Question 1

Which tire is taller, 205/65 R15 or 205/50 R16?

Accepted Answer

205/65 R15 is taller by 36.1 mm (5.58%) compared with 205/50 R16.

Question 2

What is the diameter difference between 205/65 R15 and 205/50 R16?

Accepted Answer

205/65 R15 measures 648 mm overall diameter, 205/50 R16 measures 611 mm — a difference of 36.1 mm (5.58%).

Question 3

How much speedometer error does this change create?

Accepted Answer

Switching from 205/65 R15 to 205/50 R16 changes the speedometer reading by -5.58%. At an indicated 100 km/h, your true speed becomes about 94.4 km/h.

Question 4

Is 205/50 R16 a safe replacement for 205/65 R15?

Accepted Answer

Over 5% diameter difference. This is outside the common safe range and can affect speedometer accuracy, ABS calibration and gearing. Not recommended without professional review.

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	205/65 R15	205/50 R16	Difference
Overall diameter	647.5 mm	611.4 mm	-36.1 mm (-5.58%)
Sidewall height	133.3 mm	102.5 mm	-30.8 mm
Circumference	2.034 m	1.921 m	-113.4 mm
Revs / km	491.6	520.6	+29.0
Ground clearance	reference	-18.1 mm	-18.1 mm
Speedometer @ 100 km/h	100.0 km/h	94.4 km/h	-5.58 km/h

205/65 R15 vs 205/50 R16

Detailed comparison

Verdict: danger

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