195/55R16 vs 195/65R15
New overall diameter
24.98″
was 24.44″
True speed at an indicated 60
61.3 mph
your speedo reads low
Revolutions per mile
807
was 825, −18
| Measurement | 195/55R16 | 195/65R15 | Change |
|---|---|---|---|
| Overall diameter | 24.44″ | 24.98″ | +0.54″ (+2.2%) |
| Sidewall height | 4.22″ (107.3 mm) | 4.99″ (126.8 mm) | +19.5 mm |
| Tread width | 195 mm | 195 mm | +0 mm |
| Circumference | 76.80″ | 78.48″ | +1.68″ |
| Revs per mile | 825 | 807 | −18 |
| Speedometer error | baseline | +2.2% | reads low |
Diameter overlay
195/55R16 195/65R15
Speedometer check
With 195/65R15 fitted, when the speedometer shows the indicated speed, your actual speed is:
25 mph shown
25.5 mph actual
35 mph shown
35.8 mph actual
45 mph shown
46.0 mph actual
55 mph shown
56.2 mph actual
65 mph shown
66.4 mph actual
75 mph shown
76.6 mph actual
Common questions
- Will 195/65R15 fit instead of 195/55R16?
- Diameter moves 2.2%, 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 low, so you are going faster than it says. Overall diameter goes from 24.44″ to 24.98″, a change of +2.2%. 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 195/65R15?
- At an indicated 60 mph you are really doing about 61.3 mph, a +2.2% error. The speedometer reads low, so you are going faster than it shows.
- What is the difference in revolutions per mile between 195/55R16 and 195/65R15?
- 195/55R16 turns about 825 times per mile and 195/65R15 turns about 807, a difference of −18. Your speedometer and odometer both count rotations, so this number is what throws them off.