%)
Sidewall height	101.8 mm	102.5 mm	+0.8 mm
Circumference	1.836 m	1.921 m	+84.5 mm
Revs / km	544.6	520.6	-24.0
Ground clearance	reference	+13.4 mm	+13.4 mm
Speedometer @ 100 km/h	100.0 km/h	104.6 km/h	+4.60 km/h

185/55 R15 vs 205/50 R16

Detailed comparison

Verdict: warning

Related comparisons

Frequently asked questions