235/60R16 vs 205/65R16
New overall diameter
26.49″
was 27.10″
True speed at an indicated 60
58.6 mph
your speedo reads high
Revolutions per mile
761
was 744, +17
| Measurement | 235/60R16 | 205/65R16 | Change |
|---|---|---|---|
| Overall diameter | 27.10″ | 26.49″ | −0.61″ (−2.3%) |
| Sidewall height | 5.55″ (141.0 mm) | 5.25″ (133.3 mm) | −7.8 mm |
| Tread width | 235 mm | 205 mm | −30 mm |
| Circumference | 85.14″ | 83.23″ | −1.92″ |
| Revs per mile | 744 | 761 | +17 |
| Speedometer error | baseline | −2.3% | reads high |
Diameter overlay
235/60R16 205/65R16
Speedometer check
With 205/65R16 fitted, when the speedometer shows the indicated speed, your actual speed is:
25 mph shown
24.4 mph actual
35 mph shown
34.2 mph actual
45 mph shown
44.0 mph actual
55 mph shown
53.8 mph actual
65 mph shown
63.5 mph actual
75 mph shown
73.3 mph actual
Common questions
- Will 205/65R16 fit instead of 235/60R16?
- Diameter moves 2.3%, comfortably inside the 3% rule. Your speedometer, ABS, traction control and gearing all stay in the range they were calibrated for. Your speedometer will read high, so you are going slower than it says. Overall diameter goes from 27.10″ to 26.49″, a change of −2.3%. The rule of thumb most shops use: under 3% is fine, 3 to 5% needs a clearance check, over 5% needs recalibration.
- How far off will my speedometer read on 205/65R16?
- At an indicated 60 mph you are really doing about 58.6 mph, a −2.3% error. The speedometer reads high, so you are going slower than it shows.
- What is the difference in revolutions per mile between 235/60R16 and 205/65R16?
- 235/60R16 turns about 744 times per mile and 205/65R16 turns about 761, a difference of +17. Your speedometer and odometer both count rotations, so this number is what throws them off.